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NetLogo 4.1.2 User Manual - Center for Human Science

1. 5 each turtle makes a red splotch of patches in a 60 degree cone of radius 3 ahead of itself in lt breed gt neighbor in link neighbor in lt breed gt neighbor agent in link neighbor turtle Reports true if there is a directed link going from turtle to the caller crt 2 ask turtle 0 create link to turtle 1 show in link neighbor turtle 1 prints false show out link neighbor turtle 1 prints true ask turtle 1 show in link neighbor turtle 0 prints true show out link neighbor turtle 0 prints false in lt breed gt neighbors in link neighbors in lt breed gt neighbors in link neighbors Reports the agentset of all the turtles that have directed links coming from them to the caller crt 4 ask turtle 0 create links to other turtles ask turtle 1 ask in link neighbors set color blue turtle 0 turns blue in lt breed gt from in link from in lt breed gt from turtle in link from turtle Report the directed link from turtle to the caller If no link exists then it reports nobody crt 2 ask turtle 0 create link to turtle 1 ask turtle 1 show in link from turtle 0 shows link O 1 NetLogo Dictionary 361 NetLogo 4 1 2 User Manual ask turtle 0 show in link from turtle 1 shows nobody See also out link to link with _ includes _ includes filename Causes external NetLogo source files with the n1s suffix to be included in this model
2. Interface Information Procedures F i a Y view updates A E E abc Button w O Feminis Settings io continuous rey A Edit Delete Add normal speed Right below the row of tabs is a toolbar containing a row of controls The controls available vary from tab to tab Interface Tab The Interface tab is where you watch your model run It also has tools you can use to inspect and alter what s going on inside the model When you first open NetLogo the Interface tab is empty except for the View where the turtles and patches appear and the Command Center which allows you to issue NetLogo commands Working with Interface Elements The toolbar on the Interface tab contains buttons that let you edit delete and create items in the Interface tab and a menu that lets you select different interface items such as buttons and sliders 2 E abc Button w l Edit te Add gt ax Button SEE slider 18 Switch E Chooser Input 5 Monitor Plot ES Output nx Note The buttons in the toolbar are described below Adding To add an interface element select the element from the the drop down menu Note that the Add button becomes pressed Then click on the white area below the toolbar If the menu is already showing the right type you can just press the Add button instead of using the menu again Selecting To select an interface element drag a rectangle around it with your mouse A gray b
3. At present the source code for most of NetLogo is not publicly available We are working on eventually releasing the source under an open source license BehaviorSpace however is free and open source software under the GNU LGPL license Also all of the extensions currently bundled with NetLogo are free and open source You will find the source code for BehaviorSpace and the bundled extensions included in the NetLogo distribution NetLogo is not a closed platform We provide APIs for controlling NetLogo from external code and extending the language with new commands and reporters See Controlling and Extensions in the User Manual We encourage users to write NetLogo extensions and share them with the NetLogo user community Do you offer any workshops or other training opportunities for NetLogo We offer workshops from time to time If a workshop has been scheduled we will announce it on the netlogo users group 302 FAQ Frequently Asked Questions NetLogo 4 1 2 User Manual Are there any NetLogo textbooks See the Textbooks section of our Resources page We at the CCL have hoped to write several NetLogo textbooks for quite some time These could be aimed at different audiences such as middle school high school undergraduate course in modeling or complexity practical guide for interested adults Unfortunately we have not yet been able to find the time to make these happen If anyone from the user community would like to
4. NetLogo Dictionary 431 NetLogo 4 1 2 User Manual 432 NetLogo Dictionary
5. 3 L ow Em im IE Mie gt ES a ABRAM ae 9 gt a a gt I amp S amp OS IRA o a 4 O ES E T P Ma J m y Ex M y OE A ne E AM sr S gt RAE An O gt 4 F de 156 Shapes Editor Guide NetLogo 4 1 2 User Manual By default there is only one Link shape in a model that is default This shape is simply a single straight line with a simple arrowhead if the link happens to be directed Creating and editing turtle shapes Pressing the New button will make a new shape Or you may select an existing shape and press Edit Tools In the upper left corner of the editing window is a group of drawing tools The arrow is the selection tool which selects an already drawn element To draw a new element use one of the other seven tools e The line tool draws line segments e The circle square and polygon tools come in two versions solid and outline When using the polygon tool click the mouse to add a new segment to the polygon When you re done adding segments double click After you draw a new element it is selected so you can move delete or reshape it if you want e To move it drag it with the mouse e To delete it press the Delete button e To reshape it drag the small handles that appear on the element only when it is selected e To change its color click on the new color Shapes Editor Guide 157 NetLogo 4 1 2
6. HubNet Control Center Name everreau Clients Activity Disease Server address 129 105 244 165 Port number 9173 Settings Mirror 2D view on clients 5 Mirror plots on clients experimental Kick Local Reset 0 A v Broadcast Message The HubNet Control Center lets you interact with the HubNet server It displays the name activity address and port number of your server The Mirror 2D View on clients checkbox controls whether the HubNet participants can see the view on their clients assuming there is a view in the client setup The Mirror plots on clients checkbox controls whether participants will receive plot information HubNet Guide 185 NetLogo 4 1 2 User Manual The client list on the right displays the names of clients that are currently connected to you activity To remove a participant from the activity select their name in the list and press the Kick button To launch your own HubNet client press the Local button this is particularly useful when you are debugging an activity The Reset button kicks out all currently logged in clients and reloads the client interface The lower part of the Control Center displays messages when a participant joins or leaves the activity To broadcast a message to all the participants click on the field at the bottom type your message and press Broadcast Message Client Applets Client applets use the same client interface as the clients run
7. e Direction Indicator the direction indicator the little arrow on directed links is just like the turtle vector shapes you can edit it using the same editor by pressing the Edit button e Curviness this is the amount of bend in a link expressed in patches this is particularly useful if you have directed links going in both directions so you can discern both links e Number of lines You can have 1 2 or 3 lines in each link shape you control this by selecting line patterns in the left line middle line and right line selection boxes e Dash pattern of lines There are several dashed line patterns available in the selection boxes so not all lines need be solid Here are a few link shapes with various properties Shapes Editor Guide 159 NetLogo 4 1 2 User Manual Using shapes in a model In the model s code or in the command center you can use any of the shapes that are in the model though only turtles can have turtle shapes and only links can have link shapes For example suppose you want to create 50 turtles with the shape rabbit Provided there is some turtle shape called rabbitin this model give this command to the observer in the command center observer gt crt 50 And then give these commands to the turtles to spread them out then change their shape turtles gt fd random 15 turtles gt set shape rabbit Voila Rabbits Note the use of double quotes around the shape name Shape names are strings Simila
8. exp exp number Reports the value of e raised to the number power Note This is the same as e number export view export interface export output export plot export all plots export world export view filename export interface filename export output filename export plot plotname filename export all plots filename export world filename export view writes the current contents of the current view to an external file given by the string filename The file is saved in PNG Portable Network Graphics format so it is recommended to supply a filename ending in png export interface is similar but for the whole interface tab export output writes the contents of the model s output area to an external file given by the string filename If the model does not have a separate output area the output portion of the Command Center is used export plot writes the x and y values of all points plotted by all the plot pens in the plot given by the string plotname to an external file given by the string filename If a pen is in bar mode mode 0 and the y value of the point plotted is greater than 0 the upper left corner point of the bar will be exported If the y value is less than 0 then the lower left corner point of the bar will be exported export all plots writes every plot in the current model to an external file given by the string filename Each plot is identical in format to the output of export plot export world writes the
9. nested NetLogo list simple list The simple list must have a length equal to the number of columns in the matrix i e the matrix row length 246 Matrix Extension NetLogo 4 1 2 User Manual matrix set column matrix set column matrix col j simple list Changes the given matrix matrix by replacing the column at col with the contents of the simple not nested NetLogo list simple list The simple list must have a length equal to the number of rows in the matrix i e the matrix column length matrix swap rows matrix swap rows matrix row1 row2 Changes the given matrix matrix by swapping the rows at row7 and row2 with each other matrix swap columns matrix swap columns matrix col1 col2 Changes the given matrix matrix by swapping the columns at co 1 and co 2 with each other matrix set and report matrix set and report matrix row i col j new value Reports a new matrix which is a copy of the given matrix except that the value at row i col j has been changed to new value A NetLogo statement such as let mat matrix set and report mat 2 3 10 will result in mat pointing to this new matrix a copy of the old version of mat with the element at row 2 column 3 being set to 10 The old version of mat will be lost matrix dimensions matrix dimensions matrix Reports a 2 element list num rows num cols containing the number of rows and number of columns in the given matrix matrix submatrix matrix submatrix matrix r1 c1 r2 c2
10. random random number If number is positive reports a random integer greater than or equal to O but strictly less than number If number is negative reports a random integer less than or equal to 0 but strictly greater than number If number is zero the result is always O as well Note In versions of NetLogo prior to version 2 0 this primitive reported a floating point number if given a non integer input This is no longer the case If you want a floating point answer you must now use random float instead show random 3 NetLogo Dictionary 395 NetLogo 4 1 2 User Manual Pe prints 0 Ly or 2 show random 3 A prIntse 0 p 0 2 show random 3 5 Pp Prints 0 DZ NOS See also random float random float random float number If number is positive reports a random floating point number greater than or equal to O but strictly less than number If number is negative reports a random floating point number less than or equal to 0 but strictly greater than number If number is zero the result is always 0 show random float 3 7 prints a number at least 0 but less than 3 for example 2 589444906014774 show random float 2 5 5 prints a number at least O but less than 2 5 for example 1 0897423196760796 random exponential random gamma random normal random poisson random exponential mean random gamma alpha lambda random normal mean standard deviation random poisson mean Reports an accordingly dist
11. NetLogo 4 1 2 User Manual NetLogo 4 1 2 User Manual Table of Contents AI nn A 1 ESTOS ui A A A DA AAA sd 1 Copyright and License InfOrmationy ccconcniociacadas nacido ina ia ica dio costa nnmnnn nnan n nnmnnn nnmnnn nnmnnn 3 How to felerence A ted ee Sos SA Ei lak 3 ACknOWlCGOMeNtS iia eta 3 NetLogo license ironia it ai aaa aia dea aaa 3 BBNAVIOFS DACOIICGNSS ecards idade A A ia a dida 3 EXTENSION ICONOS di co T 3 Third party CENSOS iia A e 4 Scala tr tt titi q Is Ends re 4 Mersenne TwisterFast treta anno nn nann narran nn rra ana nan EAEEREN REER nnen nnna 4 BOT Cae e o ana dl Ea 5 MRJ Adapter ia Ad ith caer alae 5 A Lie DU ADE A A Ai aaa 5 UOT AW 2c 2 oes eee ias Ret dada di ed dE O al dia oe ote NS SD ad paid Aa Rea ag a pa nan 5 MovIGENCOdEL ais tds titres paia a 6 Jpeglmages TOM VI aii A e da da o 6 JOG 2 iach tee cruise A A aqu cues 7 MENE A A NO a 8 ASMA A cin 8 Lat Sais 9 alelo EAE A E E nd Stee tute e SO 9 JTS Topology SUIS asma tec denis Ra uia e sairia TATA dices da a e Sa cote 10 ICAC lA OU pa 10 JAVA Advanced Imaging API Version 1 1 3 erraram 11 Apache Commons Codel micro iO 11 Apache Jakarta EP ii oli 11 Apache Commons LONA eie a ai A 12 What s New iii ana ad 13 Version 4 1 2 December 2010Ol occcoooncnnccccccnnncccnconcnnonconnnnoncncnnnononnnnnononrnnnnnonrnnnnnencnnennononeonos 13 Version 4 1 1 August 2010 oooooonooonconcconcconononnnnnnnnnnonononononononnnnnnnnnnnnnnnnnnnn
12. e a VectorFeature in which case the object s spatial representation is defined by the point line or polygon the feature contains e A turtle in which case the spatial representation is a point e A link whose spatial representation is a line segment connecting the two points represented by the turtles the link is connecting e A patch whose spatial representation is a rectangular polygon e An agentset whose spatial representation is the union of the representations of all of the agents it contains e A list containing of any of the items listed here including another list The spatial representation of such a list is the union of the spatial representations of its contents gis contains gis contains x y Reports true if every point of ys spatial representation is also a part of x s spatial representation Note that this means that polygons do contain their boundaries The objects x and y may be any one of e a VectorDataset in which case the object s spatial representation is the union of all the points lines or polygons the dataset contains e a VectorFeature in which case the object s spatial representation is defined by the point line or polygon the feature contains e A turtle in which case the spatial representation is a point e A link whose spatial representation is a line segment connecting the two points represented by the turtles the link is connecting e A patch whose spatial representation is a rectangular
13. n of n of size agentset n of size list From an agentset reports an agentset of size size randomly chosen from the input set with no repeats From a list reports a list of size size randomly chosen from the input set with no repeats The items in the result appear in the same order that they appeared in the input list If you want them in random order use shuffle on the result It is an error for size to be greater than the size of the input ask n of 50 patches set pcolor green 7 50 randomly chosen patches turn green See also one of n values n values size reporter Reports a list of length size containing values computed by repeatedly running reporter In reporter use to refer to the number of the item currently being computed starting from zero show n values 5 1 gt 1 1 1 1 1 show n values 5 gt 0 1 2 3 4 show n values 3 turtle gt turtle 0 turtle 1 turtle 2 show n values 5 gt 0 1 4 9 16 See also reduce filter NetLogo Dictionary 381 NetLogo 4 1 2 User Manual neighbors neighbors4 neighbors neighbors4 dx Pg Reports an agentset containing the 8 surrounding patches neighbors or 4 surrounding patches neighbors4 show sum count turtles here of neighbors 7 prints the total number of turtles on the eight patches around this turtle or patch show count turtles on neighbors 7 a Shorter way to say the same thing ask neighbor
14. o 112 Random Numbers iio ria 114 AUX ONO ira TIO A ve E E E E cds 115 Local randomness Sareat E i e A esd dec ta Es aah E ada Le reais 115 A ON 115 Link SAPOS ai os 116 TIC GOUN ICT A AA A AA er li 116 MA A De ace Dinda a Natal Nee DD a datada De aa ihe O Ea ad 116 ErachionalCKS ss go sr A CA Rad aa te 117 View Updates iii adenda 117 Continu s Upata 117 Tick based Updales c aacute re e ee Eaa ada dd daa 118 ENCOSMA AMIA nda ca RN a E e a 118 PlOUMING si siso rastrear seiras ice 119 O pg DOE RS sitet hind SG haeacea nei 122 OPUS 123 FIGO a E EE td EE E a O RAS DR Be Re IA EN 124 MOVIES iai NR 125 Peret Oui rindo copiada a Museen IA AA pa da ed 126 DEA WIN rosario e EEE ERES ATO RI ETTA PIO GT AS aa das ag Si aa Et 126 MO POIOG Vi A andes doca no AN ACE RN E a ER een adem Tea E AS 128 LINKS e al OS SS 132 FATSILGLOTO p 610 df a PRESS RR to PO RNA RE DRE A CAS EEE ARDE CRER 135 SUSE us AS Da Mates Mee O ci Sean E aca rec Dora a ao O te Do alo uu ee a ba de doi a od 136 MUS SOURCE MES era asso pes ini aaa Ad IA a OM ras ia Ada Sia 137 EVITA auge ira ris lie Ed A A 137 COlOrS cistos E E Aue Onda Da Dedos Si doada decade Seta DOS Ea BUD ad bt 137 A a da DR a ia pao a faites shapes q 4 E Soares A ESSA RS anaes 138 KEV WOMS cc 250 iraner adiado cad renan nin do ETE dead Read neaheccweneced qcceceasasteaedbas dabceddeceatuaeeuteseabents 138 Identifiers asas tees io eee wad SAD Sa as 138 COPS cassa tan a A AS O Rieeseeatc 1
15. 0 493 0 014 Incl T ms 26 066 6 413 0 177 Excl T ms 19 476 6 413 0 177 Excl calls 1 498 0 493 0 014 Incl T ms 26 066 Excl T ms 19 476 Excl calls 1 498 277 NetLogo 4 1 2 User Manual 278 Profiler Extension GIS Extension This extension provides the ability to load vector GIS data points lines and polygons and raster GIS data grids into NetLogo The extension supports vector data in the form of ESRI shapefiles The shapefile shp format is the most common format for storing and exchanging vector GIS data The extension supports raster data in the form of ESRI ascii Grid files The ascii grid file asc or grd is not as common as the shapefile but is supported as an interchange format by most GIS platforms We would love to hear your suggestions on how to improve the GIS extension or just about what you re using it for Please send all correspondence to Eric Russell and the NetLogo team at ccl gis northwestern edu How to use See the included code example GIS General Examples for general examples of how to use the extension or the code example GIS Gradient Example for a more advanced example of raster dataset analysis In general you first define a transformation between GIS data space and NetLogo space then load datasets and perform various operations on them The easiest way to define a transformation between GIS space and NetLogo space is to take the union of the env
16. 48 Tutorial 2 Commands NetLogo 4 1 2 User Manual e In the Command Center select observer from the popup menu or use the tab key e Type ask turtle 0 set color blue and press return What happens Just as there are Turtle Monitors there are also Patch Monitors Patch monitors work very similarly to Turtle Monitors Can you make a patch monitor and use it to change the color of a single patch If you try to have the observer ask patch 0 set pcolor blue you ll get an error message Command Center Clear ERROR Expected a number here rather than a list or block patches gt ask patch 0 set pcolor blue 7 v To ask an individual turtle to do something we use its who number But patches don t have who numbers therefore we need to refer to them some other way Remember patches are arranged on a coordinate system Two numbers are needed to plot a point on a graph an x axis value and a y axis value Patch locations are designated in the same way as plotting a point e Open a patch monitor for any patch Tutorial 2 Commands 49 NetLogo 4 1 2 User Manual The monitor shows that for the patch in the picture its pxcor variable is 19 and its pycor variable is 0 If we go back to the analogy of the coordinate plane and wanted to plot this point the point would be found in the lower left quadrant of the coordinate plane where x 19 and y 0 To tell this particular patch to cha
17. 500 and the turtle will move Note that we are using one kind of temperature sensor for which resistance decreases with temperature and so the sensor readings will go down as we heat the sensor up This is a very common and inexpensive off the shelf sensor A more elaborate use of this sensor apparatus would be to control output devices such as motors The user could for example turn a motor on when the value from the temperature sensor reaches 500 using the following code to turn motor on with heat if gogo sensor 1 lt 500 gogo talk to output ports a gogo output port on 268 NetLogoLab and the GoGo Board Extension NetLogo 4 1 2 User Manual end Another possible use of the sensing primitives is to plot and log data Logging could be useful for more elaborate data analysis and comparison and can be achieved with NetLogo s list commands For example if the user wants to log sensor values from sensor 1 every 0 5 seconds the code could look like this to log data from sensor set data vector lput gogo sensor 1 data vector wait 0 5 end Finally plotting data is straightforward The following code for example would create a graph for the value of sensor 1 plot gogo sensor 1 For more information on the GoGo Board s extensions functionalities and primitives please refer to these two sample models GoGoMonitor nlogo and GoGoMonitorSimple nlogo Primitives gogo burst value gogo close gogo open gogo open
18. For example a button that says go on it usually contains the code go which means run the go procedure Procedures are defined in the Procedures tab see below But you can also edit a button and enter a display name for the button which is a text that appears on the button instead of the code You might use this feature if you think the actual code would be confusing to your users When you put code in a button you must also specify which agents you want to run that code You can choose to have the observer run the code or all turtles or all patches or all links If you want the code to be run by only some turtles or some patches you could make an observer button and then have the observer use the ask command to ask only some of the turtles or patches to do something When you edit a button you have the option to assign an action key This makes that key on the keyboard behave just like a button press If the button is a forever button it will stay down until the key is pressed again or the button is clicked Action keys are particularly useful for games or any model where rapid triggering of buttons is needed Buttons take turns More than one button can be pressed at a time If this happens the buttons take turns which means that only one button runs at a time Each button runs its code all the way through once while 106 Programming Guide NetLogo 4 1 2 User Manual the other buttons wait then the next button ge
19. How to reference To reference NetLogo in academic publications please use Wilensky U 1999 NetLogo http ccl northwestern edu netlogo Center for Connected Learning and Computer Based Modeling Northwestern University Evanston IL Acknowledgments The CCL gratefully acknowledges over a decade of support for our NetLogo work Much of that support came from the National Science Foundation grant numbers REC 9814682 and REC 0126227 with further support from REC 0003285 REC 0115699 DRL 0196044 CCF ITR 0326542 DRL REC ROLE 0440113 SBE 0624318 EEC 0648316 IIS 0713619 DRL RED 9552950 and DRL REC 9632612 Additional support came from the Spencer Foundation Texas Instruments and the Brady Fund NetLogo license Copyright 1999 2010 by Uri Wilensky All rights reserved The NetLogo software models and documentation are distributed free of charge for use by the public to explore and construct models Permission to copy or modify the NetLogo software models and documentation for educational and research purposes only and without fee is hereby granted provided that this copyright notice and the original author s name appears on all copies and supporting documentation For any other uses of this software in original or modified form including but not limited to distribution in whole or in part specific prior permission must be obtained from Uri Wilensky The software models and documentation shall not be used rewritten or adapte
20. Included files may contain breed variable and procedure definitions __ includes can only be used once per file in radius agentset in radius number Reports an agentset that includes only those agents from the original agentset whose distance from the caller is less than or equal to number This can include the agent itself The distance to or a from a patch is measured from the center of the patch ask turtles ask patches in radius 3 set pcolor red 7 each turtle makes a red splotch around itself inspect inspect agent Opens an agent monitor for the given agent turtle or patch inspect patch 2 4 an agent monitor opens for that patch inspect one of sheep 77 an agent monitor opens for a random turtle from 7 the sheep breed int int number Reports the integer part of number any fractional part is discarded show int 4 7 gt 4 show int 3 5 gt 3 362 NetLogo Dictionary NetLogo 4 1 2 User Manual is agent is agentset is boolean is lt breed gt is directed link is link is link set is list is number is patch is patch set is string is turtle is turtle set is undirected link is agent value is agentset value is boolean value is lt breed gt value is directed link value is link value is link set value is list value is number value is patch value is patch set value is string value is turtle value is turtle set value is directe
21. LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING MODIFYING OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE PROFIT OR DATA OR FOR DIRECT INDIRECT SPECIAL CONSEQUENTIAL INCIDENTAL OR PUNITIVE DAMAGES HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY ARISING OUT OF THE USE OF OR INABILITY TO USE SOFTWARE EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES This software is not designed or intended for use in on line control of aircraft air traffic aircraft navigation or aircraft communications or in the design construction operation or maintenance of any nuclear facility Licensee represents and warrants that it will not use or redistribute the Software for such purposes JOGL For 3D graphics rendering NetLogo uses JOGL a Java API for OpenGL For more information about JOGL see http jogl dev java net The library is distributed under the BSD license Copyright c 2003 2006 Sun Microsystems Inc All Rights Reserved Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met Redistribution of source code must retain the above copyright notice this list of conditions and the following disclaimer Redistribution in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the docume
22. Notice how the turtles cover the lines and the lines cover the patch colors The pen size used here was 2 The stamp command lets a turtle leave an image of itself behind in the drawing and stamp erase lets it remove the pixels below it in the drawing To erase the whole drawing use the observer commmand clear drawing You can also use clear al1 which clears everything else too Importing an image The observer command import drawing command allows you to import an image file from disk into the drawing import drawing is useful only for providing a backdrop for people to look at If you want turtles and patches to react to the image you should use import pcolors Or import pcolors rgb instead Comparison to other Logos Drawing works somewhat differently in NetLogo than some other Logos Notable differences include e New turtles pens are up not down e Instead of using a fence command to confine the turtle inside boundaries in NetLogo you edit the world and turn wrapping off Programming Guide 127 NetLogo 4 1 2 User Manual e There is no screen color bgcolor or setbg You can make a solid background by coloring the patches e g ask patches set pcolor blue Drawing features not supported by NetLogo e There is no window command This is used in some other Logos to let the turtle roam over an infinite plane e There is no flood or fill command to fill an enclosed area with color Topology The topology
23. Reports an empty patch agentset not not boolean Reports true if boolean is false otherwise reports false if not any turtles crt 10 no turtles no turtles Reports an empty turtles agentset 384 NetLogo Dictionary NetLogo 4 1 2 User Manual O of reporter of agent reporter of agentset For an agent reports the value of the reporter for that agent turtle or patch show pxcor of patch 3 5 7 prints 3 show pxcor of one of patches 7 prints the value of a random patch s pxcor variable show who who of turtle 5 gt 25 show count turtles in radius 3 of patch 0 0 7 prints the number of turtles located within a 7 three patch radius of the origin For an agentset reports a list that contains the value of the reporter for each agent in the agentset in random order crt 4 show sort who of turtles gt 0 1 2 3 show sort who who of turtles gt 0 1 4 9 one of one of agentset one of list From an agentset reports a random agent If the agentset is empty reports nobody From a list reports a random list item It is an error for the list to be empty ask one of patches set pcolor green 7 a random patch turns green ask patches with any turtles here show one of turtles here for each patch containing turtles prints one of those turtles 7 suppose mylist is 1 2 3 4 5 6 show one of mylist 7 prints a value randomly chosen from the li
24. Sliders and SWItCh8S coccccccconnonononnnnncccnnnnnononnnncnnnnnnnnnnnnnnnnnnnrnnnnnnnnnnss 33 Gathering Information Plots and MONITOES cccocnnoconcconnnoncnnnonanononononccnnnnnnnnononcnnnnnnnnnnnnnnnos 35 nd 6 E ETE RO 35 MONOS soii ti a IS eee 36 Controlling AASV OW stas a e 36 The Models Libra Y oooocinicnnninicncocccccccccccnc cnn nr 40 Sample Modalidad 40 Perspective DEMOS cicatrices 40 Curricular ModelS sa sesta tot de tita Sra RE ei ii tie dea 40 Gods EXAMPISS ssa anta MORO da A ESA A OS 40 HubNetGomputer ACV asia A ii 40 Whats Next A sl 40 NetLogo 4 1 2 User Manual Table of Contents Tutorial H2 COMMAndS cucidocoosasionicn arca paaa p aa ara erpa a Tea SA aa Aaaa aa Aaa T a a Aaa a aae asena anis EEEE 41 Sample Model Traffic Basi cal 41 The Gommand Ce nter AAE E E A AE E EERTE ET ETAS TEETE T 41 A A EEr E NON 44 Agent Monitors and Agent COMMANde4S oooocccccnccccnnnnooonnncnnccnnnnannnonnnnnnnnnnnnnnnnrnncnnnnnnnannnnnnnss 46 AY ATAU FS Ex eD AANA E RA E A SU EE EAE 50 Tutorial 3 ProC Guresissiiissicsicices cicctsinies cicdaddocd 2hads chuacavades caicdandaaddldel divetaanteoswandisabedcaaddcawadedwocsties 51 Agents and proGedures ii IEA 51 Making the setup DUO aiii AA A AAA 51 Makina Theo DUO arias rc a parecido A A e 54 Experimenting with COMMAndS occcccccnnccnnccinnnnnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennnnenieninin 55 Patches and VU ds caia do 56 Turtle Variables iii
25. The agent a turtle or the observer sets its x coordinate to x its y coordinate to y and its z coordinate to z When the observer uses setxyz it remains facing the same point so the heading pitch and roll may also change 224 Introducing NetLogo 3D NetLogo 4 1 2 User Manual For turtles equivalentto set xcor x set ycor y set zcor z exceptit happens in one time step instead of three setxyz 0 0 0 77 agent moves to the middle of the center patch See also face T tilt down tilt up tilt down number tilt up number The nose of the turtle rotates by number degrees relative to its current orientation Depending on the orientation of the turtle more than one of the relative angles heading pitch and roll may change when a turtle turns towards pitch towards pitch nowrap towards pitch agent towards pitch nowrap agent Reports the pitch from this agent to the given agent If the wrapped distance around the edges of the screen is shorter than the on screen distance towards pitch will report the pitch of the wrapped path towards pitch nowrap never uses the wrapped path Note In order to get one turtle to face another you need to use both towards pitch and towards Note asking for the pitch from an agent to itself or an agent on the same location will cause a runtime error See also towards towards pitch xyz towards pitch xyz nowrap towards pitch xyz x yz towards pitch xyz no wrap x y z Reports
26. Turtle Shapes Editor The input file may contain any number of shapes with any number of rectangular or triangular surfaces The format of the input file should be as follows number of shapes in file name of first shape type of surface quads or tris surfacel surface2 stop type of surface surfaceA stop end shape Each surface is defined by a unit normal vector and the vertices listed in clockwise order tris should have three vertices and quads should have four 210 Introducing NetLogo 3D NetLogo 4 1 2 User Manual normal xn yn zn xl yl z1 x2 y2 Z2 x3 y3 z3 x4 y4 z4 A file declaring just a two dimensional patch sized square in the xy plane centered at the origin would look like this 1 square quads normal 0 0 1 O TS 0150 0 15 0 15 0 04 15 50 15 50 0615 0 15 50 normal 0 0 1 Ors 15 0 5150 0 15 0 15 0 0 15 081540 04 15 Quis 0 stop end shape Tutorial Step 1 Depth One of the first things you will notice when you open NetLogo 3D is that the world is a cube instead of a square You can open up the Model Settings by clicking on the Settings button at the top of the 3D View You ll notice in addition to max pxcor min pxcor max pycor and min pycor there is also max pzcor and min pzcor Introducing NetLogo 3D 211 NetLogo 4 1 2 User Manual 000 Model Settings World Location of origin Center HJ minimum x coordinate for patches max pxcor 16 ma
27. Turtles are compared by who number Patches are compared top to bottom left to right so patch O 10 is less than patch O 9 and patch 9 O is less than patch 10 O Links are ordered by end points and in case of a tie by breed So link O 9 is before link 1 10 as the end1 is smaller and link 0 8 is less than link O 9 If there are multiple breeds of links unbreeded links will come before breeded links of the same end points and breeded links will be sorted in the order they are declared in the Procedures tab Agentsets can be tested for equality or inequality Two agentsets are equal if they are the same type turtle or patch and contain the same agents If you are not sure how NetLogo will interpret your code you should add parentheses show 5 6 6 3 gt 32 show 5 6 6 3 gt 20 NetLogo Dictionary 323 NetLogo 4 1 2 User Manual asin asin number Reports the arc sine inverse sine of the given number The input must be in the range 1 to 1 The result is in degrees and lies in the range 90 to 90 ask ask agentset commands ask agent commands The specified agent or agentset runs the given commands ask turtles fd 1 all turtles move forward one step ask patches set pcolor red all patches turn red ask turtle 4 rt 90 7 only the turtle with id 4 turns right Note only the observer can ask all turtles or all patches This prevents you from inadvertently having all turtles ask all turtles or
28. above the origin looking straight down See also follow ride watch reset ticks reset ticks pe Resets the tick counter to zero See also tick ticks tick advance NetLogo Dictionary 401 NetLogo 4 1 2 User Manual reset timer reset timer Resets the timer to zero seconds See also timer Note that the timer is different from the tick counter The timer measures elapsed real time in seconds the tick counter measures elapsed model time in ticks resize world resize world min pxcor max pxcor min pycor max pycor gt Changes the size of the patch grid As a side effect all turtles and links die See also set patch size reverse reverse list reverse string Reports a reversed copy of the given list or string show mylist 5 mylist is 2 7 4 Bob set mylist reverse mylist 5 mylist now is Bob 4 7 2 show reverse live gt evil rgb rgb red green blue Reports a RGB list when three numbers describing an RGB color The numbers are range checked to be between 0 and 255 See also hsb ride ride turtle Set the perspective to turtle 402 NetLogo Dictionary NetLogo 4 1 2 User Manual Every time turtle moves the observer also moves Thus in the 2D View the turtle will stay at the center of the view In the 3D view it is as if looking through the eyes of the turtle If the turtle dies the perspective resets to the default See also reset perspective watch follow subjec
29. bottom right cell is gis width of dataset 1 gis height of dataset 1 gis set raster value gis set raster value RasterDataset x y value Sets the value of the given raster dataset at the given cell to a new value Cell coordinates are numbered from left to right and from top to bottom beginning with zero So the upper left cell is 0 0 and the bottom right cell is gis width of dataset 1 gis height of dataset 1 gis minimum of gis minimum of RasterDataset Reports the highest value in the given raster dataset gis maximum of gis maximum of RasterDataset Reports the lowest value in the given raster dataset gis sampling method of gis sampling method of RasterDataset Reports the sampling method used to compute the value of the given raster dataset at a single point or over an area smaller than a single raster cell Sampling is performed by the GIS extension primitives raster sample resample convolve and apply raster The sampling method will be one of GIS Extension 293 NetLogo 4 1 2 User Manual the following e NEAREST_NEIGHBOR the value of the cell nearest the sampling location is used e BILINEAR the value of the four nearest cells are sampled by linear weighting according to their proximity to the sampling site e BICUBIC the value of the sixteen nearest cells are sampled and their values are combined by weight according to a piecewise cubic polynomial recommended by Rifman see
30. e A global variable declared using globals e The global variable associated with a slider switch chooser or input box e A variable belonging to this agent e If this agent is a turtle a variable belonging to the patch under the turtle e A local variable created by the let command e An input to the current procedure set current directory set current directory string Sets the current directory that is used by the primitives file delete file exists and file open The current directory is not used if the above commands are given an absolute file path This is defaulted to the user s home directory for new models and is changed to the model s directory when a model is opened Note that in Windows file paths the backslash needs to be escaped within a string by using another backslash CN The change is temporary and is not saved with the model Note in applets this command has no effect since applets are only allowed to read files from the same directory on the server where the model is stored set current directory C NetLogo j Assume it is a Windows Machine file open my file txt Opens file C NetLogo my file txt set current plot set current plot plotname Sets the current plot to the plot with the given name a string Subsequent plotting commands will affect the current plot 406 NetLogo Dictionary NetLogo 4 1 2 User Manual set current plot pen set current plot pen penname The current p
31. e If you re install a specific NetLogo version on a machine where it is already installed the installer will get confused and print several error messages To re install while avoiding this issue first uninstall then re install This issue does not arise when installing a different version of NetLogo only when re installing the same exact version e On some laptops the Procedures and Info tabs may become garbled when you scroll them To avoid this bug reduce the size of the NetLogo window and or reduce the color depth of your monitor e g change from 32 bit to 16 or 8 bit color This is a bug in Java itself not in Known Issues 23 NetLogo 4 1 2 User Manual NetLogo per se For technical details on the bug see http developer java sun com developer bugParade bugs 4763448 html free registration required NetLogo users are encouraged to visit that site and vote for Sun to fix this bug Macintosh only bugs e When opening a model from the Finder by double clicking on it or dragging it onto the NetLogo icon if NetLogo is not already running then the model may or may not open the bug is intermittent If NetLogo is already running the model always opens Linux UNIX only bugs e We have discovered a problem on Linux where the exp reporter sometimes returns a slightly different answer differing only in the last decimal place for the same input According to an engineer at Sun this should only happen on Linux kernel versio
32. each node has a link with another node The relationship between spouses or siblings could be modeled as an undirected link There is a global agentset of all links just as with turtles and patches You can create undirected links using the create 1ink with and create links with commands and directed links using the create link to create links to create link from and create links from commands Once the first link has been created directed or undirected all unbreeded links must match links also support breeds much like turtles which will be discussed shortly it s impossible to have two unbreeded links where one is directed and the other is undirected A runtime error occurs if you try to do it If all unbreeded links die then you can create links of that breed that are different in flavor from the previous links In general primitives that work with directed links have in out to and from in their names Undirected ones either omit these or use with 132 Programming Guide NetLogo 4 1 2 User Manual Link breeds like turtle breeds allow you to define different types of links in your model Link breeds must either be directed or undirected unlike unbreeded links this is defined at compile time rather than run time You declare link breeds using the keywords undirected 1ink breed and directed 1ink breed Breeded links can be created using the commands create lt breed gt with and create lt breeds gt with for undirect
33. empty string gt false first string gt s item 2 string gt r last string gt g length string gt 6 member s string gt true member rin string gt true member ron string gt false position s string gt 0 position rin string gt 2 position ron string gt false remove r string gt sting 122 Programming Guide NetLogo 4 1 2 User Manual remove s strings gt tring replace item 3 string o gt strong reverse string gt gnirts A few primitives are specific to strings such as is string substring and word is string string gt true is string 37 gt false substring string 2 5 gt rin word tur tle gt turtle Strings can be compared using the lt gt lt and gt operators If you need to embed a special character in a string use the following escape sequences e n newline e t tab e double quote e backslash Output This section is about output to the screen Output to the screen can also be later saved to a file using the export output command If you need a more flexible method of writing data to external files see the next section File I O The basic commands for generating output to the screen in NetLogo are print show type and write These commands send their output to the Command Center For full details on these four commands see their entries in the NetLogo Dic
34. gogo ports gogo output port coast gogo output port off gogo output port reverse gogo output port thatlthis way gogo ping gogo sensor gogo set burst mode gogo set output port power gogo stop burst mode gogo talk to output ports gogo burst value gogo burst value sensor Reads the most recent value that was received by the gogo board from a sensor set to send burst data See also gogo set burst mode and gogo stop burst mode gogo close gogo close Close the connection to the GoGo Board See also gogo open and gogo open gogo open gogo open pori name Open a connection to the GoGo Board connected to serial port named port name See gogo ports for more information about port names NetLogoLab and the GoGo Board Extension 269 NetLogo 4 1 2 User Manual If the GoGo Board is not responding or you attempt to open a port without a GoGo Board connected to it an error will be generated Example gogo open COM1 See also gogo open and gogo close gogo open gogo open Reports true if there is a connection to a GoGo Board open Reports false otherwise gogo ports gogo ports Reports a list of serial port names that a GoGo Board may be connected to On certain computers you might get a list of two or three different serial ports In that case try to open each of them until the connection is successful gogo output port coast gogo output port coast Turns off the power of the active ports When attached to motors
35. show mouse 1 7 prints mouse 1 show frog 51 7 prints frog 51 show turtle 51 7 prints frog 51 See also globals patches own turtles own lt breeds gt own create lt breeds gt lt breeds gt at lt breeds gt here but first butfirst bf but last butlast bl but first list but first string but last list but last string When used on a list but first reports all of the list items of list except the first and but last reports all of the list items of list except the last On strings but first and but last report a shorter string omitting the first or last character of the original string 5 mylist is 2 4 6 5 8 12 set mylist but first mylist 7 mylist is now 4 6 5 8 12 set mylist but last mylist 5 mylist is now 4 6 5 8 show but first string 7 prints tring show but last string 7 prints strin 328 NetLogo Dictionary NetLogo 4 1 2 User Manual C can move can move distance Reports true if this turtle can move distance in the direction it is facing without violating the topology reports false otherwise It is equivalent to patch ahead distance nobody carefully carefully commands1 commands2 Runs commands1 If a runtime error occurs inside commands 1 NetLogo won t stop and alert the user that an error occurred lt will suppress the error and run commands2 instead The error message reporter can be used in commands2 to find out what error was suppressed i
36. val workspace HeadlessWorkspace newInstance workspace open models Sample Models Earth Science Fire nlogo workspace command set density 62 workspace command random seed 0 workspace command setup workspace command repeat 50 go println workspace report burned trees workspace dispose In order to compile and run this Net Logo jar must be in your classpath The lib directory containing additional required libraries must also be present When running in a context that does not support a graphical display the system property java awt headless must be true to force the VM to run in headless mode Since there is no GUI NetLogo primitives which send output to the command center or output area now go to standard output instead export world can still be used to save the model s state export view works for writing an image file with a snapshot of the otherwise invisible 2D view The report method is useful for getting results out of the model and into your extension code The files generated by export wor1d include the contents of all plots You can also export the contents of plots individually using export plot You can make multiple instances of HeadlessWorkspace and they will operate independently on separate threads without interfering with each other When running headless there are some restrictions e The movie primitives are not available trying to use them will cause an excep
37. you could say ask max one of turtles sum assets die e Make a histogram of the agentset using the histogram command in combination with of e Use of to make a list of values one for each agent in the agentset Then use one of NetLogo s list primitives to do something with the list See the Lists section below For example to find out how rich turtles are on the average you could say show mean sum assets of turtles e Use turtle set patch set and link set reporters to make new agentsets by gathering together agents from a variety of possible sources e Check whether two agentsets are equal using or e Use member to see whether a particular agent is a member of an agentset This only scratches the surface See the Models Library for many more examples and consult the NetLogo Dictionary for more information about all of the agentset primitives More examples of using agentsets are provided in the individual entries for these primitives in the NetLogo Dictionary In developing familiarity with programming in NetLogo it is important to begin to think of compound commands in terms of how each element passes information to the next one Programming Guide 103 NetLogo 4 1 2 User Manual Agentsets are an important part of this conceptual scheme and provide the NetLogo developer with a lot of power and flexibility as well as being more similar to natural language Code Example Ask Ordering Example Earlier we said th
38. 0 10 12 gt 1 0E 12 You can also use scientific notation yourself in NetLogo code how 3 0E6 gt 3000000 how 8 123456789E gt 8123456 789 how 8 123456789E gt 8 123456789E7 how 3 0E16 0E16 how 8 0E 3 gt 0 0080 how 8 0E 4 gt 8 0E 4 oO V Ww o bo o po i al wi a These examples show that numbers with fractional parts are displayed using scientific notation if the exponent is less than 3 or greater than 6 Numbers outside of NetLogo s integer range of 9007199254740992 to 9007199254740992 2253 are also always shown in scientific notation show 2 60 gt 1 15292150460684698E18 When entering a number the letter E may be either upper or lowercase When printing a number NetLogo always uses an uppercase E show 4 5e20 gt 4 5E20 Floating point accuracy Because numbers in NetLogo are subject to the limitations of how floating point numbers are Programming Guide 113 NetLogo 4 1 2 User Manual represented in binary you may get answers that are slightly inaccurate For example show 0 1 0 1 0 1 gt 0 30000000000000004 show cos 90 gt 6 123233995736766E 17 This is an inherent issue with floating point arithmetic it occurs in all programming languages that use floating point numbers If you are dealing with fixed precision quantities for example dollars and cents a common technique is to use only integers cents internally then divid
39. 0 foreach sort patches ask set plabel n set nn 1 7 patches are labeled with numbers in left to right 7 top to bottom order sort by sort by reporter list sort by reporter agentset If the input is a list reports a new list containing the same items as the input list in a sorted order defined by the boolean true or false reporter In reporter use 21 and 2 to refer to the two objects being compared reporter should be true if 21 comes strictly before 2 in the desired sort order and false otherwise If the input is an agentset or a list of agents reports a list never an agentset of agents The sort is stable that is the order of items considered equal by the reporter is not disturbed show sort by 1 lt 2 3 1 4 2 gt 1 2 3 4 show sort by 1 gt 2 3 1 4 2 gt 4 3 2 1 show sort by length 1 lt length 2 Grumpy Doc Happy gt Doc Happy Grumpy foreach sort by size of 1 lt size of 2 turtles ask do something 7 turtles run do something one at a time in 7 ascending order by size 412 NetLogo Dictionary NetLogo 4 1 2 User Manual sprout sprout lt breeds gt sprout number commands o number commands Creates number new turtles on the current patch The new turtles have random integer headings and the color is randomly selected from the 14 primary colors The turtles immediately run commands This is useful for giving
40. 4 1 2 User Manual accomplished yields more happiness than does each snack consumed although both are positively correlated with happiness Also we see that R 2 0 98 so the two factors together provide a good fit Credits The Matrix extension for NetLogo was originally written by Forrest Stonedahl with significant contributions from Charles Staelin in particular the forecast regression primitives The matrix extension provides a wrapper around Jama which is a free open source matrix library for Java The source code for the Matrix extension is included and you are more than welcome to modify improve upon the existing functionality and features If you do so we encourage you to contribute back to the NetLogo community by sending your patches to feedback ccl northwestern edu Matrix Extension 253 NetLogo 4 1 2 User Manual 254 Matrix Extension Sound Extension The Sound Extension for NetLogo provides primitives to add sound to NetLogo models lt supports two ways of making sound MIDI sounds and playback of pre recorded sound files Using the Sound Extension The sound extension comes preinstalled To use the extension in your model add a line to the top of your procedures tab extensions sound If your model already uses other extensions then it already has an extensions line in it so just add sound to the list For more information on using NetLogo extensions see the Extensions Guide For exampl
41. 7 turtles move forward 6 patches foreach true false true true ask turtles if fd 1 7 turtles move forward 3 patches map is similar to foreach but it is a reporter lt takes an input list and another reporter Note that unlike foreach the reporter comes first like this show map round 1 2 2 2 2 7 ip prints 1 2 3 map reports a list containing the results of applying the reporter to each item in the input list Again use 2 to refer to the current item in the list Here is another example of map show map lt 0 1 1 3 4 2 10 7 prints false true false false true true foreach and map won t necessarily be useful in every situation in which you want to operate on an entire list In some situations you may need to use some other technique such as a loop using repeat Or while or a recursive procedure The sort by primitive uses a similar syntax to map and foreach except that since the reporter needs to compare two objects the two special variables 21 and 22 are used in place of 2 Here is an example of sort by show sort by 1 lt 2 4 1 3 2 jp prints 12 3 4 Varying number of inputs Some commands and reporters involving lists and strings may take a varying number of inputs In these cases in order to pass them a number of inputs other than their default the primitive and its inputs must be surrounded by parentheses Here are some examples show list 1 2 gt 1 2 s
42. 78 79 79 9 cyan 85 Sl Se 88 89 89 9 sky 95 91 S Oo 98 99 99 9 blue 105 101 102 103 108 109 109 9 violet 115 111 IZ gem 119 119 9 magenta 125 121 122 123 E E 128 129 129 9 pink 135 131 ee 137 138 139 1399 To get a color that doesn t have its own name you just refer to it by a number instead or by adding or subtracting a number from a name For example when you type set color red this does the same thing as if you had typed set color 15 And you can get a lighter or darker version of the same color by using a number that is a little larger or a little smaller as follows e Choose patches from the popup menu in the Command Center or use the tab key e Type set pcolor red 2 The spacing around the is important Tutorial 2 Commands 45 NetLogo 4 1 2 User Manual By subtracting from red you make it darker e Type set pcolor red 2 By adding to red you make it lighter You can use this technique on any of the colors listed in the chart Agent Monitors and Agent Commanders In the previous activity we used the set command to change the colors of all the cars But if you recall the original model contained one red car amongst a group of blue cars Let s look at how to change only one car s color e Press setup to get the red car to reappear e If you are on a Macintosh hold down the Control key and click on the red car On other operating systems click on the red car with the right m
43. A A A a de cb a ie 57 MONO Sicario ts a o o aides cules nicks aged de amp Dem da et RI a Deda de 59 Switches and labels aiii 61 More procedure Sian e aa Dl era e Geri ne as 63 PLOT Sor AAA DD DAS DO a and Tn Ela 64 TICKICOUNE E vege Sexe ves cados da pad 67 Some more detal 7 cur at as a a DO dt o A IS O O O O gaia de 68 WHATS NON A A is 69 Appendix Complete CO aii ni 70 Interface Guides tii accio id bodrio scacda 73 Men OR ll 73 Chart NetLogo MENUS ani A 73 TD O wees ca cue 75 NTS MACS ab esa ao A e A ao o O dd a dedo ado IM ue 76 Working with Interface Elements eee ananarerara aan anananaaas 76 Chart Interface Toolbar iuris Aid 77 AAA o o ui cana E Gas teats da NERE a dO A xt 78 Command GO da 82 Plot a dia 84 Sd Said A ae E E 85 Agent MONITO void A ASKE ste 85 INtOrMaton Ta A ee e o A A SO Rd ETT 87 Information Tab Markup a dd as Ed 88 MBA TAS TIT Lc ad S A A o 88 Rrocedires TA a e DE eo 2 da o 88 CIU MA a RED o Di et 91 Call e Og 91 Indent AutoMatiCallV iso a OCA E Weave asda sopa ans a nai ada 92 Programming QUIde E esparsas ias tocha latge ais SS as 93 O NN 93 PTOCOUTOS oi AA A ea eee ce ed eh 94 Vanables da a eee ea Medid 96 COM E EE A a o cate o gu o do 97 NetLogo 4 1 2 User Manual Table of Contents Programming Guide ASA A al 100 AOS AS iii A Ad 102 BECAS Mr tm A A A A OA AR 104 LINK BOS it aa 105 BUON SS it ti nated A a a 106 BA A RN ee as SE ad Ta 107 Malhas sintra e a a
44. Digital Image Warping George Wolberg 1990 pp 129 131 IEEE Computer Society Press e BICUBIC 2 the value is sampled using the same procedure and the same polynomial as with BICUBIC above but using a different coefficient This method may produce somewhat sharper results than BICUBIC but that result is data dependent UJ For more information on these sampling methods and on raster sampling in general see this wikipedia article gis set sampling method gis set sampling method RasterDataset sampling method Sets the sampling method used by the given raster dataset at a single point or over an area smaller than a single raster cell Sampling is performed by the GIS extension primitives raster sample resample convolve and apply raster The sampling method must be one of the following NEAREST_NEIGHBOR BILINEAR B ICUB EE BICUBIC_2 See sampling method of above for a more specific description of each sampling method gis raster sample gis raster sample RasterDataset sample location Reports the value of the given raster over the given location The location may be any of the following e A list of length 2 which is taken to represent a point in netlogo space xcor ycor of the sort reported by location of Vertex The raster dataset is sampled at the point of that location e A list of length 4 which is taken to represent
45. Dynamics Modeler window displays the NetLogo procedures generated from your diagram You can t edit the contents of the Procedures tab To modify your System Dynamics mode edit the diagram Let s take a closer look at how the generated code relates to the diagram e Stocks correspond to a global variable that is initialized to the value or expression you provided in the Initial value field Each Stock will be updated every step based on the Flows in and out e Flows correspond to a procedure that contains the expression you provided in the Expression field e Variables can either be global variables or procedures If the Expression you provided is a constant it will be a global variable and initialized to that value If you used a more complicated Expression to define the Variable it will create a procedure like a Flow The variables and procedures defined in this tab are accessible in the main NetLogo window just like the variables and procedures you define yourself in the main NetLogo Procedures tab You can call the procedures from the main Procedures tab from the Command Center or from buttons in the Interface tab You can refer to the global variables anywhere including in the main Procedures tab and in monitors There are three important procedures to notice system dynamics setup system dynamics go and system dynamics do plot system dynamics setup initializes the aggregate model It sets the value of at calls reset ticks a
46. ES DESEN E ge A 162 Managing experiment SCtUDS ooooocccocccoonoonooononononononnnnnnnononononononnnnnnonnnnnnnnnnnnnnnonnnnnnnnnnos 162 Creating an experiment SON is oscsssrccdacdecveseT ete ecetsaandianhecnadaniiie Set punir ad dai 3 ad 162 Special primitives for BehaviorSpace experiments isa 164 Running an EXPeriMeNt occccccccccnnnonnnonnnonnnonnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnninnnineniss 164 Advanced USADO sumiu eus sans anima o inci done soda 166 Running from the command hs ni ata 166 Setting up experiments in XML sses eseri ineei ieii aS 169 conto MITAD Ls san teat E EE E E A da 169 10 U1 01 gt 20010 EE re ip RP et rE ee 170 System Dynamics Guide si inicio eaa near ia ao tenes eee ees 171 What is the NetLogo System Dynamics Modeler c cccccccccccsssesceeeeeeeeessessssneeeeeeeeeeeee 171 Basic CONCISO 171 Sample Modals dia 172 HONA WORK S uses secas dourado tr ll dit ba UD 172 Diagram A A E E EEE 172 Procedures Dia AE AE AA EEA haves 175 The System Dynamics Modeler and NetLogQo ccccccconooococnccncconanannonccncnonnncnnnnnnnnnnnos 176 Tut rial Woll Sheep Prod ada 176 Step 1 Sheep ReproductiON oooooooccccccccconnnooncccnonnnccnnnnnnnnnnnnnncnnnnnnnnornrnnnnnnnnnannnonenennnnnns 176 Step 2 Neil dgo tear ais 179 S1900 3 WOlPESd Orta 180 mL ANARE E E A e E E A o tr 183 Understanding HubNet occccccnnccccccnnccnecenenenenenenenicnnncnnncnnnennnrrnnrrrn rena a rra 183 N
47. Found otherwise NetLogo thinks the following data is what it requested and tries to read it as such This happens even if all the files required to run the applet are present If you don t have control over the error messages on your web server you can use the following as a workaround e Create a directory named META INF in the same directory as the applet files e Create a subdirectory of META INF called services e Create a file called org apache commons 1ogging LogFactory in the services subdirectory e Add the following line to org apache commons logging LogFactory org apache commons logging impl LogFactoryImpl Note that all the directory and file names are case sensitive Running Can I run NetLogo from a CD a network drive or a USB drive Yes NetLogo runs fine from any file system including read only file systems Why is NetLogo so much slower when I unplug my Windows laptop Your computer is switching to power saving mode when unplugged It s normal for this to reduce speed a little but unfortunately there is a bug in Java that drastically slows down Swing applications including NetLogo One workaround is to change the power settings on your computer so it doesn t go into power saving mode when you unplug it If you do this your battery won t last as long Another workaround is to run NetLogo with an option recommended by Sun by editing the NetLogo 4 1 2 vmoptions file found in the NetLogo directory u
48. NetLogo 4 1 2 User Manual See also setxy xcor ycor pxcor pycor pzcor zoom zoom number pe Move the observer toward the point it is facing number steps The observer will never move beyond the point it is facing so if numberis greater than the the distance to that point it will only move as far as the point it is facing Introducing NetLogo 3D 227 NetLogo 4 1 2 User Manual 228 Introducing NetLogo 3D Extensions Guide NetLogo allows users to write new commands and reporters in Java and other languages and use them in their models This section of the User Manual introduces this facility The first part discusses how to use an extension in your model once you have written one or once someone has given you one The second part is intended for programmers interested in writing their own extensions using the NetLogo Extension API e Using Extensions e Writing Extensions The NetLogo Extension API Specification contains further details Using Extensions To use an extension in a model add the extensions keyword at the beginning of the Procedures tab before declaring any breeds or variables After extensions comes a list of extension names in square brackets For example extensions sound speech Using extensions tells NetLogo to find and open the specified extension and makes the custom commands and reporters found in the extension available to the current model You can use these commands and reporters just as if th
49. NetLogo itself Wilensky U 1999 NetLogo http ccl northwestern edu netlogo Center for Connected Learning and Computer Based Modeling Northwestern University Evanston IL HubNet Wilensky U amp Stroup W 1999 HubNet http ccl northwestern edu netlogo hubnet html Center for Connected Learning and Computer Based Modeling Northwestern University Evanston IL How do cite a model from the Models Library in a publication The correct citation is included in the CREDITS AND REFERENCES section of every model s Information tab Where and when was NetLogo created NetLogo was first created in 1999 by Uri Wilensky at the Center for Connected Learning and Computer Based Modeling then at Tufts University in the Boston area NetLogo grew out of StarLogoT which was authored by Wilensky in 1997 In 2000 the CCL moved to Northwestern University in the Chicago area NetLogo 1 0 came out in 2002 2 0 in 2003 3 0 in 2005 4 0 in 2007 and 4 1 in 2009 What programming language was NetLogo written in NetLogo is written mostly in Java Some parts such as BehaviorSpace and the compiler are written in Scala Scala code compiles to Java byte code and is fully interoperable with Java and other JVM languages FAQ Frequently Asked Questions 301 NetLogo 4 1 2 User Manual What s the difference between StarLogo MacStarLogo StarLogoT and NetLogo The original StarLogo was developed at the MIT Media Lab in 1989 1990 and ran
50. NetLogo world has width height and depth In addition to pxcor and pycor patches have pzcor Turtles have three Cartesian coordinates instead of two to describe position In addition to xcor and ycor turtles have zcor A turtle s orientation is defined by three turtle variables heading pitch and roll You can imagine the turtle as having two vectors to define its orientation in 3D space One vector comes straight out of the nose of the turtle this is the direction the turtle will travel when it moves forward The second vector is perpendicular to the forward vector and comes out of the right side of the turtle as if the turtle were to stick its right arm straight out from its body Heading is the angle between the forward vector of the turtle projected onto the xy plane and the vector O 1 0 Pitch is the angle Introducing NetLogo 3D 209 NetLogo 4 1 2 User Manual between the forward vector of the turtle and the xy plane and finally roll is the angle between the right vector of the turtle and the xy plane When turtle turns right or left in 3D space it rotates around the down vector that is the vector that is perpendicular to both the forward and right vectors Depending on the orientation of the turtle more than one of the internal turtle variables may change as the result of a turn The Observer and the 3D view The point of view that you see the world from is considered the location and orientation of the observer This is simila
51. Note for color shade is irrelevant e g green and green 2 are equivalent and the same spectrum of colors will be used ask turtles set color scale color red age 0 50 7 colors each turtle a shade of red proportional to its value for the age variable self self xx Ed Reports this turtle or patch self and myself are very different self is simple it means me myself means the turtle or patch who asked me to do what I m doing right now See also myself semicolon comments After a semicolon the rest of the line is ignored This is useful for adding comments to your code text that explains the code to human readers Extra semicolons can be added for visual effect NetLogo s Edit menu has items that let you comment or uncomment whole sections of code sentence se sentence value value2 sentence value Makes a list out of the values If any value is a list its items are included in the result directly rather than being included as a sublist Examples make this clearer show sentence 1 2 gt 1 2 show sentence 1 2 3 gt 1 2 3 show sentence 1 2 3 gt 1 2 3 show sentence 1 2 3 4 NetLogo Dictionary 405 NetLogo 4 1 2 User Manual gt 1 2 3 4 show sentence 1 21 3 4 gt 1 2 3 4 show sentence 1 2 3 4 5 3 3 7 gt 123 45 6 7 set set variable value Sets variable to the given value Variable can be any of the following
52. PAA PAN IE A ATEA T A A E ETE I E AA ease D SEG 402 A a aa a ae eee ee a ae aaa eRe 402 HOCUS E EEEE T E E E TE 402 Si do EE ERE ABE EEE E E A E E EE EEE EE E RREO EA RC TEE 402 AC Sel RO E E EIN TE E AE EEE 403 idto LAM i a eaea EASE E EEEE EET TES Swe vow eda E ES A E E DDR SP ve 403 A OAREN ERPI LESERE EEE ASA E EEEE ESEE EE A E ETEO qu PEETA ATE EE ETEINEN 403 PUN EEA TAE E AAE A AA TASE A O 404 UNS EEEE A E E E AEE EENI AE a OTET 404 EEEE IS RN O E EA IR AE E a OL 404 scalo COT aT A n A OA ld e a A AO cando 404 EE AEE E E E EEA ANTEA I E RAR 405 SOMICO Oia 405 SONTENCO li a A A A o Tudo Rad 405 SA a it e 406 SEt CUrreENt CIFECtONY ccoocoocccncccocccoccnoccnnccnnncnnrrnn rr 406 SOt CUIMTON EDO diiniita 406 S t current DIOL DEN iii AAA AA Aa 407 se detaul Shao rd 407 set histogram num bars nn 407 Sel ine ihickness aa cita hele calado loa Sica lo ls nais en E sa bon la Do thaslos idosas 408 SOPA SIZE AA AE DRA A da 408 set plot pen Collot sire n ag ina Aia RA RAR da RRA AAA A AR A Si 408 S t PlOt PEN INterVal eee cc cec cee c cece eee e eee e eee e rete eee rr rr 408 set plot pen Mode orar riadas 408 set plot x range set plot y range narrar 409 A ta as Aniian gestao ada eed dd cde deh ddd deta edd doar SADO aranha ade 409 snade ol dr eo ne O 409 Shape dit 409 Shapes ia A AAA satis Bu A es 410 e PU e REAR A RR O REI tube shee 410 Snowsturtle Str E ADO dE do A A ek E Oo da A A Di
53. PUTO Pla UR RR AR RE RR ones tes Sd N RAR RR MAR ARE E RN RR RR RR 211 St p LE Dos 211 FAQ Frequently Asked Questions usina lia 216 Can make patches or turtles translucent occccccnonocncocnncnccononanonnnnnncccnnnnnnnnoncnnnnnnnns 216 vii NetLogo 4 1 2 User Manual Table of Contents Introducing NetLogo 3D Commands and AGPOMOMS aida ida 217 Turtle related priMitiVES ccoccccncnncccnnccnnccnncnnncnnnenonennncnnnernnrnnnrrnn enn r ener 217 Built In Varlables ooccoooocccononiccncncnncncnnnnnonnnnnn cnc nonnnnnnono nan nn non nnnnnnno naar nn nn rn anna n anna rra narran 217 MUS e e e Sees 218 TN 218 al POINTS iS A 218 O E E E EEEE E E SEE N RN 218 distancexyz distancexyz nowrap eee eee rene 218 O MSN OITO AR MI PE OO E a faba 219 PACS TACON Zar A AAA ea St Sit 219 Mr A Ao sd e e NT AOS RATO aid A a 219 MES RAE SR E ope on PER RR 219 LNA chee atra tats td AN A IN a RR AA Eai ae a 220 MaX PzCOr MIN PzeOL s NEO 220 UN edocs AT adh A wate da da us O a St pate cao CRP ag ee ots it abe ibe aoe nto de Et A an 220 neighbors neignborsO ss sessions eE a dao datd a 220 DA DID DADO E ween baa A AA A CAR 221 orbit down orbit left orbit right orbit up e eerereiaaaeeenaaaaaaaaes 221 TR A aaa TARA ID UR 0 O A DA AD O A a A btt 221 Dai A adda dite a Dada boas ala duda settee 221 E ERA PNR REAR eat RARE Seatac sain is AR AS SR SRP RR ER 223 random PzCOl ss siri sons dd da 223 A O E
54. Procedures NetLogo 4 1 2 User Manual MAS ticks 0 009A Monitor Reporter kount patches with pcolor green count turtles green patches 50 1225 Display name green patches Decimal places 3 full precision is 17 Font Size 11 Cancel Cok Here we re using count again to see how many agents are in an agentset patches is the set of all the patches but we don t just want to know how many patches there are total we want to know how many of them are green That s what with does it makes a smaller agentset of just those agents for whom the condition in the brackets is true The condition is pcolor green so that gives us just the green patches Now we have two monitors that will report how many turtles and green patches we have to help us track what s going on in our model As the model runs the numbers in the monitors will automatically change e Use the setup and go buttons and watch the numbers in the monitors change Switches and labels The turtles aren t just turning the patches black they re also gaining and losing energy As the model runs try using a turtle monitor to watch one turtle s energy go up and down It would be nicer if we could see every turtle s energy all the time We will now do exactly that and add a switch so we can turn the extra visual information on and off e To create a switch click on the switch icon on the Toolbar in the Interface tab
55. Reports a list of lists of Vertex values For point datasets each vertex list will contain exactly one vertex the location of a point For line datasets each vertex list will contain at least two points and GIS Extension 285 NetLogo 4 1 2 User Manual will represent a polyline connecting each adjacent pair of vertices in the list For polygon datasets each vertex list will contain at least three points representing a polygon connecting each vertex and the first and last vertices in the list will be the same gis centroid of gis centroid of VectorFeature Reports a single Vertex representing the centroid center of gravity of the given feature For point datasets the centroid is defined as the average location of all points in the feature For line datasets the centroid is defined as the average of the locations of the midpoints of all line segments in the feature weighted by segment length For polygon datasets the centroid is defined as the weighted sum of the centroids of a decomposition of the area into possibly overlapping triangles See this FAQ for more details on the polygon centroid algorithm gis location of gis location of Vertex Reports a two element list containing the x and y values in that order of the given vertex translated into NetLogo world space using the current transformation or an empty list if the given vertex lies outside the NetLogo world gis property value gis property value VectorFeature prope
56. The Wolf Sheep Predation doesn t have any of these though Gathering Information Plots and Monitors A purpose to modeling is to gather data on a subject or topic that would be very difficult to do in a laboratory situation NetLogo has two main ways of displaying data to the user plots and monitors Plots The plot in Wolf Sheep Predation contains three lines sheep wolves and grass 4 The grass count is divided by four so it doesn t make the plot too tall The lines show what s happening in the model over time To see which line is which click on Pens in the upper right corner of the plot window to open the plot pens legend A key appears that indicates what each line is plotting In this case it s the population counts When a plot gets close to becoming filled up the horizontal axis increases in size and all of the data from before gets squeezed into a smaller space In this way more room is made for the plot to grow If you want to save the data from a plot to view or analyze it in another program you can use the Export Plot item on the File menu lt saves this information to your computer in a format that can by read back by spreadsheet and database programs such as Excel You can also export a plot by control clicking Mac or right clicking Windows it and choosing Export from the popup menu Tutorial 1 Models 35 NetLogo 4 1 2 User Manual Monitors Monitors are another method of displaying information in a
57. There are a few primitives that are helpful for working with colors We have already mentioned the wrap color primitive The scale color primitive is useful for converting numeric data into colors shade of will tell you if two colors are shades of the same basic hue For example shade of orange 27 is true because 27 is a lighter shade of orange Code Example Scale color Example demonstrates the scale color reporter RGB and RGBA Colors NetLogo also represents colors as RGB red green blue lists and RGBA red green blue alpha lists When using RGB colors the full range of colors is available to you RGBA colors allow all the colors that RGB allows and you can also vary the transparency of a color RGB and RGBA lists are made up of three or four integers respectively between 0 and 255 if a number is outside that range 255 is repeatedly subtracted until it is in the range You can set any color variables in NetLogo color for turtles and links and pcolor for patches to an RGB list and that agent will be rendered appropriately So you can set the color of patch O O to pure red using the following code set pcolor 255 0 0 Turtles links and labels can all contain RGBA lists as their color variables however patches cannot have RGBA pcolors You can set the color of a turtle to be approximately half transparent pure red with the following code set color 255 0 0 125 You can convert between RGB HSB hue saturation brightnes
58. ViSiON Z o ooocnnonoccnnnccccnnnnnooonncncnnnnnnnnnnonnnnnnnncnnnnnnnnnnnnnnncncnannnnos 312 Can agents sense what s in the drawing layer ccccoooooccccncccconononoonncnnncncnnnannoncncnnnnnns 313 I m getting numbers like 0 10000000004 and 0 799999999999 instead of 0 1 and E o E ga e 313 The documentation says that random float 1 might return O but will never return 1 What if want 1 to be included recente errr erra 313 How can keep two turtles from occupying the same patChB o cccccccccnonococoncncncncnanannns 313 How can find out if a turtle is dead errar rrr ea rana 313 Does NetLogo have arrayS Po oococonccccccnonooononnnnccononnnononnnnnnnnnnnnnnnonnnennnnnrnnnnnnnnnnnnnennnnnnnos 313 Does NetLogo have hash tables or associative arrays 2 314 How can use different patch neighborhoods circular Von Neumann Moore A OS 314 How can convert an agentset to a list of agents or vice Versa ccccccconoccconcncncnnnannnnns 314 How d Stop TOS acacia 314 BenaWorSpacersnn ias tail 314 Why are the rows in my BehaviorSpace table results out of order 315 How do measure runs every n tiCkSB ooooooooccccccnnonoconnnnncccnnnnnononnnnnnnncncnnnnnnnnnnnnncncnanannns 315 I m varying a global variable declared in the Procedures tab but it doesn t work AAN LE oa At mnct stata lss Ga E 315 Why are some of my results cut off in ExCel ccccceeseeeeeeeeeseeseseeeeeeeeeeeeessestaaees
59. We don t have automated support for splitting the runs across clusters so you ll need to arrange that yourself Various users are already using NetLogo on clusters with a variety of hardware and software You can seek them out on the NetLogo Users Group Is there any way to recover lost work if NetLogo crashes or freezes Yes NetLogo auto saves files as you are working on them The auto save files can be found in your OS specific temporary directory On most Unix like systems including MacOS that is tmp On Windows XP logs can be found in C Documents and Settings lt user gt Local Settings Temp where lt user gt is the logged in user and on Windows Vista the logs can be found in C Users lt user gt AppData Local Temp The files are named according to the following format autosave_yyyy MM dd HH_mm_ss nlogo where the time and date are the time and date the model was opened Usage When move the speed slider all the way to the right why does my model seem to stop The only way NetLogo can make your model run faster is by updating the view less frequently As you move the speed slider to the right view updates become less and less frequent Since view updates take time that means more speed However fewer updates also means that the updates come farther apart When several seconds pass between updates it may seem like your model has stopped It hasn t It s running at full speed Watch the tick counter If your model u
60. When using the client application you will also need a networked computer with NetLogo installed for each participant When using in classroom settings we also suggest an attached projector for the leader to project the entire simulation to the participants When using client applets you will need to be running a web server on the same machine that you are running the HubNet server in NetLogo Starting an activity You ll find the HubNet activities in NetLogo s Models Library in the HubNet Computer Activities folder We suggest doing a few practice runs of an activity before trying it in front of a class 184 HubNet Guide NetLogo 4 1 2 User Manual 00 Start HubNet Activity Session name Bl 101 M Broadcast server location Open a Computer HubNet model NetLogo will prompt you to enter the name of your new HubNet session This is the name that participants will use to identify this activity Enter a name and press Start NetLogo will open the HubNet Control Center which lets you interact with the HubNet server You as the leader should then notify everyone that they may join To join the activity participants launch the HubNet Client application and enter their name They should see your activity listed and can join your activity by selecting it and pressing Enter If the activity you started is not listed the student can enter the server address manually which can be found in the HubNet Control Center HubNet Control Center
61. a a an vba 246 Matrix modification and math OPeratiONS ccccoonooonccccnnoncnnnnnonnnonnnnnccnnnnnononnnnnnnnnnnnnnnnnnnnnnos 246 MATIX EI EEE E E E E dove Um Ras LARUE LAS E n din E E E 246 MATAN Mira ds 246 MATIX get Dioni to ALEA Alca danada 246 PAE LGD Gacy Rese epee ate aa RD a E e dato IE do TES E po el 246 TA AES EEEE hel eee a e da TE 246 Matrix SeL COMMM Ss ntti A ee ae ee ae Ae ee ee aU 247 MATE SWAD WS ree dotada Ga dlemras arandos E a elias den rae e eta ee gaa Aa a aa 247 Matrix SWAD COIUMNS coccococccocnooonoon non nnnn nono nono nono nono nnnn nn nn rentree nro nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnos 247 NetLogo 4 1 2 User Manual Table of Contents Matrix Extension matrixisetandepO dica id 247 MALFX GIMENSION Sia de 247 MaltrixiSUDIMA T X ooccconoccccnccnnnnccconcnnnncncnnncoconcnnnnnnononcnnononcnnn cano E ETE E arara 247 MAIICUNEsS Cl A T 248 MATIXETMOS a a ca 248 MATHXAMES ClEMOML WISE uc ia 248 Matrix IWS SCA acacia cidad A E rindas dni ss 248 MATIX DIUS vessssyvsiessacersaversandavevevenydeatakvs incas ias SOL TR aham AS CORhRE LARUE LAN AS inaS E da dum oa Seara siga 248 matri nVen orara a tio 248 MATIX TANS posee op ee Ria 248 matrix real elgenValUesS ooooococcoconooonoonoonnnoo nono nono reer nnnnnnnnno nn nnnn nono nro arer trer reer rren areren reenen 249 matrix iMaginary CiQeNValUS ooooocccccnccoonoonoconcoononononnnnnononnnnnnno nono nnnnonnnnnnnnnnnnnnnnnnnnnnnnnnos 249 MatriX EIGENV
62. a model with the System Dynamics Modeler What is the NetLogo System Dynamics Modeler System Dynamics is a type of modeling where you try to understand how things relate to one another It is a little different from the agent based approach we normally use in NetLogo models With the agent based approach we usually use in NetLogo you program the behavior of individual agents and watch what emerges from their interaction In a model of Wolf Sheep Predation for example you provide rules for how wolves sheep and grass interact with each other When you run the simulation you watch the emergent aggregate level behavior for example how the populations of wolves and sheep change over time With the System Dynamics Modeler you don t program the behavior of individual agents Instead you program how populations of agents behave as a whole For example using System Dynamics to model Wolf Sheep Predation you specify how the total number of sheep would change as the total number of wolves goes up or down and vice versa You then run the simulation to see how both populations change over time The System Dynamics Modeler allows you to draw a diagram that defines these populations or stocks and how they affect each other The Modeler reads your diagram and generates the appropriate NetLogo code global variables procedures and reporters to run your System Dynamics model inside of NetLogo Basic Concepts A System Dynamics diagram
63. addition operator that only adds numbers much more efficiently than one that handles several different data types Because addition is such a common operation NetLogo s overall speed is affected The at primitives The observer may no longer use patch at turtles at and BREEDS at Use patch turtles on patch and BREEDS on patch instead Note that patch now rounds its inputs before it only accepted integer inputs Links NetLogo 3 1 had supports for using links to connect turtles to make networks graphs and geometric figures The links were themselves turiles In NetLogo 4 0 instead of links being turtles links are now an independent fourth agent type right alongside observer turtles patches The primitives involving links are no longer considered experimental they are now fully part of the language Models that use the old experimental turtle based link primitives will need to be updated to use link agents The differences are not huge but hand updating is required Links are documented in the Links section of the Programming Guide and in the NetLogo Dictionary entries for the link primitives See the Networks section of the Models Library for example models that use links There are also some link based Code Examples Transition Guide 143 NetLogo 4 1 2 User Manual First you will need to remove any breeds called links if you are only using one type of links then you will not have to use
64. already seen built in turtle variables like color To make a new turtle variable we add a turtles own declaration at the top of the Procedures tab before all the procedures Call it energy turtles own energy to go move turtles eat grass end Let s use this newly defined variable energy to allow the turtles to eat Tutorial 43 Procedures 57 NetLogo 4 1 2 User Manual e Switch to the Procedures tab e Rewrite the go procedure as follows to qo move turtles Sat grass end e Add a new eat grass procedure to eal grass ask turtles if pcolor green set pcolor black set energy energy 10 We are using the i command for the first time Look at the code carefully Each turtle when it runs these commands compares the value of the patch color it is on pcolor to the value for green A turtle has direct access to the variables of the patch it is standing on If the patch color is green the comparison reports t rue and only then will the turtle runs the commands inside the brackets otherwise it skips them The commands make the turtle change the patch color to black and increase its own energy by 10 The patch turns black to signify that the grass at that spot has been eaten and the turtle is given more energy from having just eaten the grass Next let s make the movement of turtles use up some of the turtle s energy e Rewrite move turtles as follows to move turtles ask turtles right random
65. an envelope in GIS space of the sort reported by envelope of The raster dataset is sampled over the area of that envelope e A patch in which case the raster dataset is sampled over the area of the patch e A turtle in which case the raster dataset is sampled at the location of that turtle e A Vertex in which case the raster dataset is sampled at the location of that Vertex If the requested location is outside the area covered by the raster dataset this primitive reports the special value representing not a number which is printed by NetLogo as NaN Using the special not a number value as an argument to primitives that expect a number may cause an error but 294 GIS Extension NetLogo 4 1 2 User Manual you can test the value reported by this primitive to filter out not a number values A value that is not a number will be neither less than nor greater than a number value so you can detect not a number values using the following let value gis raster sample dataset turtle 0 set color to blue if value is a number red if value is not a number ifels value lt 0 or value gt 0 set color blue set color red If the requested location is a point the sample is always computed using the method set by set sampling method If the requested location is an area i e an envelope or patch the sample is computed by taking the average of all raster cells covered by the requested area gis raster world
66. an integer but may also be a floating point number See also set patch size 390 NetLogo Dictionary NetLogo 4 1 2 User Manual patches patches Reports the agentset consisting of all patches patches own patches own var7 This keyword like the globals breed lt breed gt own and turtles own keywords can only be used at the beginning of a program before any function definitions It defines the variables that all patches can use All patches will then have the given variables and be able to use them All patch variables can also be directly accessed by any turtle standing on the patch See also globals turtles own breed lt breeds gt own pcolor PS This is a built in patch variable It holds the color of the patch You can set this variable to make the patch change color All patch variables can be directly accessed by any turtle standing on the patch Color can be represented either as a NetLogo color a single number or an RGB color a list of 3 numbers See details in the Colors section of the Programming Guide See also color pen down pd pen erase pe pen up pu pen down pen erase pen up The turtle changes modes between drawing lines removing lines or neither The lines will always be displayed on top of the patches and below the turtles To change the color of the pen set the color NetLogo Dictionary 391 NetLogo 4 1 2 User Manual of the turtle using set color Note When a t
67. and click on an open spot in the Interface A dialog box will appear Tutorial 43 Procedures 61 NetLogo 4 1 2 User Manual e In the Global variable section of the dialog box type show energy Don t forget to include the question mark in the name See image below MAR ticks 0 count turtles green patches 50 1225 000 Switch Cancel Cok e Now go back to the go procedure using the Procedures tab with the Toolbar e Rewrite the eat grass procedure as follows Lo cal grass ask turtles if pcolor green set pcolor black set energy energy 10 ifelse show energy set label energy set label The eat grass procedure introduces the ifelse command Look at the code carefully Each turtle when it runs these new commands checks the value of show energy determined by the switch If the switch is on comparison is true and the turtle will run the commands inside the first set of brackets In this case it assigns the value for the energy to the label of the turtle If the comparison is false the switch is off then the turtle runs the commands inside the second set of brackets In this case it removes the text labels by setting the label of the turtle to be nothing In NetLogo a piece of text is called a string A string is a sequence of letters and other characters written between double quotes Here we have two double quotes right next to each other with not
68. and over Using a once button like this lets you watch the progress of the model more closely Stopping a forever button is the normal way to stop a model It s safe to pause a model by stopping a forever button then make it go on by pressing the button again You can also stop a model with the Halt item on the Tools menu but you should only do this if the model is stuck for some reason Using Halt may interrupt the model in the middle of an action and as the result the model could get confused e If you like experiment with the setup and go buttons in the Wolf Sheep Predation model Do you ever get different results if you run the model several times with the same settings 32 Tutorial 1 Models NetLogo 4 1 2 User Manual Controlling speed Speed Slider The speed slider allows you to control the speed of a model that is the speed at which turtles move patches change color and so on _ _ _ normal speed When you move the slider to the left the model slows down so there are longer pauses between each tick time step That makes it easier to see what is happening You might even slow the model down so far as to see exactly what a single turtle is doing When you move the speed slider to the right of the center the model will speed up NetLogo will start skipping frames that is it won t update the view at the end of every tick only some ticks Showing the state of the world takes time so showing it less o
69. ask turtle O show one of out links 7 prints highway 1 0 See also breed undirected link breed display display Causes the view to be updated immediately Exception if the user is using the speed slider to fast forward the model then the update may be skipped Also undoes the effect of the no display command so that if view updates were suspended by that command they will resume no display ask turtles jump 10 set color blue set size 5 display 7 turtles move change color and grow with none of their intermediate states visible to the user only their final state Even if no display was not used display can still be useful because ordinarily NetLogo is free to skip some view updates so that fewer total updates take place so that models run faster This command lets you force a view update so whatever changes have taken place in the world are visible to the user ask turtles set color red display ask turtles set color blue 7 turtles turn red then blue use of display forces 7 red turtles to appear briefly Note that display and no display operate independently of the switch in the view control strip that freezes the view See also no display NetLogo Dictionary 337 NetLogo 4 1 2 User Manual distance distance agent Reports the distance from this agent to the given turtle or patch The distance to or a from a patch is measured from the center of the patch Tur
70. ask turtles if energy gt birth energy set energy energy birth energy take away birth energy to give birth hatch 1 set energy birth energy give this birth energy to the offspring end to check death ask turtles if energy lt 0 die removes the turtle if it has no energy left end to regrow grass ask patches 3 out of 100 times the patch color is set to green if random 100 lt 3 set pcolor green end to do plots set current plot Totals which plot we want to use next set current plot pen turtles which pen we want to use next plot count turtles what will be plotted by the current pen set current plot pen grass which pen we want to use next plot count patches with pcolor green what will be plotted by the current pen end Tutorial 3 Procedures 71 72 NetLogo 4 1 2 User Manual Tutorial 3 Procedures Interface Guide This section of the manual walks you through every element of the NetLogo interface in order and explains its function In NetLogo you have the choice of viewing models found in the Models Library adding to existing models or creating your own models The NetLogo interface was designed to meet all these needs The interface can be divided into two main parts NetLogo menus and the main NetLogo window The main window is divided into tabs e Menus e Tabs e Interface Tab Working with Interface Elements The 2D a
71. before trying HubNet for the first time you become familiar with the basics of NetLogo To get started using NetLogo models see Tutorial 1 Running Models in the NetLogo Users Manual HubNet Architecture HubNet simulations are based on a client server architecture The activity leader uses the NetLogo application to run a HubNet activity When NetLogo is running a HubNet activity we refer to it as a HubNet server Participants use a client application to log in and interact with the HubNet server There are two types of HubNet available With Computer HubNet participants run the HubNet Client application on computers connected by a regular computer network or they use a Java applet in a web browser In Calculator HubNet created in conjunction with Texas Instruments participants use Texas Instruments graphing calculators as clients which communicate via the Tl Navigator system We hope to add support for other types of clients such as cell phones and PDA s Personal Digital Assistants HubNet Guide 183 NetLogo 4 1 2 User Manual Computer HubNet Activities The following activities are available in the Models Library in the Computer HubNet Activities folder Information on how to run the models and activities can be found in the Information Tab of each model Additional discussion of educational goals and ways to incorporate many of the activities into your classroom in the Participatory Simulations Guide on the Participatory Simulatio
72. begin a reporter procedure The body of the procedure should use report to report a value for the procedure See report to report average a b report a b 2 end to report absolute value number ifelse number gt 0 report number report number end to report first turtle report who 0 reports true or false end towards towards agent Reports the heading from this agent to the given agent If wrapping is allowed by the topology and the wrapped distance around the edges of the world is shorter towards will use the wrapped path 418 NetLogo Dictionary NetLogo 4 1 2 User Manual Note asking for the heading from an agent to itself or an agent on the same location will cause a runtime error set heading towards turtle 1 7 same as face turtle 1 See also face towardsxy towardsxy x y Reports the heading from the turtle or patch towards the point x y If wrapping is allowed by the topology and the wrapped distance around the edges of the world is shorter towardsxy will use the wrapped path Note asking for the heading to the point the agent is already standing on will cause a runtime error See also facexy turtle turtle number lt breed gt number Reports the turtle with the given who number or nobody if there is no such turtle For breeded turtles you may also use the single breed form to refer to them ask turtle 5 set color red turtle with who nu
73. breeds at all If you are using multiple types of links see undirected link breed and directed 1ink breed Commands and reporters that contain the word links like __create 1inks with etc will automatically be converted to the new form without underscores create 1inks with However primitives that use a different breed name such as edges will not be converted You will need to remove the underscores by hand and unless you are declaring a link breed with that name you will need to change the breed designation to links The commands remove link s with from to no longer exist Instead you should ask the links in question to die For example ask turtle 0 __remove links with link neighbors becomes ask turtle 0 ask my links die Several of the layout commands have slightly different inputs the first two inputs are generally a turtle agentset and a link agentset to perform the layout on See the dictionary entries for details layout spring layout magspring layout radial layout tutte You may also need to rearrange the declaration of turtles own variables since links were once actually turtles Any variables that apply to links should be moved into a 1inks own block Since links are no longer turtles they no longer have the built in turtle variables though some of the link variables are the same such as color and label If you formerly used the location of link turtles you will now need to calculate the midp
74. by the random seed as well so model runs can be reproducible In addition to the uniformly distributed random integers and floating point numbers generated by random and random float NetLogo also offers several other random distributions See the dictionary entries for random normal random poisson random exponential and random gamma Auxiliary generator Code run by buttons or from the command center uses the main random number generator Code in monitors uses an auxiliary random generator so even if a monitor does a calculation that uses random numbers the outcome of the model is not affected The same is true of code in sliders Local randomness You may want to explicitly specify that a section of code does not affect the state of the main random generator so the outcome of the model is not affected The with local randomness command is provided for this purpose See its entry in the NetLogo Dictionary for more information Turtle shapes In NetLogo turtle shapes are vector shapes They are built up from basic geometric shapes squares circles and lines rather than a grid of pixels Vector shapes are fully scalable and rotatable NetLogo caches bitmap images of vector shapes size 1 1 5 and 2 in order to speed up execution A turile s shape is stored in its shape variable and can be set using the set command New turtles have a shape of default The set default shape primitive is useful for changing the default turtle s
75. by the command are determined by the gogo talk to output ports command Note that this is different from gogo output port reverse because thisway and thatway will always be the same direction provided the connector s polarity is the same gogo talk to output ports gogo talk to output ports output portlist This command will set the corresponding output ports as active They will be the ones affected by the commands such as gogo output port on and gogo output port off The user can talk to one or multiple ports at the same time Output ports are typically connected to motors but you could also use bulbs LEDs and relays Output ports are identified by one letter names a b c and d Examples 7 talk to all output ports gogo talk to output ports a b er ad 7 will give power to all output ports gogo output port on 5 talk to output ports A and D gogo talk to output ports a da 7 will turn off output ports A and D The other output ports will keep their current state gogo output port off gogo talk to output ports c b 5 turn off remaining output ports gogo output port off NetLogoLab and the GoGo Board Extension 271 NetLogo 4 1 2 User Manual gogo ping gogo ping Checks the status of GoGo board This is mostly used to make sure the board is connected to the correct serial port lt reports true if the GoGo Board responds to a diagnostic message and false otherwi
76. called birth energy e Then inside of cat grass make this change to cal grass 68 Tutorial 43 Procedures NetLogo 4 1 2 User Manual ask turtles if pcolor green set pcolor black set energy energy energy from grass ifelse show energy set label energy set label end e And inside of reproduce make this change to reproduce ask turtles if energy gt birth energy set energy energy birth energy hatch 1 set energy birth energy Finally what other slider could you add to vary how often grass grows back Are there rules you can add to the movement of the turtles or to the newly hatched turtles that happen only at certain times Try writing them What s next So now you have a simple model of an ecosystem Patches grow grass turtles wander eat the grass reproduce and die You have created an interface containing buttons sliders switches monitors and plots You ve even written a series of procedures to give the turtles something to do That s where this tutorial leaves off If you d like to look at some more documentation about NetLogo the Interface Guide section of the manual walks you through every element of the NetLogo interface in order and explains its function For a detailed description and specifics about writing procedures refer to the Programming Guide All of the primitives are listed and described in the the NetLogo Dictionary Also you can continue expe
77. classes src IntegerList java src SampleExtension java You will need to change the classpath argument to point to the NetLogo jar file from your NetLogo installation This command line will compile the java and put the class files in the classes subfolder Then create a JAR containing the resulting class files and the manifest For example jar cvfm example jar manifest txt C classes Extensions Guide 233 NetLogo 4 1 2 User Manual For information about manifest files JAR files and Java tools see java sun com 5 Use your extension in a model To use our example extension put the example folder in the NetLogo extensions folder or in the same directory as the model that will use the extension At the top of the Procedures tab write extensions example Now you can use example first n integers just like it was a built in NetLogo reporter For example select the Interface tab and type in the Command Center observer gt show example first n integers 5 observer 0 1 2 3 4 Scala Tutorial Now let s rewrite the extension in Scala First you ll need to make sure you are using exactly the right version of Scala Extensions written in Scala must be compiled with the specific Scala build dated 2009 04 16 revision r17517 available here scala 2 8 0 r17517 zip We apologize for the inconvenience of requiring this particular Scala version in a future version of NetLogo we plan to require the released version of Scal
78. condition This lets you do model runs of varying length ending each run when a certain condition becomes true For example suppose you wanted each run to last until there were no more turtles Then you would enter not any turtles If you want the length of runs to all be of a fixed length just leave this blank The run may also stop because the go commands use the stop command in the same way that stop can be used to stop a forever button The stop command may be used directly in the go commands or in a procedure called directly by the go commands The intent is that the same go procedure should work both in a button and in a BehaviorSpace experiment Note that the step in which stop is used is considered to have been aborted so no results will be recorded for that step Therefore the stopping test should be at the beginning of the go commands or procedure not at the end Final commands These are any extra commands that you want run once when the run ends Usually this is left blank but you might use it to call the export wor Ld command or record the results of the run in some other way Time limit This lets you set a fixed maximum length for each run If you don t want to set any maximum but want the length of the runs to be controlled by the stop condition instead enter 0 Special primitives for BehaviorSpace experiments Currently there is only one behaviorspace run number The run number reported by this primitive match
79. designer of this simulation thought that groups at parties don t just form randomly The groups are determined by how the individuals at the party behave The designer chose to focus on a particular variable called tolerance 28 Sample Model Party NetLogo 4 1 2 User Manual Tolerance is defined here as the percentage of people of the opposite sex an individual is comfortable with If the individual is in a group that has a higher percentage of people of the opposite sex than their tolerance allows then they become uncomfortable and leave the group to find another group For example if the tolerance level is set at 25 then males are only comfortable in groups that are less than 25 female and females are only comfortable in groups that are less than 25 male As individuals become uncomfortable and leave groups they move into new groups which may cause some people in that group to become uncomfortable in turn This chain reaction continues until everyone at the party is comfortable in their group Note that in the model tolerance is not fixed You the user can use the tolerance slider to try different tolerance percentages and see what the outcome is when you start the model over again How to start over 1 If the go button is pressed black then the model is still running Press the button again to stop it 2 Adjust the tolerance slider to a new value by dragging its red handle 3 Press the s
80. dict gt 2 print table get dict turtle gt cute print table get dict leopard gt error print table keys dict gt turtle bunny Array primitives array from list array item array set array length array to list array from list array from list list Reports a new array containing the same items in the same order as the input list array item array item array index Reports the item in the given array with the given index ranging from zero to the length of the array minus one array set array set array index value Sets the item in the given array with the given index ranging from zero to the length of the array minus one to the given value 240 Array and Table Extensions NetLogo 4 1 2 User Manual Note that unlike the replace item primitive for lists a new array is not created The given array is actually modified array length array length array Reports the length of the given array that is the number of items in the array array to list array to list array Reports a new list containing the same items in the same order as the given array Table Primitives table clear table from list table get table has key table keys table length table make table put table remove table to list table clear table clear table Removes all key value pairs from table table from list table from list list Reports a new table with the contents of list list must be a list of two element list
81. e NetLogo s local variables and inputs to procedures are lexically scoped not dynamically scoped e NetLogo has no word data type what Lisp calls symbols Eventually we may add one but since it is seldom requested it may be that the need doesn t arise much in agent based modeling We do have strings In most situations where traditional Logo would use words we simply use strings instead For example in Logo you could write see spot run a list of words but in NetLogo you must write see spot run a string or see spot run a list of strings instead e NetLogo s run command works on strings not lists since we have no word data type and does not permit the definition or redefinition of procedures e Control structures such as if and while are special forms not ordinary functions You can t define your own special forms so you can t define your own control structures NetLogo s run command is no help here e As in most Logos functions as values are not supported Most Logos provide similar if less general functionality though by allowing passing and manipulation of fragments of source code in list form NetLogo s capabilities in this area are presently limited A few of our built in special forms use UCBLogo style templates to accomplish a similar purpose for example sort by length 21 lt length 22 string list In some circumstances using run and runresult instead is workable but unlike most Logos they operate
82. efficiency However patches not covered by the raster are assigned values of not a number in the same way that raster sample reports values for locations outside the raster Drawing Primitives gis drawing color gis drawing color Reports the color used by the GIS extension to draw vector features into the NetLogo drawing layer Color can be represented either as a NetLogo color a single number between zero and 140 or an RGB color a list of 3 numbers See details in the Colors section of the Programming Guide 296 GIS Extension NetLogo 4 1 2 User Manual gis set drawing color gis set drawing color color Sets the color used by the GIS extension to draw vector features into the NetLogo drawing layer Color can be represented either as a NetLogo color a single number between zero and 140 or an RGB color a list of 3 numbers See details in the Colors section of the Programming Guide gis draw gis draw vector data line thickness Draws the given vector data to the NetLogo drawing layer using the current GIS drawing color with the given line thickness The data may consist either of an entire VectorDataset or a single VectorFeature This primitive draws only the boundary of polygon data and for point data it fills a circle with a radius equal to the line thickness gis fill gis fill vector data line thickness Fills the given vector data in the NetLogo drawing layer using the current GIS drawing color using the gi
83. envelope gis raster world envelope RasterDataset x y Reports the GIS envelope needed to match the boundaries of NetLogo patches with the boundaries of cells in the given raster dataset This envelope could then be used as an argument to set transformation ds There may be more cells in the dataset than there are patches in the NetLogo world In that case you will need to select a subset of cells in the dataset by specifying which cell in the dataset you want to match with the upper left corner of the NetLogo world Cells are numbered from left to right and from top to bottom beginning with zero So the upper left cell is 0 0 and the bottom right cell is gis width of dataset 1 gis height of dataset 1 gis create raster gis create raster width height envelope Creates and reports a new empty raster dataset with the given number of columns and rows covering the given envelope gis resample gis resample RasterDataset envelope width height Reports a new dataset that consists of the given RasterDataset resampled to cover the given envelope and to contain the given number of columns and rows If the new raster s cells are smaller than the existing raster s cells they will be resampled using the method set by set sampling method If the new cells are larger than the original cells they will be sampled using the NEAREST_NEIGHBOR method gis convolve GIS Extension 295 NetLogo 4 1 2 User Manual gis convolv
84. everyone See also map reduce first first list first string On a list reports the first Oth item in the list On a string reports a one character string containing only the first character of the original string floor floor number Reports the largest integer less than or equal to number show floor 4 5 gt 4 348 NetLogo Dictionary NetLogo 4 1 2 User Manual show floor 4 5 gt 5 See also ceiling round precision follow follow turtle gt Similar to ride but in the 3D view the observer s vantage point is behind and above turtle See also follow me ride reset perspective watch subject follow me follow me Asks the observer to follow this turtle See also follow foreach foreach list commands foreach ist1 commands With a single list runs commanas for each item of list In commanas use to refer to the current item of list foreach 1 1 2 2 2 6 show word gt round 2 gt 1 1 gt 1 gt 2 2 gt 2 gt 2 6 gt 3 With multiple lists runs commands for each group of items from each list So they are run once for the first items once for the second items and so on All the lists must be the same length In commands use 21 through n to refer to the current item of each list Some examples make this clearer foreach 1 2 3 2 4 6 show word the sum is 21 22 gt the sum is 3 gt the sum
85. given string using wildcard matching which matches any number of occurrences of any characters If the VectorFeatures are polygons you can also apply the values of a particular property of the dataset s features to a given patch variable There are also several things you can do with a VectorFeature from a VectorDataset ask it for a list of vertex lists ask it for a property value by name ask it for its centroid center of gravity and ask GIS Extension 279 NetLogo 4 1 2 User Manual for a subset of a given agentset whose agents intersect the given VectorFeature For point data each vertex list will be a one element list For line data each vertex list will represent the vertices of a line that makes up that feature For polygon data each vertex list will represent one ring of the polygon and the first and last vertex of the list will be the same The vertex lists are made up of values of type Vertex and the centroid will be a value of type Vertex as well There are a number of operations defined for RasterDatasets as well Mostly these involve sampling the values in the dataset or re sampling a raster to a different resolution You can also apply a raster to a given patch variable and convolve a raster using an arbitrary convolution matrix Known issues The values of type RasterDataset VectorDataset VectorFeature and Vertex are not handled properly by export world and import world To save datasets you must use the gi
86. gt number create ordered lt breeds gt number commands Creates number new turtles New turtles start at position 0 0 are created with the 14 primary colors and have headings from 0 to 360 evenly spaced If the create ordered lt breeds gt form is used the new turtles are created as members of the given breed If commands are supplied the new turtles immediately run them This is useful for giving the new turtles a different color heading or whatever The new turtles are created all at once then run one at a time in random order cro 100 fa 10 7 makes an evenly spaced circle create lt breed gt to create lt breeds gt to create lt breed gt from create lt breeds gt from create lt breed gt with create lt breeds gt with create link to create links to create link from create links from create link with create links with 332 NetLogo Dictionary NetLogo 4 1 2 User Manual create lt breed gt to turtle create lt breed gt to turtle commands create lt breed gt from turtle create lt breed gt from turtle commands create lt breed gt with turile create lt breed gt with turtle commands create lt breeds gt to turtleset create lt breeds gt to turtleset commands create lt breeds gt from turtleset create lt breeds gt from turtleset commands create lt breeds gt with turtleset create lt breeds gt with turtleset commands create link to turtle create link to tur
87. heading won t change facexy facexy number number Set the caller s heading towards the point x y If wrapping is allowed by the topology and the wrapped distance around the edges of the world is shorter and wrapping is allowed facexy will use the wrapped path If the caller is on the point x y the caller s heading won t change file at end file at end Reports true when there are no more characters left to read in from the current file that was opened previously with file open Otherwise reports false file open my file txt print file at end gt false Can still read in more characters print file read line gt This is the last line in file print file at end NetLogo Dictionary 343 NetLogo 4 1 2 User Manual gt true We reached th nd of the file See also file open file close all file close file close Closes a file that has been opened previously with file open Note that this and file close all are the only ways to restart to the beginning of an opened file or to switch between file modes If no file is open does nothing See also file close all file open file close all file close all Closes all files if any that have been opened previously with file open See also file close file open file delete file delete string Deletes the file specified as string string must be an existing file with writable permission by the user Also the file cannot be open Use the
88. iba RARA ci orden Coordinate System Prine 2d aaa PERA PPP E QiS SEt traNSfOrMAtiON AS cccccceesecscceceeeeceesennaeeeeeeeesseeseceeeeeeeeeeeseseseeeeeeeeessssnnaaees ais l ad dataSel sita iii ca OIS Siore datasSet ti A A LR A da OS YOON year a ah Fold E ANET Qis patch dataset ooococcccnnccnnccnncnnnnnnnnnnnnnnnnnnnnnnnnrnnrrnn orar erre erre gis turtle datada OISMINK20ataS Cbs cvscoseavedsvavievs e da Sidon Tone E ERES Deed A pa da aa VectorDataset Primitives si RE eLo ARA POON as decano Rad RD INE E uesdasnesdinuats ARS O ais satelite AER SIS AOL cesar nora pads us a a a AE E O GEL o a ap CIS CONTO NAAA A dad Rea IS OCA ION Odo dIS Property Vall iaa A A ASTM TOA rt oa USOS L e 6 id A RR O GIS TING GFE atera SUR UP RAR RS de CUS NAC LARS eo ides a SS EES xii NetLogo 4 1 2 User Manual Table of Contents GIS Extension gis c nt ined By Across minis na best dai babu q Qd a SU Da poem 289 gis have relationship ara aida 290 E E A A A E aac tes 291 DIS INSECTO diia iii 292 RasterDataset Primitives ita iaa 292 ISI RA A 293 A O EN RA 293 gls raster Valli a 293 OlS SOETASterva lll ica pS Ta id 293 A E nt rude ee e e a 293 CS TT ANIMALS OLS coa san A a a A 293 is sampling method Of iaa 293 gis set sampling method raras rear ease Taa a a 294 gisiraster SaMpIle ciais dei dedos arated anes adi Wena tala Weave a 294 gis raster world envelope erre rear rr rre 295 gis create
89. in source or binary form for any purpose with or without fee is hereby granted provided that the following conditions are met 1 Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer 2 Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided with the distribution 3 Neither the name of the EPFL nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE MersenneTwisterFast For random number generation NetLogo uses the MersenneTwisterFast clas
90. is akin to matrix division That is the goal is to find a matrix B such that A B C For simple linear systems C and B can both be 1 dimensional matrices e vectors If A is not a square matrix then a least squares solution is returned 7 To solve the set of equations x 3y 10 and 7x 4y 20 7 We make our A matrix 1 3 7 4 and our C matrix 10 20 let A matrix from row list 1 3 7 4 let C matrix from row list 10 20 print matrix solve A C gt matrix 4 11 2 0000000000000004 13 NOTE as you can see the the results may be only approximate 5 In this case the true solution should be x 4 and y 2 matrix forecast linear growth matrix forecast linear growth data list Reports a four element list of the form forecast constant slope R2 The forecast is the predicted next value that would follow in the sequence given by the data list input based on a linear trend line Normally data list will contain observations on some variable Y from time t 0 to time t n 1 where n is the number of observations The forecast is the predicted value of Y att n The constant and slope are the parameters of the trend line Y constant slope t The R value measures the goodness of fit of the trend line to the data with an R2 1 being a perfect fit and an R of 0 indicating no discernible trend Linear growth assumes that the variable Y grows by a constant absolute amount each
91. itself is always serial regardless of the context in which it is used however In our own Models Library models that make use of this concurrency are rare A prominent example though is Termites which uses a concurrent turtle forever button Tick counter NetLogo now has a built in tick counter for representing the passage of simulated time You advance the counter by one using the tick command If you need to read its value there s a reporter called ticks The clear a11 command resets the tick counter so does reset ticks In most models the tick counter will be integer valued but if you want to use smaller increments of time you can use the tick advance command to advance the tick counter by any positive amount including fractional amounts Some Models Library models that use tick advance are Vector Fields and the GasLab models The value of the tick counter is displayed in the toolbar at the top of the Interface tab You can use the Settings button in the toolbar to hide the tick counter or change the word ticks to something else View update modes In the past NetLogo always tried to update the view about 20 times a second We re now calling that continuous view updates The biggest problem with it was that you usually want updates to happen between model ticks not in the middle of a tick so we had a checkbox on buttons that by default forced a display update after every button iteration That made sure updates hap
92. limit the rate at which they send messages to conserve bandwidth for Windows users bundle Java 6 Update 22 GIS extension now includes license information e API changes extensions API deprecated runCommand and runReporter methods controlling API added possibleViewUpdate and tickCounterChanged methods to NetLogoListener logging changes to the tick counter are now logged exactly as if ticks was a global variable Version 4 1 1 August 2010 e additions new matrix extension for matrix manipulation new behaviorspace run number reporter new biology model Flocking Vee Formations new Donate item on Help menu e fixes fixed models Dining Philosophers Sandpile 3D Shepherds Connected Chemistry 8 Gas Particle Sandbox on Windows bundle Java 6 Update 21 fixed embedding API bug where two models could not be embedded in the same window What s New 13 NetLogo 4 1 2 User Manual fixed bug where in worlds with certain unusual combinations of settings passing specific unusual inputs involving patch boundaries to primitives including patch at and patch at heading and distance could cause a Java exception fixed bug causing some models with plots to intermittently produce spurious error messages fixed we hope intermittent bug where editing code in the procedures tab or command center could cause spurious ArrayIndexOutOfBoundsException errors fixed bug in 2D view where partially transparent turtle
93. link set are springs and the turtles are repelling each other Turtles that are connected by links in ink set but not included in turtle set are treated as anchors and are not moved spring constant is a measure of the tautness of the spring It is the resistance to change in their length spring constant is the force the spring would exert if it s length were changed by 1 unit spring length is the zero force length or the natural length of the springs This is the length which all springs try to achieve either by pushing out their nodes or pulling them in repulsion constant is a measure of repulsion between the nodes It is the force that 2 nodes at a distance of 1 unit will exert on each other The repulsion effect tries to get the nodes as far as possible from each other in order to avoid crowding and the spring effect tries to keep them at about a certain distance from the nodes they are connected to The result is the laying out of the whole network in a way which highlights relationships among the nodes and at the same time is crowded less and is visually pleasing The layout algorithm is based on the Fruchterman Reingold layout algorithm More information about this algorithm can be obtained here to make a triangle set default shape turtles circle NetLogo Dictionary 367 NetLogo 4 1 2 User Manual ert 3 ask turtle 0 create links with other turtles ask turtle 1 create link with turtle 2 repeat 30
94. lower left corner of the world you define the right and top positive boundaries Edge mode allows you to place the origin along one of the edges x or y then define the far boundary in that direction and both boundaries in the other For example if you select edge mode along the bottom of the world you must also define the top boundary as well as the left and the right Finally Custom mode allows the user to place the origin at any location in the world though patch O O must still exist in the world As you change the settings you will notice that the changes you make are reflected in the preview on the right side of the panel which shows the origin and the boundaries The width and height of the world are displayed below the preview Also below the preview there are two checkboxes the world wrap settings These allow you to control the topology of the world Notice when you click the check boxes the preview indicates which directions allow wrapping and the name of the topology is displayed next to the world dimensions See the Topology Section of the Programming Guide for more information The view settings allow you to customize the look of the view without changing the world Changing view settings will never force a world reset To change the size of the 2D View adjust the Patch Size setting measured in pixels This does not change the number of patches only how large the patches appear in the 2D View Note that the patch size
95. mode mode 1 352 NetLogo Dictionary NetLogo 4 1 2 User Manual For histogramming purposes the plot s X range is not considered to include the maximum X value Values equal to the maximum X will fall outside of the histogram s range histogram color of turtles draws a histogram showing how many turtles there are 77 Of each color home home This turtle moves to the origin 0 0 Equivalent to setxy 0 0 hsb hsb hue saturation brightness Reports a RGB list when given a color in HSB format Hue saturation and brightness are integers in the range 0 255 The RGB list contains three integers in the same range See also rgb hubnet broadcast hubnet broadcast tag name value This broadcasts value from NetLogo to the variable in the case of Calculator HubNet or interface element in the case of Computer HubNet with the name tag name to the clients See the HubNet Authoring Guide for details and instructions hubnet broadcast clear output hubnet broadcast clear output This clears all messages printed to the text area on every client See also hubnet broadcast message hubnet send clear output hubnet broadcast message hubnet broadcast message value This prints the value in the text area on each client This is the same functionality as the Broadcast Message button in the HubNet Control Center See also hubnet send message NetLogo Dictionary 353 NetLogo 4 1 2 User Manual hubnet broadcast view hubnet br
96. mode to none if they were previously tied together If the link is an undirected link then it will untie end7 from end2 as well lt does not remove the link between the two turtles 422 NetLogo Dictionary NetLogo 4 1 2 User Manual See also tie See the Tie section of the Programming Guide for more details uphill uphill4 uphill patch variable as patch variable Moves the turtle to the neighboring patch with the highest value for patch variable If no neighboring patch has a higher value than the current patch the turtle stays put If there are multiple patches with the same highest value the turtle picks one randomly Non numeric values are ignored uphill considers the eight neighboring patches uphill4 only considers the four neighbors Equivalent to the following code assumes variable values are numeric move to patch here go to patch center let p max one of neighbors patch variablel or neighbors4 1f patch variable of p gt patch variable face p move to p Note that the turtle always ends up on a patch center and has a heading that is a multiple of 45 uphill or 90 uphill4 See also downhill downhill4 user directory user directory Opens a dialog that allows the user to choose an existing directory on the system It reports a string with the absolute path or false if the user cancels set current directory user directory Assumes the user will choose a directory user file use
97. model Here are the monitors in Wolf Sheep Predation time ticks sheep wolves grass 4 0 0 0 0 The monitor labeled time ticks tells us how much time has passed in the model The other monitors show us the population of sheep and wolves and the amount of grass Remember the amount of grass is divided by four to keep the plot from getting too tall The numbers displayed in the monitors update continuously as the model runs whereas the plots show you data from the whole course of the model run Note that NetLogo has also another kind of monitor called agent monitors These will be introduced in Tutorial 2 Controlling the View If you look at the interface tab you ll see a strip of controls along the top edge in the toolbar These controls change various aspects of the view Let s experiment with the effect of these controls e Press setup and then go to start the model running e As the model runs move the speed slider to the left What happens This slider is helpful if a model is running too fast for you to see what s going on in detail e Move the speed slider to the middle e Try moving the speed slider to the right e Now try checking and unchecking the view updates checkbox What happens Fast forwarding the model and turning off view updates are useful if you re impatient and want a model to run faster Fast forwarding moving the speed slider to the right drops view updates so the
98. model more and more many of your preconceived ideas about various phenomena will be challenged For example a surprising result of the Party model is that even if tolerance is relatively high a great deal of separation between the sexes occurs This is a classic example of an emergent phenomenon where a group pattern results from the interaction of many individuals This idea of emergent phenomena can be applied to almost any subject What other emergent phenomena can you think of To see more examples and gain a deeper understanding of this concept and how NetLogo helps learners explore it you may wish to explore NetLogo s Models Library It contains models that demonstrate these ideas in systems of all kinds For a longer discussion of emergence and how NetLogo helps learners explore it see Modeling Nature s Emergent Patterns with Multi agent Languages Wilensky 2001 What s Next The section of the User Manual called Tutorial 1 Running Models goes into more detail about how to use the other models in the Models Library If you want to learn how to explore the models at a deeper level Tutorial 2 Commands will introduce you to the NetLogo modeling language Eventually you ll be ready for Tutorial 3 Procedures where you can learn how to alter and extend existing models to give them new behaviors and build your own models 30 Sample Model Party Tutorial 1 Models If you read the Sample Model Party section y
99. name Clears watch or follow sent directly to the client The view perspective will revert to the server perspective See also hubnet send watch hubnet send follow hubnet send hubnet send string tag name value hubnet send list of strings tag name value For Calculator HubNet this primitive acts in exactly the same manner as hubnet broadcast We plan to change this in a future version of NetLogo For Computer HubNet it acts as follows For a string this sends value from NetLogo to the tag tag name on the client that has string for its user name For a list of strings this sends value from NetLogo to the tag tag name on all the clients that have a user name that is in the list of strings Sending a message to a non existent client using hubnet send generates a hubnet exit message See the HubNet Authoring Guide for details hubnet send clear output hubnet send clear output string hubnet send clear output list of strings This clears all messages printed to the text area on the given client or clients specified in the string or list of strings See also hubnet send message hubnet broadcast clear output hubnet send follow hubnet send follow client name agent radius Tells the client associated with client name to follow agent showing a radius sized Moore neighborhood around the agent 356 NetLogo Dictionary NetLogo 4 1 2 User Manual See also hubnet send watch hubnet reset perspective hubnet send messag
100. now use tick based updates Even for models that would normally be set to tick based updates it may be useful to switch to continuous updates temporarily for debugging purposes Seeing what s going on within a tick instead of only seeing the end result of a tick could help with troubleshooting If you switch your model to use tick based updates you ll also need to add the tick command to your code otherwise the view won t update Note that the view still always updates when a button pops up or a command entered in the command center finishes though So it s not like the view will just stay frozen indefinitely How to make a model use ticks and tick based updates Here are the steps to follow to convert your model to use ticks and tick based updates in NetLogo 4 0 1 In the Interface tab toolbar on the right hand side where it says update view change the setting from continuously to on ticks 2 Add the tick command to your go procedure at or near the end In Models Library models we always put tick after the agents move but before any plotting commands That s because the plotting commands might contain something like plotxy ticks and we want the new value of the tick counter used not the old one Most models don t refer to the tick counter in their plotting commands but nonetheless for consistency and to avoid mistakes we suggest always putting tick before the plotting commands Some models will require some a
101. observer is in watch mode it tracks the movements of one turtle without moving In both views you will see a spotlight appear on the subject and in the 3D view the observer will turn to face the subject To determine which agent is the focus you can use the subject reporter Code Example Perspective Example Drawing The drawing is a layer where turtles can make visible marks In the view the drawing appears on top of the patches but underneath the turtles Initially the drawing is empty and transparent You can see the drawing but the turtles and patches can t They can t sense the drawing or react to it The drawing is just for people to look at Turtles can draw and erase lines in the drawing using the pen down and pen erase commands When a turtle s pen is down or erasing the turtle draws or erases a line behind it whenever it moves The lines are the same color as the turtle To stop drawing or erasing use pen up 126 Programming Guide NetLogo 4 1 2 User Manual Lines drawn by turtles are normally one pixel thick If you want a different thickness set the pen size turtle variable to a different number before drawing or erasing In new turtles the variable is set to 1 Lines made when a turtle moves in a way that doesn t fix a direction such as with set xy or move to the shortest path line that obeys the topology will be drawn Here s some turtles which have made a drawing over a grid of randomly shaded patches
102. of a NetLogo model First use the movie start command to start a new movie The filename you provide should end with mov the extension for QuickTime movies To add a frame to your movie use either movie grab view Of movie grab interface depending on whether you want the movie to show just the current view or the entire Interface tab In a single movie you must use only one movie grab primitive or the other you can t mix them When you re done adding frames use movie close 77 export a 30 frame movie of the view setup movie start out mov movie grab view show the initial state repeat 30 go movie grab view movie close By default a movie will play back at 15 frames per second To make a movie with a different frame rate call movie set frame rate with a different number of frames per second You must set the frame rate after movie start but before grabbing any frames To check the frame rate of your movie or to see how many frames you ve grabbed call movie status which reports a string that describes the state of the current movie To throw away a movie and delete the movie file call movie cancel Programming Guide 125 NetLogo 4 1 2 User Manual Code Example Movie Example Movies can only be generated from the NetLogo GUI not when running headless or by background runs in a parallel BehaviorSpace experiment NetLogo movies are exported as uncompressed QuickTime files To play a QuickTim
103. of the NetLogo world has four potential values torus box vertical cylinder or horizontal cylinder The topology is controlled by enabling or disabling wrapping in the x or y directions The default world is a torus as were all NetLogo worlds before NetLogo 3 1 A torus wraps in both directions meaning that the top and bottom edges of the world are connected and the left and right edges are connected So if a turtle moves beyond the right edge of the world it appears again on the left and the same for the top and bottom A box does not wrap in either direction The world is bounded so turtles that try to move off the edge of the world cannot Note that the patches around edge of the world have fewer than eight neighbors the corners have three and the rest have five Horizontal and vertical cylinders wrap in one direction but not the other A horizontal cylinder wraps vertically so the top of the world is connected to the bottom but the left and right edges are bounded A vertical cylinder is the opposite it wraps horizontally so the left and right edges are connected but the top and bottom edges are bounded Code Example Neighbors Example Since NetLogo 3 0 there have been settings to enable wrapping visually so if a turtle shape extends past an edge part of the shape will appear on the other edge of the view Turtles themselves are points that take up no space so they cannot be on both sides of the world at once but in the view the
104. on a massively parallel supercomputer called the Connection Machine A few years later 1994 a single threaded version was developed for the Macintosh computer That version eventually became MacStarLogo StarLogoT 1997 developed at the Center for Connected Learning and Computer Based Modeling CCL is essentially an extended version of MacStarLogo with many additional features and capabilities Since then two multi platform Java based multi agent Logos have been developed NetLogo from the CCL and a Java based version of StarLogo from MIT The NetLogo language and environment differ in many respects from MIT StarLogo s Both languages were inspired by the original StarLogo but were redesigned in different ways NetLogo s design was driven by the need to revise and expand the language so it is easier to use and more powerful and by the need to support the HubNet architecture NetLogo incorporates almost all of the extended functionality of our earlier StarLogoT as well as many newer features Under what license is NetLogo released Is the source code available The license is given in the Copyright section of the NetLogo User Manual as well as in the application s about box and the README file accompanying the download A quick summary of the license is that use is unrestricted including commercial use but there are some restrictions on redistribution and or modification unless you contact Uri Wilensky to arrange different terms
105. other operating systems Interface 361 ititled a Information 32 focedures BESMI 7 Procedures 363 foo nls 384 Includes y Caution The includes facility is new and experimental Nonetheless we think some users will find it useful Interface Guide 91 NetLogo 4 1 2 User Manual Indent Automatically When the Indent Automatically checkbox is selected NetLogo will automatically attempt to align your code in an easy to read format For example when you open a set of square brackets perhaps after an if statement NetLogo will automatically add spaces so that the following lines of code are two space further indented than the bracket When you close the square brackets the closing bracket will be lined up with the matching open bracket to setup clear all create turtles 5 i set color red set shape circle end NetLogo will try to indent the code as you type but you can also press the tab key anywhere on any line to manually ask NetLogo to indent the line properly or you can highlight entire regions of code and press the tab key to re indent 92 Interface Guide Programming Guide This section describes the NetLogo programming language The Code Example models mentioned throughout can be found in the Code Examples section of the Models Library e Agents e Procedures e Variables e Colors e Ask e Agentsets e Breeds e Buttons e Lists e Math e Random Numbers e Turtle Shapes e L
106. output area then the Command Center is used P patch patch xcor ycor Given the x and y coordinates of a point reports the patch containing that point The coordinates are absolute coordinates they are not computed relative to this agent as with patch at If x and y are integers the point is the center of a patch If x or y is not an integer rounding to the nearest integer is used to determine which patch contains the point If wrapping is allowed by the topology the given coordinates will be wrapped to be within the world If wrapping is not allowed and the given coordinates are outside the world reports nobody ask patch 3 4 set pcolor green 7 patch with pxcor of 3 and pycor of 4 turns green show patch 1 2 3 7 7 prints patch 1 4 note rounding show patch 18 19 77 Supposing min pxcor and min pycor are 17 7 and max pxcor and max pycor are 17 7 in a wrapping topology prints patch 17 16 in a non wrapping topology prints nobody See also patch at patch ahead patch ahead distance Reports the single patch that is the given distance ahead of this turtle that is along the turtle s current heading Reports nobody if the patch does not exist because it is outside the world ask patch ahead 1 set pcolor green 388 NetLogo Dictionary NetLogo 4 1 2 User Manual turns the patch 1 in front of this turtle ae green note that this might be the same patch He the turtle is standing on
107. own cars bikes list list value value2 list value Reports a list containing the given items The items can be of any type produced by any kind of reporter show list random 10 random 10 gt 4 9 77 or similar list show list 5 gt 5 show list random 10 1 2 3 random 10 gt 4 1 2 3 9 77 or similar list In In number Reports the natural logarithm of number that is the logarithm to the base e 2 71828 See also e log log log number base Reports the logarithm of number in base base show log 64 2 gt 6 NetLogo Dictionary 371 NetLogo 4 1 2 User Manual See also In loop loop commands Runs the list of commands forever or until the current procedure exits through use of the stop command or the report command Note In most circumstances you should use a forever button in order to repeat something forever The advantage of using a forever button is that the user can click the button to stop the loop Iput Iput value list Adds value to the end of a list and reports the new list 7 suppose mylist is 2 7 10 Bob set mylist lput 42 mylist 5 mylist now is 2 7 10 Bob 42 map map reporter list map reporter list With a single list the given reporter is run for each item in the list and a list of the results is collected and reported In reporter use to refer to the current item of list show map round 1 1 2 2 2 7 gt 1
108. pictures below pH chemical concentration pressure etc TS The second mode of interaction between NetLogo and the physical world is the control of output devices or actuators motors light bulbs see pictures below LEDs and more complex devices that include these outputs such as toys remote controlled cars electrical appliances and automated laboratory equipment 262 NetLogoLab and the GoGo Board Extension NetLogo 4 1 2 User Manual For educators willing to start robotics or sensing projects there are some important considerations regarding the exact type of sensors and actuators to use for example the sturdiness reliability openness and cost of these devices Both vary greatly in price and complexity For example for most educational projects off the shelf generic low cost sensors can be used with very reliable results A generic temperature sensor with a precision of 0 5 degrees Celsius can be purchased for approximately US 1 00 at most sensor and electronics retailers Using generic low cost sensors requires very basic knowledge of electronics For example some basic soldering might be needed to attach a piece of wire to the sensors While this is feasible in schools and has been tried in several educational settings some educators might prefer to buy proprietary sensors and actuators which come assembled and ready to be used Some companies offer proprietary systems for educational s
109. raSter asa pcs aid 295 GIS SSSAMPIS ai de da DECIDE ada Da a tle 295 ASCO Bis gain red as RLL TE aaa pa bea eel LS rede eta ra 295 ASA AS A o as 296 Drawing PrimtVeS iia Editada DDS aco des Ega 296 o Se TALO 1010 0 PERA DER DS A SPO REPARE AA REDE O RE 296 QIS SEl GrAWING COlO his sinal asd Ai 297 NA 297 A impar RS AD aa N 297 AS PAM A TRT A da 297 QIS IMPOEWINS QTAWINQ cccccccccconcnononenenenenennnnnennnnnnnernnrr nn rre 297 AcknowledgmentsS eseeeeeeeeeenrtenernnrrenrrnnnrnnn taen rnen taent nenn nen nnen tae araen anen Eeen anen reen aeenreen reenen ee 298 FAQ Frequently Asked QuestiONS oooccocococcccccocncnnancccccccannnnnnnnnncrnnnnnnnnnnnnnnrrrrnnnnnnnannnnr nnmnnn 299 QUES Sn adi iio 299 AC A en 299 Downl0 adiciona made sand 299 Applets aria AA Ea 299 RUNNING e E e Seda Li ama 299 E E E EEE A E AE E AA ETE AE 300 PLOQKFAMIMING aaa aaa AA 300 BERAVIOI SPACE ius tia Did a 300 EXICASIONS He a E ED A AEN IAEA Me a DO da UA De E 301 A 301 Whits ni called Neto aiii i 301 How do cite NetLogo in an academic publicati0N cooomnocoocccnnnncccnonaconnnnnnnncnnanannns 301 How do cite a model from the Models Library in a publication 2 301 Where and when was NetLogo created ococcooooccocnccccccnononononncnncccnnnnonononcnnnnnnnnnnnnnnnnnnos 301 What programming language was NetLogo written in2 conos 301 What s the difference between StarLogo MacStarLogo StarLogoT and NetLogo 302 U
110. representations of the two objects have the given spatial relationship and false otherwise The spatial relationship is specified using a Dimensionally Extended Nine Intersection Model DE 9IM matrix The matrix consists of 9 elements each of which specifies the required relationship between the two objects interior space boundary space or exterior space The elements must have one of six possible values e T meaning the spaces must intersect in some way e F meaning the spaces must not intersect in any way e 0 meaning the dimension of the spaces intersection must be zero i e it must be a point or non empty set of points e 1 meaning the dimension of the spaces intersection must be one i e it must be a line or non empty set of line segments e 2 meaning the dimension of the spaces intersection must be two i e it must be a polygon or set of polygons whose area is greater than zero e meaning that the two spaces may have any relationship For example this matrix eer Boundary eee Boundary EC Exterior E E would return true if and only if some part of en X s interior lies inside object ys interior and no part of object x s interior or boundary intersects object ys exterior This is essentially a more restrictive form of the contains primitive one in which polygons are not considered to contain their boundaries 290 GIS Extension NetLogo 4 1 2 User Manual The matrix is given to th
111. reserved Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met e Redistributions of source code must retain the above copyright notice and include this license agreement e Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided with the distribution THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE 10 Copyright and License Information NetLogo 4 1 2 User Manual JAVA Advanced Imaging API Version 1 1 3 DISTRIBUTION BY DEVELOPERS Subject to the terms and conditions of the Software License Agreement and the obligations restrictions and e
112. result in extinction for one or more species involved In contrast a system is stable if it tends to maintain itself over time despite fluctuations in population sizes HOW IT WORKS There nre twan main varintinns n this mndel Interface Guide 87 NetLogo 4 1 2 User Manual You can edit the text in this view as in any text editor However a few different forms will be displayed specially when you switch out of the edit view Information Tab Markup Lines that come after blank lines and contain capital letters and no lower case letters AS WHAT IS IT become section headers Peer ale line that has only Peer ale is omitted Anything beginning with http becomes http ccl northwestern edu http ccl northwestern edu a clickable hyperlink E mail addresses become clickable bugs ccl northwestern edu bugs ccl northwestern edu mailto links Lines that begin with the pipe shift backslash become this is preformatted text this is preformatted text monospaced text This you can put spacesin it you can put spaces in it is useful for diagrams and formulas To return to the normal view click the edit button Procedures Tab This tab is the workspace where the code for the model is stored Commands you only want to use immediately go in the Command Center commands you want to save and use later over and over again are found in the Procedures tab 88 Interface Guide NetLogo 4 1 2 Us
113. running htto www javatester org Increasing the available memory Some NetLogo applets may require more memory than the browser normally makes available This may happen if you have large numbers of agents On Windows you can increase the available memory heap space in the Java Control Panel s applet runtime settings Mac OS X 10 4 users note that Mac OS X 10 4 initially had a rather low memory limit for Java applets namely 64 megabytes Eventually a Java update from Apple raised it to 96 megabytes You can get the update through Software Update If your browser is using the browser plug in that comes with the Sun JDK or JRE then instructions for starting the Java Plug In Control Panel are available here In the Advanced tab of the Control Panel add the following to the Java Runtime Parameters field Xmx1024M Features not supported in applets e Extensions that require native libraries won t work e The 3D view is not supported e The bytecode generator is not used in applets which means that some models run somewhat slower as applets e Web servers that return custom error messages may cause Java exceptions See the FAQ for the workaround 154 Applets Shapes Editor Guide The Turtle and Link Shape Editors allows you to create and save turtle and link designs NetLogo uses fully scalable and rotatable vector shapes which means you can create designs by combining basic geometric elements which can appear on screen in
114. specific prior written permission of the Authors THE SOFTWARE IS PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS NOR THEIR EMPLOYERS NOR GEORGE MASON UNIVERSITY BE LIABLE FOR ANY CLAIM DAMAGES OR OTHER LIABILITY WHETHER IN AN ACTION OF CONTRACT TORT OR OTHERWISE ARISING FROM OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE JpeglmagesToMovie For movie making NetLogo uses code adapted from JpeglmagesToMovie java by Sun Microsystems The copyright for that code is as follows 6 Copyright and License Information NetLogo 4 1 2 User Manual Copyright c 1999 2001 Sun Microsystems Inc All Rights Reserved Sun grants you Licensee a non exclusive royalty free license to use modify and redistribute this software in source and binary code form provided that i this copyright notice and license appear on all copies of the software and ii Licensee does not utilize the software in a manner which is disparaging to Sun This software is provided AS IS without a warranty of any kind ALL EXPRESS OR IMPLIED CONDITIONS REPRESENTATIONS AND WARRANTIES INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE OR NON INFRINGEMENT ARE HEREBY EXCLUDED SUN AND ITS LICENSORS SHALL NOT BE
115. sprout lt breeds gt subject turtles here Agentset turtles at turtles here turtles on Color approximate hsb approximate rgb base colors color extract hsb extract rgb hsb import pcolors import pcolors rgb pcolor rgb scale color shade of wrap color NetLogo Dictionary 317 NetLogo 4 1 2 User Manual Control flow and logic not or repeat report nessa Ai startup to to report wait E with local randomness without interruption xor World clear all ca clear drawing cd clear patches cp clear turtles ct display import drawing import pcolors import pcolors rgb no display max pxcor max pycor min pxcor min pycor patch size reset ticks resize world set patch size tick tick advance ticks world width world height Perspective follow follow me reset perspective rp ride ride me subject watch watch me HubNet hubnet broadcast hubnet broadcast clear output hubnet broadcast message hubnet broadcast view hubnet clear override hubnet clear overrides hubnet enter message hubnet exit message hubnet fetch message hubnet message hubnet message source hubnet message tag hubnet message waiting hubnet reset hubnet reset perspective hubnet send hubnet send clear output hubnet send follow hubnet send message hubnet send override hubnet send watch hubnet set client interface Input output beep clear output date and time export view export interface export output export plot export all plots export world import drawing import p
116. that the indices begin from 0 not 1 The first item is item 0 the second item is item 1 and so on set mylist 2 7 4 7 Bob set mylist remove item 2 mylist 7 mylist is now 2 7 7 Bob show remove item 2 string gt sting repeat repeat number commands Runs commands number times pd repeat 36 fd 1 rt 10 5 the turtle draws a circle 400 NetLogo Dictionary NetLogo 4 1 2 User Manual replace item replace item index list value replace item index string1 string2 On a list replaces an item in that list index is the index of the item to be replaced starting with 0 The 6th item in a list would have an index of 5 Note that replace item is used in conjunction with set to change a list Likewise for a string but the given character of string 1 removed and the contents of string2 spliced in instead show replace item 2 2 7 4 5 15 gt 2 7 15 5 show replace item 1 cat are gt caret report report value Immediately exits from the current to report procedure and reports value as the result of that procedure report and to report are always used in conjunction with each other See to report for a discussion of how to use them reset perspective rp reset perspective The observer stops watching following or riding any turtles or patches If it wasn t watching following or riding anybody nothing happens In the 3D view the observer also returns to its default position
117. the Command Center Tutorial 2 Commands 41 NetLogo 4 1 2 User Manual In Traffic Basic e Press the setup button e Locate the Command Center e Click the mouse in the white box at the bottom of the Command Center e Type the text shown here Command Center clear observer gt ask patches set pcolor yellow J v e Press the return key What happened to the View You may have noticed the background of the View has turned all yellow and the street has disappeared Why didn t the cars turn yellow too Looking back at the command that was written we asked only the patches to change their color In this model the cars are represented by a different kind of agent called turtles Therefore the cars did not received these instructions and thus did not change What happened in the Command Center You may have noticed that the command you just typed is now displayed in the white box in the middle of the Command Center as shown below Command Center WA Clear observer gt ask patches set pcolor yellow observer gt v e Type in the white box at the bottom of the Command Center the text shown below Command Center A Clear observer gt ask patches set pcolor yellow observer gt ask turtles E set color brown J Vv 42 Tutorial 2 Commands NetLogo 4 1 2 User Manual Was the result what you expected Your View should have a yellow background with a line of brown cars in th
118. the origin off center makes sense in your model at this time Before NetLogo 3 1 the world had to be symmetrical around the origin thus the world had to have an odd width and height This is no longer true since you may use any min and max combinations you wish given that the point 0 0 still exists in the world If you are logically only modeling in one or two quadrants or if it makes your code simpler to only use positive numbers you might want to consider changing your model If you ve modeled something that requires and even grid you ll certainly want to remove the programming hacks required to make that possible in the past 130 Programming Guide NetLogo 4 1 2 User Manual Code Examples Lattice Gas Automaton Binomial Rabbits Rugby For NetLogo 3 1 we added new primitives which are essential if you change the topology and quite convenient even if you don t random pxcor random pycor random xcor and random ycor report random values within the range between maximum and minimum x and y In older versions of NetLogo we often relied on wrapping to place turtles randomly across the world by writing set xy random float screen size x random float screen size y However if wrapping is not allowed in one direction or the other this no longer works you get a runtime error for trying to place turtles outside the world Regardless of topology it is simpler and more straight forward to use setxy random xcor random ycor instead To conv
119. the outcome the same as your previous run Just like buttons switches have information attached to them Their information is set up in an on off format Switches turn on off a separate set of directions These directions are usually not necessary for the model to run but might add another dimension to the model Turning the grass switch on affected the outcome of the model Prior to this run the growth of the grass stayed constant This is not a realistic look at the predator prey relationship so by setting and turning on a grass growth rate we were able to model all three factors sheep wolf and grass populations Another type of setting is called a slider Sliders are a different type of setting then a switch A switch has two values on or off A slider has a range of numeric values that can be adjusted For example the initial number sheep slider has a minimum value of O and a maximum value of 250 The model could run with O sheep or it could run with 250 sheep or anywhere in between Try this out and see what happens As you move the marker from the minimum to the maximum value the number on the right side of the slider changes this is the number the slider is currently set to Let s investigate Wolf Sheep Predation s sliders e Read the contents of the Information tab located above the toolbar to learn what each of this models sliders represents The Information tab offers guidance and insight into the model Withi
120. the room How many tiles away is the 0 0 tile from the right side of the room How many tiles away is the 0 0 tile from the left side of the room In NetLogo the number of tiles from right to left is called world width And the number of tiles from top to bottom is world height These numbers are defined by top bottom left and right boundaries 38 Tutorial 1 Models NetLogo 4 1 2 User Manual world width max pxcor max pycor world height 0 0 min pycor In these diagrams max pxcor is 3 min pxcor is 3 max pycor is 2 and min pycor is 2 When you change the patch size the number of patches tiles doesn t change the patches only get larger or smaller on the screen Let s look at the effect of changing the minimum and maximum coordinates in the world e Using the Settings dialog that is still open change max pxcor to 30 and max pycor value to 10 Notice that min pxcor and min pycor change too That s because by default the origin 0 0 is in the center of the world What happened to the shape of the view e Press the setup button Now you can see the new patches you have created e Edit the view by pressing the Settings button again e Change the patch size to 20 and press OK What happened to the size of the view Did its shape change Editing the view also lets you change other settings Feel free to experiment with these Tutorial 1 Models 39 NetLogo 4 1 2 User Manual O
121. tick advance reset ticks tick advance tick advance number w Advances the tick counter by number The input may be an integer or a floating point number Some models divide ticks more finely than by ones The input may not be negative See also tick ticks reset ticks ticks ticks Reports the current value of the tick counter The result is always a number and never negative Most models use the tick command to advance the tick counter in which case ticks will always report an integer If the tick advance command is used then ticks may report a floating point number See also tick tick advance reset ticks 416 NetLogo Dictionary NetLogo 4 1 2 User Manual tie tie Ties end and end2 of the link together If the link is a directed link end is the root turtle and end2 is the leaf turtle The movement of the root turtle affects the location and heading of the leaf turtle If the link is undirected the tie is reciprocal so both turtles can be considered root turtles and leaf turtles Movement or change in heading of either turtle affects the location and heading of the other turtle When the root turtle moves the leaf turtles moves the same distance in the same direction The heading of the leaf turtle is not affected This works with forward jump and setting the xcor or ycor of the root turtle When the root turtle turns right or left the leaf turtle is rotated around the root turtle the same amount The headi
122. to a three item RGB list with values in the 0 255 range and get that exact color See the Color section of the Programming Guide for details Tie In previous versions __tie was provided as an experimental feature As of NetLogo 4 0 links have a tie mode variable which can be set to none free or fixed In 4 0 tie is now a link only primitive This means that to tie turile 1 to turile O you write ask turtle O create link to turtle 1 tie See the Tie section of the programming guide for details HubNet Clients A HubNet activity s client interface is no longer stored in a separate model file To import a client from an old model select File gt Import gt Import HubNet Client Then when asked import from the Interface Tab You will no longer need the external client model and you will no longer need to point to it when setting the client interface so this hubnet set client interface COMPUTER my client nlogo becomes hubnet set client interface COMPUTER Transition Guide 149 NetLogo 4 1 2 User Manual Performance of Lists The internal implementation of lists has changed which changes some of the performance properties of lists see the Programming guide for details on the current implementation Note that fput is much faster than 1put thus you may improve performance simply by switching to put If performance is still a problem you may want to consider using the Array amp Table ex
123. to produce heading1 A positive answer means a clockwise rotation a negative answer counterclockwise The result is always in the range 180 to 180 but is never exactly 180 Note that simply subtracting the two headings using the minus operator wouldn t work Just subtracting corresponds to always rotating clockwise from heading2 to heading1 but sometimes the counterclockwise rotation is shorter For example the difference between 5 degrees and 355 degrees is 10 degrees not 350 degrees how subtract headings 80 60 gt 20 how subtract headings 60 80 gt 20 how subtract headings 5 355 gt 10 how subtract headings 355 5 gt 10 how subtract headings 180 0 gt 180 how subtract headings 0 180 gt 180 o lo po tila i wv i a sum sum list Reports the sum of the items in the list show sum energy of turtles 7 prints the total of the variable energy from all the turtles NetLogo Dictionary 415 NetLogo 4 1 2 User Manual T tan tan number Reports the tangent of the given angle Assumes the angle is given in degrees thickness thickness This is a built in link variable It holds a number that is the link s apparent size as a fraction of the patch size The default thickness is 0 which means that regardless of patch size the links will always appear 1 pixel wide You can set this variable to change a link s thickness tick tick 5 Advances the tick counter by one See also ticks
124. turtles vision e Can agents sense what s in the drawing layer e I m getting numbers like 0 10000000004 and 0 799999999999 instead of 0 1 and 0 8 Why e The documentation says that random float 1 0 might return 0 0 but will never return 1 0 What if want 1 0 to be included e How can use different patch neighborhoods circular Von Neumann Moore etc e How can keep two turtles from occupying the same patch e How can find out if a turtle is dead e Does NetLogo have arrays e Does NetLogo have hash tables or associative arrays e How can convert an agentset to a list or vice versa e How do stop foreach BehaviorSpace e Why are the rows in my BehaviorSpace table results out of order e How do gather data every n ticks 300 FAQ Frequently Asked Questions NetLogo 4 1 2 User Manual e I m varying a global variable declared in the Procedures tab but it doesn t work Why e Why are some of my results cut off in Excel Extensions e I m writing an extension Why does the compiler say it can t find org nlogo api General Why is it called NetLogo The Logo part is because NetLogo is a dialect of the Logo language Net is meant to evoke the decentralized interconnected nature of the phenomena you can model with NetLogo including network phenomena It also refers to HubNet the multiuser participatory simulation environment included in NetLogo How do cite NetLogo in an academic publication
125. unless you really want it If you do want spreadsheet output note that if anything interrupts the experiment such as a runtime error running out of memory or a crash or power outage no spreadsheet results will be written For long experiments you may want to also enable table format as a precaution so that if something happens and you get no spreadsheet output you ll at least get partial table output After selecting your output formats BehaviorSpace will prompt you for the name of a file to save the results to The default name ends in csv You can change it to any name you want but don t leave off the csv part that indicates the file is a Comma Separated Values CSV file This is a plain text data format that is readable by any text editor as well as by most popular spreadsheet and database programs Run options parallel runs The run options dialog also lets you select whether you want multiple model runs to happen in parallel and if so how many are allowed to be simultaneously active This number will default to the number of processor cores in your computer There are a few cautions associated with parallel runs First if multiple runs are active only one of them will be in the foreground and cause the view and plots to update The other runs will happen invisibly in the background Second invisible background runs can t use primitives that only work in the GUI For example a background run can t make a movie Thi
126. values of all variables both built in and user defined including all observer turtle and patch variables the drawing the contents of the output area if one exists the contents of any plots and the state of the random number generator to an external file given by the string filename The result file can be read back into NetLogo with the import world primitive export world does not save the state of open files NetLogo Dictionary 341 NetLogo 4 1 2 User Manual export plot export all plots and export world save files in in plain text comma separated values csv format CSV files can be read by most popular spreadsheet and database programs as well as any text editor If you wish to export to a file in a location other than the model s location you should include the full path to the file you wish to export Use the forward slash as the folder separator Note that the functionality of these primitives is also available directly from NetLogo s File menu export world fire csv 7 exports the state of the model to the file fire csv 7 located in the NetLogo folder export plot Temperature c My Documents plot csv 7 exports the plot named Temperature to the file plot csv located in the C My Documents folder export all plots c My Documents plots csv 77 exports all plots to the file plots csv located in the C My Documents folder If the file already exists it is overwritten To avoid this
127. visible again Note This command is equivalent to setting the link variable hidden to false See also hide link shuffle shuffle list Reports a new list containing the same items as the input list but in randomized order show shuffle gt 52 4 1 3 show shuffle gt 1352 4 12345 1 2 3 4 5 sin sin number Reports the sine of the given angle Assumes angle is given in degrees show sin 270 gt 1 size size x This is a built in turtle variable It holds a number that is the turtle s apparent size The default size is 1 which means that the turtle is the same size as a patch You can set this variable to change a turtle s size sort sort list sort agentset Reports a sorted list of numbers strings or agents NetLogo Dictionary 411 NetLogo 4 1 2 User Manual If the input contains no numbers strings or agents the result is the empty list If the input contains at least one number the numbers in the list are sorted in ascending order and a new list reported non numbers are ignored Or if the input contains at least one string the strings in the list are sorted in ascending order and a new list reported non strings are ignored Or if the input is an agentset or a list containing at least one agent a sorted list of agents never an agentset is reported non agents are ignored Agents are sorted in the same order the lt operator uses show sort 3 1 4 2 gt 1 2 3 4 let n
128. word tur tle gt turtle word a 6 gt a6 set directory c foo fish show word directory bar txt gt c foo fish bar txt show word 1 54 8 fishy gt 1 54 8 fishy show word 3 gt 3 show word a pb e 1 23 gt abcl23 world width world height world width world height These reporters give the total width and height of the NetLogo world The width equals max pxcor min pxcor 1 and the height equals max pycor min pycor 1 See also max pxcor max pycor min pxcor and min pycor wrap color wrap color number wrap color checks whether number is in the NetLogo color range of 0 to 140 not including 140 itself If it is not wrap color wraps the numeric input to the 0 to 140 range The wrapping is done by repeatedly adding or subtracting 140 from the given number until it is in the 0 to 140 range This is the same wrapping that is done automatically if you assign an out of range number to the color turtle variable or pcolor patch variable show wrap color 150 gt 10 show wrap color 10 gt 130 NetLogo Dictionary 429 NetLogo 4 1 2 User Manual write write value This command will output value which can be a number string list boolean or nobody to the Command Center not followed by a carriage return unlike print and show This agent is not printed before the value unlike show lts output also includes quotes around strings and is prepended with a spa
129. xcor let new y new value of ycor ifelse patch at new x xcor new y ycor nobody hide turtle setxy new x new y show turtle Several models in the Models Library use this technique Gravitation N Bodies and Electrostatics are good examples By using a different topology you get diffuse for free which was fairly difficult to do in the past Each patch diffuses and equal amount of the diffuse variable to each of its neighbors if it has fewer than 8 neighbors or 4 if you are using diffuse4 the remainder stays on the diffusing patch This means that the overall sum of patch variable across the world remains constant If you had special code to handle diffuse then you can remove it However if you want the diffuse matter to still fall off the edges of the world as it would on an infinite plane you still need to clear the edges each step as in the Diffuse Off Edges Example Links A link is an agent that connects two turtles The two turtles are called nodes The link is always drawn as a line between the two turtles Links do not have a location as turtles do they are not considered to be on any patch and you cannot find the distance from a link to another point There are two flavors of links undirected and directed A directed link is out of or from one node and into or to another node The relationship of a parent to a child could be modeled as a directed link An undirected link appears the same to both nodes
130. 1 NetLogoLab and the GoGo Board Extension 267 NetLogo 4 1 2 User Manual x Reporter gogo sensor 1 Display name Sensor 1 Decimal places O Font Size 11 full precision is 17 The sensor values shown are arbitrary numbers within a given range and need to be properly converted to actual temperature units such as degrees Celsius or Fahrenheit For all sensors the GoGo Board s reporting range is from 0 to 1023 Every sensor comes with a data sheet with a converting formula or table that will transform the arbitrary 0 1023 range into an actual physical unit Let us imagine that the sensor s data sheet contains a conversion formula that looks like this degrees arbitrary value 30 The monitor on the NetLogo interface could be changed to gogo sensor 1 30 The sensor value could also be used to control on screen objects such as turtles For example let us create two buttons a create one turtle button which will clear the world and create a turtle and a move with heat button that will cause the turtle to move forwards depending on the temperature reading from the sensor The code would look like this to create one turtl clear all create turtle end to move with heat if gogo sensor 1 lt 500 forward 1 end If the move with heat forever button is activated and the user heats up the sensor by rubbing it or slowly bringing a flame near it the heat threshold will be achieved lt
131. 1 2 User Manual histogram age of turtles The numbers you want to histogram don t have to come from an agentset they could be any list of numbers Note that using the histogram command doesn t automatically switch the current plot pen to bar mode If you want bars you have to set the plot pen to bar mode yourself As we said before you can change a pen s default mode by editing the plot in the Interface tab The width of the bars in a histogram is controlled by the plot pen s interval You can set a plot pen s default interval by editing the plot in the Interface tab You can also change the interval temporarily with the set plot pen interval command or the set histogram num bars If you use the latter command NetLogo will set the interval appropriately so as to fit the specified number of bars within the plot s current x range Code Example Histogram Example Clearing and resetting You can clear the current plot with the clear plot command or clear every plot in your model with clear all plots The clear a11 command also clears all plots in addition to clearing everything else in your model If you only want to remove only the points that the current plot pen has drawn use plot pen reset When a whole plot is cleared or when a pen is reset that doesn t just remove the data that has been plotted It also restores the plot or pen to its default settings as they were specified in the Interface tab when the plot was create
132. 1 2 User Manual plot plot number Increments the x value of the plot pen by plot pen interval then plots a point at the updated x value and a y value of number The first time the command is used on a plot the point plotted has an x value of 0 plot name plot name Reports the name of the current plot a string plot pen exists plot pen exists string Reports true if a plot pen with the given name is defined in the current plot Otherwise reports false plot pen down plot pen up plot pen down plot pen up Puts down or up the current plot pen so that it draws or doesn t By default all pens are down initially plot pen reset plot pen reset Clears everything the current plot pen has drawn moves it to 0 0 and puts it down If the pen is a permanent pen the color and mode are reset to the default values from the plot Edit dialog plotxy plotxy number number2 Moves the current plot pen to the point with coordinates number1 number2 If the pen is down a line bar or point will be drawn depending on the pen s mode NetLogo Dictionary 393 NetLogo 4 1 2 User Manual plot x min plot x max plot y min plot y max plot x min plot x max plot y min plot y max Reports the minimum or maximum value on the x or y axis of the current plot These values can be set with the commands set plot x range and set plot y range Their default values are set from the plot Edit dialog position position i
133. 2 3 show map 2 1 2 3 gt 1 4 9 With multiple lists the given reporter is run for each group of items from each list So it is run once for the first items once for the second items and so on All the lists must be the same length In reporter use 1 through 2n to refer to the current item of each list Some examples make this clearer show map 21 2 1 2 3 2 4 6 gt 3 6 9 show map 1 2 3 1 2 3 2 4 6 3 5 9 gt true false true 372 NetLogo Dictionary NetLogo 4 1 2 User Manual See also foreach max max list Reports the maximum number value in the list It ignores other types of items show max xcor of turtles 7 prints the x coordinate of the turtle which is 5 farthest right in the world max n of max n of number agentset reporter Reports an agentset containing number agents from agentset with the highest values of reporter The agentset is built by finding all the agents with the highest value of reporter if there are not number agents with that value then agents with the second highest value are found and so on At the end if there is a tie that would make the resulting agentset too large the tie is broken randomly 7 assume the world is 11 x 11 show max n of 5 patches pxcor 7 shows 5 patches with pxcor max pxcor show max n of 5 patches with pycor 0 pxcor 7 shows an agentset containing 7 patch 1 0 patch 2 0 patch 3 0 pa
134. 2 User Manual Note that the turtle always ends up on a patch center and has a heading that is a multiple of 45 downhill or 90 downhill4 See also uphill uphill4 dx dy dx dy Reports the x increment or y increment the amount by which the turtle s xcor or ycor would change if the turtle were to take one step forward in its current heading Note dx is simply the sine of the turtle s heading and dy is simply the cosine If this is the reverse of what you expected it s because in NetLogo a heading of O is north and 90 is east which is the reverse of how angles are usually defined in geometry Note In earlier versions of NetLogo these primitives were used in many situations where the new patch ahead primitive is now more appropriate E empty empty list empty string Reports true if the given list or string is empty false otherwise Note the empty list is written The empty string is written end end Used to conclude a procedure See to and to report end1 end1 This is a built in link variable It indicates the first endpoint turtle of a link For directed links this will always be the source for undirected links it will always be the turtle with the lower who number You NetLogo Dictionary 339 NetLogo 4 1 2 User Manual cannot set end1 Cre 2 ask turtle 0 create link to turtle 1 ask links show endl shows turtle 0 end2 end2 amp This is a built in link va
135. 315 EXTENSIONS ad o E e N Pa uid a NE AS E DI ad 315 I m writing an extension Why does the compiler say it can t find org nlogo api 316 NetLogo DICHON Vii DA ES 317 CASINOS a as 317 Turte related ss us ad OT PALCO do 317 Patch aducir A A Mie a ia 317 A E 317 COEL a EN a A DR da A NA BN A O A JURA TO oe 317 Control flow and OC ia da is da 318 A NS 318 Perspective RR rare RR ada capas 318 HUbNet ts a a a e alga de a Bee cd eel 318 INDUVOU PU inicia a a a 318 A O 318 A A A OO 318 e EE Sc a asia ng ae eae E A O oes cate haa di 319 RENE AEE den e dea e 319 PIO AA AAN Arda 319 Kari da it als tities a Mech o a co eds Din da iai Lio Sal 319 MOV a e o de e ad 319 XV NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary BENAVIOLS PACO nai ba 319 A O O 319 Built In Varlables ococoocccononincncncnocncnnanononcnnnnnnononnnnn nano nan nono nnnnn nano area arena nara anne nana 320 A ERR E RR RREO a gk T eS tee RR ERR RR 320 Patches tant is id iaa 320 A A A Det sa O DE oa SE a Ud 320 OTher pras mor nt cd Edo EE ne Bem Rte eae se att ee toe ee ped gt em Sie sects ba 320 KO WOldS ii ii 320 ConstantS a A SE E A A a a tia 320 Mathematical GonstantS iii tac 320 Boolean GSM E 320 COMIDO ad NS Ss 320 ANTAS AAA A E AN tas ey a AS IR Aa a 321 E S Date Ser aa eu Doni Dito Tg Nt e ah ole cri Set hea A a aa 321 A EE AEA ES a E O SR E Areata ahanseeunt es 321 malta nea 321 GUNG 2 ORNE IA AR RDNS AS BRAD
136. 355 hubnet MESSage WaltidQ cccooooccccnnnccccnnnnononnnncncnnnnnnononnnnnnnnnnnnnnnnnnnnnnnnrrnrnnnnnnenennnnnnnn 355 UBICA ee DESEO 355 hubnetteset perspectiVe ooocooccconoconoconocononnnonn co nnnonnnnnnn nino nono nnnnnnnn o nero nnnn nn nn nn nn nn nn nnnnnnnnnnos 356 NUNES dr la iodo 356 hubnet send clear QUtDUtcoooococccccoccoonooonononnnn nono nonononnnnnnnnnonnnnnnnnnnnnnnonnnnnnnnnnnnnnnnnnnnnnnnnnos 356 hubert send OOW a a nana nn nono nannno nana na A 356 AA 357 h bnetsend override ii A at 357 hUDNE ISeNO WatCh oooccccnccccnoccconccnnnccnonanoconcccnnncnnoncnnonannnnnnnnoncnnonn nano ncnnonccnn nana nanannananas 357 hubnet set client interface errar ereta erra ono nana na a 357 EE PE E E A A A A a E 358 BI A ERES AE OE AE E AO 358 EE sara E RENEA AEN ds E a EEEE A E ADE ot EEEE TIE 358 NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary CER AO 358 IMPOCEA WIN Oido das Riad a dara red 359 IMMDOF ECONO ee 359 IMportpcolOrS TOD iniciarse aa aa a aa eaa aa a eeh Saai aaier a aeaa 360 IMPOF WOMG strass done ae a aie a aa e era e e a R 360 MECO A AE OA Sa Ghat Mah ace AEA 360 in lt breed gt neighbor in link NneighbOrB ooooooccccnnnnonnononccncnnnncononnnnnonnnnnnoncnnnanononcnnnnnnnns 361 in lt breed gt neighbors in lidk NeighDOTFS ooooooccocncocncooccnonocononononononnnnonnnonnnnnnnnnnnnnnnnnnnnnnos 361 in lt breed gt from TO el 11 01 110 80 nana nono nana nnnn nono ncnn nana ncno nana n
137. 360 forward 1 setlenergyienezgy 1 As each turtle wanders it will lose one unit of energy at each step e Switch to the Interface tab now and press the setup button and the go button You ll see the patches turn black as turtles travel over them 58 Tutorial 3 Procedures NetLogo 4 1 2 User Manual Monitors Next you will create two monitors in the Interface tab with the Toolbar You make them just like buttons and sliders using the monitor icon on the Toolbar Let s make the first monitor now e Create a monitor using the monitor icon on the Toolbar and click on an open spot in the Interface A dialog box will appear e In the dialog box type count turtles see image below e Press the OK button to close the dialog box Tutorial 3 Procedures 59 NetLogo 4 1 2 User Manual Monitor Display name Decimal places 3 FontSize 11 full precision is 17 Cancel Cok 4 ZA turtles is an agentset the set of all turtles count tells us how many agents are in that set Let s make the second monitor now e Create a monitor using the monitor icon on the Toolbar and click on an open spot in the Interface A dialog box will appear e Inthe Reporter section of the dialog box type count patches with pcolor green see image below e In the Display name section of the dialog box type green patches e Press the OK button to close the dialog box 60 Tutorial 43
138. 38 Coments A ao dc Mae tne eal RC aan Sa DRC eat Meee a E 138 SUCIO er E E cata ek E DO Biel de O ae ees ANDES ice a Cc det UI A aah a 138 GOMMANGS ANG Reporters ssa ua iai inda aii 139 Compared to other LOGOS saias Santas sd ada 139 Transition Quide ssa solo datos dis ant aiii A Ai A 141 once NetLodo 4 0 geidsretivncscocuetecattasancheansta R da DECR aa ra Dead a 141 Combining SOLA Oda 141 ADDICIS acia A e A da 142 NetLogo 4 1 2 User Manual Table of Contents Transition Guide WHO M MIA a ios 142 Turtle creation randomized vs OlderO O dennccconncccncccnnonononcnonannnnna nano nono nan no non nnn narra nannannn 142 Adding strings and Ml tse 143 The at primiliv S ces rain a ida 143 EOS a NN A Hd Sita dion A AS 143 PW OTS A A A 145 SA e a O os ide 145 TICS COLMO o CM at Mis 146 VIEW update ModS iia dat 146 Speed lO A o GR IR ROO CR RR DSR RR AE UR ERR 147 Numbers ua dao Coe dA e nad e da Dando Ne do Bate o A O 148 Agentset buUldINA siii aida 149 RGBiGOlOrs it Rite A laz 149 A O NN 149 HUDN EE Glenia ici d 149 Performance Or List tii da 150 Since Nation iS 150 AgentselS meiga te rage e RRA REA AER eds ra adia mad 150 WV RADON ei A E PAG Coan da A SRU AR DEN E RSRS ANE AE MAR Ena oa 150 Random turtle COOrdiNMatles occccoccccnoccccncnnonaniconcnnnnancnnnnnnonannonannnn narran nana n narran nara nana 150 Applets O 153 Making an applet e ereeare rara aara nara aaa anna anna a naa anna cana nana cana na
139. 40 AUTO dius a RR eet Ae 240 UTA a at Ad dd RA Ri a SRU dO Ud a 241 A SN 241 Table Primitives aaran raa taza 241 Ali a ida 241 table tromliS 2334 Ds e E AS 241 tabla ad 241 a A aaa 241 Table KEYS iii A CRT US A ER Et 241 tc le SH O ROTO 242 tabe maka sus Custas seita fo as Sra nie ales Aa ed ad RN ds Ds 242 table pulsa iss esa a EDDIE dd DADO Da ste 242 El 242 table ORNS beset 02 att as da A e eee os AG AI da do a tn ER A 242 Matrix EXtenSlON iia daa aii 243 When OEE aa cece o e de a da a ERR N 243 IOWA AI ELE A E EAE iodo nia cod 243 Matrix example ei ee E na salario 243 Matrix Primite Seana a A E N 244 Matrix creation 8 conversion to from lists 244 Matrix data retrieval and manipulatiOM oooooconcnnnnonnnooncoonocononononononnnnnnnnnnnnnnnnnnnnnnnnonnnnnnos 244 Math Operations ee aaa eae aeaa aaa a a a a aaa ahe iaaiaee sees 244 Advanced teatre ni E A E E E AE lana AA 244 Matrix creation amp conversion to from lists eee nan cnn nana ncn cnn 244 matrix MAake CONStaNL cccoocccnnncccnnccconccnnnacononccnnnncononcnno nara nnn cano arara nano rara anna arena arara 244 matrix make identity iii nne ea ae r nro n nn nn nn aa a nia 244 matrix from row list a a oaa a E a a a aaaea eda 245 MaX FOM COUM H S di a ated ali 245 MAEA OLON EE E E EE A A A A E A ET OAO 245 matrix t0 C0 UM E PETI A EIE A E A a tern aieewaies 245 MATIC Las E E E A E E E E A aaa 245 matrix pretty printtext siii a oa tied La e
140. 7 128 Telephone Ring Helicopter Applause Gunshot Sound Extension NetLogoLab and the GoGo Board Extension What is NetLogoLab NetLogoLab is the technological infrastructure that connects NetLogo and the physical world It can be used for robotics interactive art scientific investigations and model validation For more information please check the NetLogoLab web site where you will find academic papers and demos NetLogoLab is comprised of the following software and hardware components 1 A NetLogo extension to control a robotics or data logging board 2 A robotics or data logging board also know as a serial interface board or analog to digital board 3 Sensor and actuator toolkits 4 NetLogo models NetLogo s robotics data logging board of choice is the GoGo Board an open source easy to build low cost interface originally designed at the MIT Media Lab by Arnan Sipitakiat Other robotics hardware can be used with NetLogo including those that are commercially available such as Vernier and Pasco sensors and actuators Phidgets Lego robotics kits and VEX kits but specific extensions still need to be developed for each of those platforms So far only the GoGo Board extension is available with NetLogo s standard distribution The GoGo Board NetLogo extension The GoGo Board extension is a software component that enables the user to connect NetLogo with the physical world using sensors motors light bulbs LEDs
141. 999 instead of 0 1 and 0 8 Why See the Math section of the Programming Guide in the User Manual for a discussion of this issue The documentation says that random float 1 might return O but will never return 1 What if want 1 to be included It really doesn t matter Even if 1 were a possible result it would only come up approximately 1 in 2164 tries which means you d be waiting hundreds of years before it ever came up exactly 1 Nonetheless if you are convinced that it really must be possible to get 1 you can use precision to round your answer to a certain number of decimal places For example print precision random float 1 10 0 2745173723 If you use this method note that O and 1 are only half as likely to come up as other answers To see why this is so consider the case where you only keep one digit after the decimal point Results between 0 and 0 5 get rounded to 0 but results between 0 5 and 1 5 get rounded to 1 the latter range is twice as large If you want 0 0 1 0 2 0 9 and 1 to all be equally likely an alternative is to write random 11 10 this gives all 11 answers with equal probability How can I keep two turtles from occupying the same patch See One Turtle Per Patch Example in the Code Examples section of the Models Library How can find out if a turtle is dead When a turtle dies it turns into nobody nobody is a special value used in NetLogo used to indicate the absence of a turtle or p
142. A O EE GEO STAROS DEDO GALO Dois LO E E USD dal a o 349 IN sa pri so PPP EDE EE AE E ae Dea A Dea aos Dae wea E EE dos dada coves 349 OIREET a sn mass again tata na PE rasca dot dedo qa need ud EEE TA a a eae 349 NS oh Nado Ro EE gE DA Oe a a A NC Ne da a TE hoe 350 UA o 350 O A A ta A e 350 A NO 350 A E AA 350 Nach Naicn lt DTCE ASS 351 NC ii va 351 A a STA UA CEA EE TE Mate Dr SR ceed tad suabdataes 351 nideslink nas co sacra ra a poa dp e o AS DG pd TSG LO RO RE CE RU do a A E 352 hide t rile Mita a ai Ia nba NE SA a Dede Dales Sola da des abate davene 352 ASOMAN Aid 352 A O O 353 A A EE E A OSO 353 NUDE EDO ACA dt 353 hubnet broadcast clear QUtDUb coooocccccccococonaoonocononononnnonnno nono nononononnnnonnnnnnnnnnnnnnnonnnnnnnnnnos 353 hubnet broadcast MessaQe ooococcccccoooooonooonnnononononononnnnnnno nono nono no non nnnnnnnnnnnnnnnnnnnnnnnonnnnnnos 353 hubnet bDrOadCast VIeW ooccccnoccccnccccnccnnnonononcccnnncnnoncnnoncnnnnnnononcnno nana noncnno EEn nana ca arara 354 hubnet clear override hubnet clear Overrides ooccccoccccnoccccncccnnaciconccnnnccnnnanaconccnanonas 354 Hubnet antor nessa a 354 MUDNOT SOX IO A A UE ia 354 hubnet fetch MESSAE ccescessncececeeeesseeenneeeeeeeeseecseceeeeeeeeeeeeesscnaaeeeeeeeessesseseeeeeeeeees 354 NUDE E Mess alii dic 355 NUbNet MESSAGE SOUICE cococcoocccoconononnno nono nono non nn nnnnnnnnnn non nnnnnnnnnnnn nn nn nn nn nn nn nnnnnnnnnnnnnnnnnnos 355 hUDNetMEessagetad ee
143. CO linia ai 373 nalete AT O A A E RR A A A AE 374 RN NR 374 Member ia tn 374 A ES A Mateos cleo ee ct A etal eee Gas Ra E Men SD A AE 375 PTS Obes nas TR 375 MINOS Odin E E EE 375 MIN PXCOMIN OV Clin e a a ara a a ra da a enit 376 MOO TR 376 ANELEE e EEE A EEA dt A A ad RR dada ee 376 MAUI A MR NR OR UR ERROR E AR ik RR RI RR 377 MOUSO ANSIA ia VEL SAL DAS A E ad 377 mouse xcor MOUSO YC Ol eireta none ea aa aaa A Te EENAA VASEA 377 MOVe O tda EE AE EEEE e de a A A A ud E EEE 377 Movie Caneel anir REE TEE A A OEA T A 378 MOVIE CIOSE iia A eda weed de ete dv E EE SE 378 movie grab view movie grab Interface oooooooccccnncccnnonononncccnnnnnccnnnanononnnnccnnnnnanononennnnnnnns 378 movie set irame fale E A EA EA 378 MOVIES EEA TE PE A ai TIAE A TE T 379 MOVIE SIALUS ira ri AA TN AA AR etn ceed 379 MY lt DFESUSS MY NAKS iii dd aida 379 my in lt breedsS gt MY iN liINKS iii eee eeeeeeaeeeeeeeeaeaeseaeseeeaeaeaeenseeneeese 379 my out lt breeds gt MYy OUT lINKS eee cece eeeceeeeeeeeeeeeee eee nono no nono nonnnnonnnnnnnonnnnnnnnnnnonnnnnnos 380 O E A aaa 380 pao ie A a e ano 381 Fe SS PARE o RE ND REAR e ao PESC A ds BRE RA SORTE NENE lo DA CARNE NR 381 NEVES nes ee bas sina col boca nono Ani a od a 381 Neighbors nelgnborsa iii ica 382 lt breed gt neighbors link neighbors seara eeaaeesaeeaaeeraee 382 lt breed gt neighbor link Neighbor occcocnnconccocnnonccononanonnnnnnncccnnnanonnnnnnncnnnnnannnonenc
144. D NetLogo 4 1 2 User Manual world height world depth It s important to keep this in mind when you are building your model Lots of patches can slow your model down or even cause NetLogo to run out of memory e Type ask patch 1 2 3 set pcolor red into the Command Center e Use the mouse in the 3D view to rotate the world Notice the shape of the patch and its position in relation to the edges of the world You ll also notice that you now need three coordinates to address patches in a 3D world Step 2 Turtle Movement e Open the Models Library in the File Menu if you are on a Mac and you don t have a File Menu click on the NetLogo window and it should reappear e Open Turtle and Observer Motion Example 3D in 3D Code Examples Take a moment to look for the controls and monitors In the bottom left you ll notice a group of monitors that describe the location and orientation of the turtle though until you press the SETUP button they ll all say N A e Press the setup button Heading pitch and roll are turtle variables that describe the orientation of the turtle Heading is absolute in relation to the xy plane it is the rotation of the turtle around the z axis Pitch is the angle between the nose of the turtle and the xy plane it is relative to heading Introducing NetLogo 3D 213 NetLogo 4 1 2 User Manual xy plane Roll is the rotation around the turtle s forward vector it is relative to heading an
145. EE A E E ET E AE A EEE dd 258 NetLogo 4 1 2 User Manual Table of Contents NetLogoLab and the GoGo Board ExtenSiON ooommooonccccccconnnnnanncnccnonnnnnnnnnnnnnonnnnnnnnnnnnnnrrrrrrnrnnanas 261 Whatis NGtEO GOA Avs suit ara aia 261 The GoGo Board NetLogo Extension ccccsssscecceeecssseeeeeeeeeeceesessesneseeeeeeeeeesessnaaees 261 GoGo Board a low cost robotics and data logging board renee 261 Sensor and actuator toolkits tecer carreata erre eterna atas 261 Netlogo modelS atas teses dira 263 HOW 16 gera GoGo Board Z paisana feno ii A A AN 263 Installing and testing the GOGO EXtenNSiON ooooccccccccnnonononccnnnnonnnnnnnnnnnnnnnnnnnnnnnnononnnnnccnnnnannns 264 ANVINdOWS a CA ata E O nad 264 MAG OS A A Da Ta Eau A 264 LINDO ci retas en hs erst aa Sad Lana suet a ca a a a aa el era 264 Using the GOGO EXTERIOR E ie RA a a 265 Examples of NetLogol ab MOR Saca 265 Control atari OA SD Fa a ran ee 265 A simple SENSING project rear eeareeee rasa rasa rasa rre 267 ETIMIIVES 0 R solos o e D AE Beech o a did ato Dos odad pai code a Rea sia aS 269 gogo DurStEVa LS nie ie ceras pve la Ie lo 269 JOJOICIOSO mos teste aeiiir seas dedo Ta DECR di ed DADO Da a site 269 o ojo o Ho 6 mira old 269 A TOS 270 JOJO POS aia epi 270 d0JO OUIpUL DPOFCOASt cias ala 270 JOJO OUT OUT DOM ON PR SED EL E a 270 o o fo o Ho JU LI o O 210 gogo ouipui pori reverse serra ee
146. Floor Tom 67 Hi Agogo 44 Pedal Hi Hat 68 Low Agogo 45 Low Tom 69 Cabasa 47 Open Hi Hat 70 Maracas 47 Low Mid Tom 71 Short Whistle 48 Hi Mid Tom 72 Long Whistle 49 Crash Cymbal 1 73 Short Guiro 50 Hi Tom 74 Long Guiro 51 Ride Cymbal 1 75 Claves 52 Chinese Cymbal 76 Hi Wood Block 53 Ride Bell 77 Low Wood Block 54 Tambourine 78 Mute Cuica 55 Splash Cymbal 79 Open Cuica 56 Cowbell 80 Mute Triangle 57 Crash Cymbal 2 81 Open Triangle 58 Vibraslap Instruments Piano Reed 1 Acoustic Grand Piano 65 Soprano Sax 2 Bright Acoustic Piano 66 Alto Sax 3 Electric Grand Piano 67 Tenor Sax 4 Honky tonk Piano 68 Baritone Sax 5 Electric Piano 1 69 Oboe 6 Electric Piano 2 70 English Horn 7 Harpsichord 71 Bassoon 8 Clavi 72 Clarinet Chromatic Percussion Pipe 9 Celesta 13 PLECOLO 10 Glockenspiel 74 Flute 258 Sound Extension 11 Music Box 12 Vibraphone 13 Marimba 14 Xylophone 15 Tubular Bells 16 Dulcimer Organ 17 Drawbar Organ 18 Percussive Organ 19 Rock Organ 20 Church Organ 21 Reed Organ 22 Accordion 23 Harmonica 24 Tango Accordion Guitar 25 Nylon String Guitar 26 Steel Acoustic Guitar 27 Jazz Electric Guitar 28 Clean Electric Guitar 29 Muted Electric Guitar 30 Overdriven Guitar 31 Distortion Guitar 32 Guitar harmonics Bass 33 Acoustic Bass 34 Fingered Electric Bass 35 Picked Electric Bass 36 Fr
147. Go extension now supports burst mode e language changes 4 set variable of is no longer allowed use ask set variable instead the with min and with max primitives now have the same precedence as with e user interface changes new menu item on Tools menu closes all agent monitors new NetLogo Users Group item on Help menu the snap to grid setting in the Interface tab is now saved with the model turning off turtle and link shapes is no longer supported the 3D and 2D views may now both be active at the same time for 2D models improved fonts on Windows improved look and feel on Linux e bug fixes asingle web page may now contain multiple NetLogo applets the includes keyword now works in applets the profiler extension is now much faster 4 fixed system dynamics modeler bug where incorrectly parenthesized code was generated for some expressions 4 fixed system dynamics modeler bug where some models did not work correctly when run in headless mode the array and table extensions are now fully compatible with exporting and importing worlds some link primitives are now faster on dense networks fixed bug where using the precision primitive with negative precisions could give non integer results improved error detection on extremely large integers fixed bug in forward primitive in non toroidal worlds fixed bug where link agentsets sometimes behaved incorrectly when links died fixed bug in world importing wh
148. Licensee a non exclusive royalty free license to use modify and redistribute this software in source and binary code form provided that i this copyright notice and license appear on all copies of the software and ii Licensee does not utilize the software in a manner which is disparaging to Sun This software is provided AS IS without a warranty of any kind ALL EXPRESS OR IMPLIED CONDITIONS REPRESENTATIONS AND WARRANTIES INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE OR NON INFRINGEMENT ARE HEREBY EXCLUDED SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING MODIFYING OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE PROFIT OR DATA OR FOR DIRECT INDIRECT SPECIAL CONSEQUENTIAL INCIDENTAL OR PUNITIVE DAMAGES HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY ARISING OUT OF THE USE OF OR INABILITY TO USE SOFTWARE EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES This software is not designed or intended for use in on line control of aircraft air traffic aircraft navigation or aircraft communications or in the design construction operation or maintenance of any nuclear facility Licensee represents and warrants that it will not use or redistribute the Software for such purposes ASM For Java bytecode generation NetLogo uses the ASM library It is di
149. N MOGES smana e AA AA E aa Sana ees 392 NO 392 ole LEEA O andes O E A 392 plabDel Cola A RE AEE E E OE 392 Pl ias 393 DIOL NAM EA A ee AA aii usas 393 DIO DENEBHISIS O A A dd 393 plot pen down plot pen up rre rr 393 DOE TE itv A A AA A a ds 393 A POR RE DARREN RE RAS RR RR RR ERR ER RU ES 393 plot x min plot x max plot y min plot y max see 394 POSI Mies A Sina ala id Da Saida do 394 DES Mii A A UNS Ed An ERA A dar da 394 JOTI MARAR RR a ORNE A EP TUR 395 PX COM 0AL0 TIERA PE E At 395 U a E E AE E TE E A A T AA TA DR E el ET e 395 Lo LO OM aeoea a a ra E a a EAN 395 FANGOM O A EE ESEE AA TEN TTE AE TEATR Cr tapa Ga EATE ford 396 random exponential random gamma random normal random poisson 396 random pxcor au e ale 0 a0ts 0 010 eee 397 ANDO MES CO ras A tees eect eh ee Ge eae eter eae Rote ed aes 397 random xcor random 00 ee 397 POAC HOM IP SUING ERR CEPE ORNE PR RPE O PERES RS SR PER PRE RO RP PERDER Ee 398 E E E day eld ARRENDAR EA 398 O 399 FEMOVO ar aa 399 TreMOVe QUPlICA eS ee 400 A A REAR RPPN RE RR RAD NR RR RR RR NR ROD 400 OO id Dl E NR 400 placita a a veers andres wed elias Ca NU TAS eae e ws tea dae ena iaa 401 POO ech sec Rr MPR AA EE PDR DERA USP O SEMDE RR DRA USOS 401 xxi NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary FESEL DErSHECHVE Discs 401 TOSCA di sue 401 FeSCEIMerR sis e AO A A BO RR ASR A O o Aa RA AAA e 402 SERT FASA L
150. NFO turtles die or are type turtle gt born lt name gt turtle 1 lt name gt lt action gt born lt action gt lt breed gt TURTLES lt breed gt lt event gt How to configure the logging output The default logging configuration netlogo_logging xml looks something like this NetLogo defines 8 loggers all descend directly from the root logger which means unless you explicitly set the properties appender layout and output level in the configuration they will inherit them from the root In the default configuration the root is set to level INFO the appender is org nlogo log XMLFileAppender and layout is org nlogo log XMLLayout Together these generate a nicely formatted XML file as defined in the netlogo_logging dtd which is based on the log4j dtd If the appender is a FileAppender including the XMLFileAppender a new file is start each time the user opens a model lt xml version 1 0 encoding UTF 8 gt lt DOCTYPE log4j configuration SYSTEM log4j dtd gt lt log4j configuration debug false xmlns log4j http jakarta apache org log4j gt lt appender name A1 class org nlogo log XMLFileAppender gt lt layout class org nlogo log XMLLayout gt lt appender gt lt category name org nlogo log Logger WIDGETS gt lt priority value off gt lt category gt lt category name org nlogo log Logger TURTLES gt lt priority value off gt lt category gt lt category na
151. NG NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE Log4j For logging NetLogo uses the Log4j library The copyright and license for the library are as follows Copyright 1999 2005 The Apache Software Foundation Licensed under the Apache License Version 2 0 the License you may not use this file except in compliance with the License You may obtain a copy of the License at http Awww apache org licenses LICENSE 2 0 Unless required by applicable law or agreed to in writing software distributed under the License is distributed on an AS IS BASIS WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND either express or implied See the License for the specific language governing permissions and limitations under the License PicoContainer For dependency injection NetLogo uses the PicoContainer library The copyright and license for the library are as follows Copyright c 2003 2004 PicoContainer Organization All rights reserved Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met e Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer e Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other mater
152. OOO AAA AAA ta eek 183 HiubNet Archneciure essa des li ie aid 183 Computer UDN tacita o A NA A EA SRS 184 PaL E E E Aa 184 CONS E EE E E dida 184 Requirements A e e e E ae e e Ea AnA Ean EERS 184 Starting an ACTIV DY A A O O 184 HubNet Control Det lado 185 Client Applets ia ii A SEO ta GT 186 Troubleshooting sorene a Ca DI pa ene OL eee a 186 Known Limitations e AE nro an nnn narran aran r nara 187 Galculator HubNet naaa ad 187 Calculator HubNet for Tl NavIgato Ecco oc rra 187 Teacher WOTKSOOPDS cocaina id AR AAA E AI aee Ri 188 HubNet Authoring QU nda Naa 188 Eina Mael o EE A iia 188 vi NetLogo 4 1 2 User Manual Table of Contents HubNet Authoring Guide areren renren excssaacnnsuceoensassiacchcwetuendtcaucnusvaczacessssnaspacctesceusaviaviaee 189 General HubNet Information eretas eae aerea ear cano nanacancnnancnnns 189 Coding HubNet Activities cria dais 189 O A O E A AS 189 Receiving messages from ClientS cooooooooocnncccnononoconnnonnnnnnnnnononnnnnnnnnocnnnnn non nnnnncnnnanannns 190 SONGING messages to cli caia GO Dadas Fita 192 Example tasas areia aio asia ba 192 Calculator HubNet Information resetar trees cano nana cana nnnananas 193 Computer HubNet lO cassar engra ada Da ao Sa ga 193 How To Make a Client INterface ooocccccnnncccnnncnocinononaconononanonononanananonananann nana canonanananes 193 View Updates on the Clients csi ar diria cb 193 Clicking in the View on ClientS
153. PEET 224 SO Zi lcd lea 224 MO A A A DNS 225 THE CHOW TITS UIDs a AAA a 225 A Gee ae gta o do RE NRO RUE NOE RCE De a RTOS A DAD A lo DA e A alo 226 WOFG GOD th ios diana dada iaa 226 DA A A NN A Dist oer 226 ZOO a a RD RAR RD PR OR O a id ia 226 EXTENSIONS GUIGC i ceic E E E A A cout a sd co casa ssiDa ais svaguardzeh E A LS UNE CN CE aduebenasaetacsezveree 229 USING EXTENSIONS ia as ais ndadoa uni AA aa aE A A AA 229 Where extensions are located street nono nara non ncn narra nana 229 APIS a A aa 230 Writing Extensions omita aE Aaa a a aae aaae ae del a E E a Eee Eain ieas 230 Summasen a 230 Examples iha io E 230 TOMA EEEE cat PEE SE E E ee E EEN E E A AE A TNE 231 Scala Tutorial E a E E ETA A E A EE Da 234 Extension development tipS cccccccccccccccccnnnnnnncnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnss 236 CONGCIUSION a EEEE DEEE EEA EN TEER ETEA EE NET 237 Array and Table EXtenslonsy sisisi ia ieaiaia aa ie 239 When to RU Fes SRD poa it A A A AS AA A E CR 239 HOWTO USE een a De aa Ota a eee DES a da Dn Ea ad 239 Limitation on table keyS coccccccconcconoconononononononnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnninnniss 239 vili NetLogo 4 1 2 User Manual Table of Contents Array and Table Extensions Array exa iii a 239 Table example eres imeso nais des ate Sava E EEEa aa isa UGT Ea dara relata 240 Array primitives ee 240 ALAN A ia 240 ACA ds A iain AA ERROS iD 2
154. RAR RI A a E VE 322 IN 75 ie used det dea AR E E OR RR CERA CURE EA RR RE IR RR 322 approximate hsb ee 322 approximale Qh vase a Aca 323 Arithmetic Operators LN lt gt l lt 55 earreta ana 323 COMA AI GORRO DRT reer ere 329 cleaprallCa esa ts 329 CISA All OTS dad dada 330 clear drawing Cid iio 330 clear Inks coh A A A A AA a 330 clear OULDUb cai e ta 330 Clear paicheS CN a A E bd 330 xvi NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary COEM iii A ene ere Tae 330 clear lle Ci rita 331 A O Pe ORB A A A CA RO 331 A Rd 331 CO AA AAA a A Dad a a aad eRe a 332 create ordered turtles cro create ordered lt breedS gt ooccccccccnnoncnnncnonancnnnnncnnnanananannnn 332 create lt breed gt to create lt breeds gt to create lt breed gt from create lt breeds gt from create lt breed gt with create lt breeds gt with create link to create links to create link from create links from create link with create links with 332 create turtles crt create lt breedsa tese ona nnn nn nnn nan nn non na non ana arenas 334 create temporary plot pen eee ear rr 335 RD PEQ PERENE DAR A NESSA RO PARAN DE O 335 Aate anG time 2 ARA A A A ee a E 335 UN es cen a aaa als tienes ast a o dae ota amp ain da ata Ui Nate 335 UTS Gis acaso a dt e See a haa 336 GUTUS C4 tin baits Miata Math alate id 336 directed link breed oia See T
155. Remember that a turtle related primitive might still be used by patches or the observer and vice versa To see which agents turtles patches links observer can actually run a primitive consult its dictionary entry Turtle related back bk lt breeds gt at lt breeds gt here lt breeds gt on can move clear turtles ct create lt breeds gt create ordered lt breeds gt create ordered turtles cro create turtles crt die distance distancexy downhill downhill4 dx dy face facexy forward fd hatch hatch lt breeds gt hide turtle ht home inspect is lt breed gt is turtle jump layout circle left It move to myself nobody no turtles of other patch ahead patch at patch at heading and distance patch here patch left and ahead patch right and ahead pen down pd pen erase pe pen up pu random xcor random ycor right rt self set default shape __set line thickness setxy shapes show turtle st sprout sprout lt breeds gt stamp stamp erase subject subtract headings tie towards towardsxy turtle turile set turiles turiles at turtles here turiles on turtles own untie uphill uphill4 Patch related clear patches cp diffuse diffuse4 distance distancexy import pcolors import pcolors rgb inspect is patch myself neighbors neighbors4 nobody no patches of other patch patch at patch ahead patch at heading and distance patch here patch left and ahead patch right and ahead patch set patches patches own random pxcor random pycor self sprout
156. Reports a new matrix object consisting of a rectangular subsection of the given matrix The rectangular region is from row r1 up to but not including row r2 and from column c1 up to but not including column c2 Here is an example let m matrix from row list 1 2 3 4 5 6 7 8 9 print matrix submatrix m 0 1 2 3 matrix row start col start row end col end rows from 0 inclusive to 2 exlusive columns from 1 inclusive to 3 exclusive gt matrix 23 56 Matrix Extension 247 NetLogo 4 1 2 User Manual matrix times scalar matrix times scalar matrix factor Reports a new matrix which is the result of multiplying every entry in the original matrix by the given scaling factor matrix times matrix times m1 m2 Reports a matrix which is the result of multiplying matrix m1 by matrix m2 using standard matrix multiplication make sure your matrix dimensions match up matrix times element wise matrix times element wise m1 m2 Reports a matrix which is the result of multiplying each element of matrix m7 by the corresponding element in m2 Note m7 and m2 must have the same dimensions matrix plus scalar matrix plus scalar matrix number Reports a matrix which is the result of adding the constant number to each element of the given matrix matrix plus matrix plus m1 m2 Reports a matrix which is the result of adding each element of matrix m7 to the corresponding element in m2 Note m7 and m2 m
157. Requirements NetLogo runs on almost any current computer If you have any trouble with NetLogo not working write bugs ccl northwestern edu System Requirements Application Windows NetLogo runs on Windows 7 Vista 2000 and XP The NetLogo installer for Windows installs Java 6 for NetLogo s private use only Other programs on your computer are not affected Mac OS X Mac OS X 10 4 or newer is required NetLogo 4 0 was the last version to support 10 3 and 10 2 We recommend you use Software Update to ensure that you have the latest Java Other platforms NetLogo should work on any platform on which Java 5 or later is installed Java 6 or later is strongly recommended If you have any trouble you may want to make sure that you are using the official Java from Sun and not some alternate implementation You start NetLogo by running the provided netlogo sh script Double clicking NetLogo jar may appear at first to work but is not recommended System Requirements Saved Applets NetLogo models saved as Java applets should work in any web browser where Java 5 or later is installed System Requirements 3D Occasionally an older less powerful system is not able to use the 3D view or NetLogo 3D Try it and see Some systems can use 3D but can t switch to full screen mode It depends on the graphics card or controller For example the ATI Radeon IGP 345 and Intel 82845 probably will not work Technical Java Details for W
158. See also patch at patch left and ahead patch right and ahead patch at heading and distance patch at patch at dx dy x Ed Reports the patch at dx dy from the caller that is the patch containing the point dx east and dy patches north of this agent Reporis nobody if there is no such patch because that point is beyond a non wrapping world boundary ask patch at 1 1 set pcolor green 7 if caller is a turtle or patch turns the mE patch just southeast of the caller green See also patch patch ahead patch left and ahead patch right and ahead patch at heading and distance patch at heading and distance patch at heading and distance heading distance patch at heading and distance reports the single patch that is the given distance from this turtle or patch along the given absolute heading In contrast to patch left and ahead and patch right and ahead this turtle s current heading is not taken into account Reports nobody if the patch does not exist because it is outside the world ask patch at heading and distance 90 1 set pcolor green 7 turns the patch 1 to the west of this patch green See also patch patch at patch left and ahead patch right and ahead patch here patch here patch here reports the patch under the turtle Note that this reporter isn t available to a patch because a patch can just say self NetLogo Dictionary 389 NetLogo 4 1 2 User Manual patch left and ahead patch right a
159. THOUT WARRANTIES OR CONDITIONS OF ANY KIND either express or implied See the License for the specific language governing permissions and limitations under the License 12 Copyright and License Information What s New Feedback from users is very valuable to us in designing and improving NetLogo We d like to hear from you Please send comments suggestions and questions to feedback ccl northwestern edu and bug reports to bugs ccl northwestern edu Version 4 1 2 December 2010 e fixes Windows installer now adds NetLogo 3D to the Start menu fixed BehaviorSpace issue where compile errors in experiment setups caused exceptions fixed regression in 4 1 1 where extension defined data types could cause errors in the GUI e g in agent monitors fixed extensions issues where NetLogo could get confused about what extensions are active fixed NetLogo 3D so the st amp command works for links fixed bug where pow primitive could give NaN result fixed bug where the F1 key didn t work on several primitives fixed bitmap extension so importing works in applets fixed bugs where typing certain combinations of keys or characters in the Command Center caused exceptions 4 fixed agentset building primitives to give correct error messages on invalid inputs fixed bug where logging of global variables didn t work under Java Web Start 4 fixed matrix extension issue where mat rix dimensions was incorrectly typed HubNet clients now
160. User Manual Previews As you draw your shape you will also see it in five smaller sizes in the five preview areas found near the bottom of the editing window The previews show your shape as it might appear in your model including how it looks as it rotates The number below each preview is the size of the preview in pixels When you edit the view patch size is also measured in pixels So for example the preview with 20 below it shows you how your shape would look on a turtle of size 1 on patches of size 20 pixels The rotatable feature can be turned off if you want a shape that always faces the same way regardless of the turtle s heading Overlapping shapes New elements go on top of previous elements You can change the layering order by selecting an element and then using the Bring to front and Send to back buttons Undo At any point you can use the Undo button to undo the edit you just performed Colors Elements whose color matches the Color that changes selected from a drop down menu the default is gray will change color according to the value of each turtle s color variable in your model Elements of other colors don t change For example you could create cars that always have yellow headlights and black wheels but different body colors Other buttons The Rotate Left and Rotate Right buttons rotate elements by 90 degrees The Flip Horizontal and Flip Vertical buttons reflect elements across the axes The
161. Von Neumann Example simpler code e BehaviorSpace fixes stop conditions now run without affecting the main random generator reduced memory usage when not generating spreadsheet output aborting an experiment no longer discards accumulated spreadsheet output 16 What s New NetLogo 4 1 2 User Manual the options for running from the command line have changed table output is no longer generated by default improved error reporting when running headless e extensions API the interfaces in org nlogo api involving agents and agentsets now have many additional methods extensions that define custom data types can now add support for import and export of those types extension primitives may now take a variable number of inputs an example extension written in Scala is now included Version 4 0 5 December 2009 e bugfixes Version 4 0 4 November 2008 e GIS extension for handling geographic data e applets now include powered by NetLogo notice linked to NetLogo site e bugfixes Version 4 0 September 2007 e features most models now run somewhat faster while results vary from model to model typical speedup is around 1 5x 0 the speedup comes from an improved compiler that now partially compiles NetLogo code into Java byte code 4 links are now their own type of agent alongside turtles and patches this is useful for network models geometry models and much else new Link Shapes Editor lets you contro
162. When you are finished using a file you can use the command file close to end your session with the file If you wish to remove the file afterwards use the primitive ile delete to delete it To close multiple opened files one needs to first select the file by using i1e open before closing it 7 Open 3 files file open myfilel txt file open myfile2 txt file open myfile3 txt Now close the 3 files file close file open myfile2 txt file close file open myfilel txt file close Or if you know you just want to close every file you can use file close all 124 Programming Guide NetLogo 4 1 2 User Manual Two primitives worth noting are file write and file read These primitives are designed to easily save and retrieve NetLogo constants such as numbers lists booleans and strings file write will always output the variable in such a manner that file read will be able to interpret it correctly file open myfile txt Opening file for writing ask turtles file write xcor file write ycor file close file open myfile txt Opening file for reading ask turtles setxy file read file read file close Code Examples File Input Example and File Output Example Letting the user choose The user directory user file and user new file primitives are useful when you want the user to choose a file or directory for your code to operate on Movies This section describes how to capture a QuickTime movie
163. Y OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE Colt Parts of NetLogo specifically the random gamma primitive are based on code from the Colt library http acs lbl gov hoschek colt The copyright for that code is as follows Copyright 1999 CERN European Organization for Nuclear Research Permission to use copy modify distribute and sell this software and its documentation for any purpose is hereby granted without fee provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation CERN makes no representations about the suitability of this software for any purpose It is provided as is without expressed or implied warranty MRJ Adapter NetLogo uses the MRJ Adapter library which is Copyright c 2003 2005 Steve Roy lt sroyOroydesign net gt The library is covered by the Artistic License MRJ Adapter is available from https mrjadapter dev java net Quaqua NetLogo uses the Quaqua Look and Feel library which is Copyright c 2003 2005 Werner Randelshofer http www randelshofer ch werner randelshofer bluewin ch All Rights Reserved The library is covered by the GNU LGPL Lesser General Public License The text of that license is included in the docs folder which accompa
164. a If you d like to make the window larger so that everything is easier to see you can use the zoom menu at the top of the window When you first open the model you will notice that the view is empty all black To begin the model you will first need to set it up Tutorial 1 Models 31 NetLogo 4 1 2 User Manual e Press the setup button What do you see appear in the view e Press the go button to start the simulation As the model is running what is happening to the wolf and sheep populations e Press the go button to stop the model Controlling the Model Buttons When a button is pressed the model responds with an action A button can be a once button or a forever button You can tell the difference between these two types of buttons by a symbol on the face of the button Forever buttons have two arrows in the bottom right corners like this Once buttons don t have the arrows like this Once buttons do one action and then stop When the action is finished the button pops back up Forever buttons do an action over and over again When you want the action to stop press the button again It will finish the current action then pop back up Most models including Wolf Sheep Predation have a once button called setup and a forever button called go Many models also have a once button called go once or step once which is like go except that it advances the model by one tick time step instead of over
165. a When you are reading in information from a file data that is stored in the file flows into your model On the other hand writing allows data to flow out of your model and into a file When a NetLogo model runs as an applet within a web browser it will only be able to read data from files which are in the same directory on the server as the model file Applets cannot write to any files When working with files always begin by using the primitive i1e open This specifies which file you will be interacting with None of the other primitives work unless you open a file first The next file primitive you use dictates which mode the file will be in until the file is closed reading or writing To switch modes close and then reopen the file The reading primitives include file read file read line file read characters and file at end Note that the file must exist already before you can open it for reading Code Examples File Input Example The primitives for writing are similar to the primitives that print things in the Command Center except that the output gets saved to a file They include file print file show file type and file write Note that you can never overwrite data In other words if you attempt to write to a file with existing data all new data will be appended to the end of the file If you want to overwrite a file use file delete to delete it then open it for writing Code Examples File Output Example
166. a 2 8 0 instead once it becomes available 1 Create extension folder Let s start with a new folder called example scala As with the Java example create src and classes sub folders 2 Write primitives and a Class Manager We ll put all of the source code in one file Here s the implementation of our reporter and our ClassManager in a file called src IntegerList scala import org nlogo api _ import org nlogo api Syntax _ import org nlogo api ScalaConversions _ class SampleScalaExtension extends DefaultClassManager def load manager PrimitiveManager manager addPrimitive first n integers new IntegerList class IntegerList extends DefaultReporter override def getSyntax reporterSyntax Array TYPE_NUMBER TYPE_LIST def report args Array Argument context Context AnyRef val n try fargs 0 getIntValue catch Case e LogoException gt throw new ExtensionException e getMessage if n lt 0 throw new ExtensionException input must be positive 234 Extensions Guide NetLogo 4 1 2 User Manual 0 until n toLogoList Mostly this is a straightforward line by line translation of the Java version One difference is worth noting In the Java version we explicitly converted ints to Double objects As previously mentioned all numbers used as NetLogo values must be of type Double even if they happen to have no fractional part In the Sca
167. a ees 336 display an A EA REA a bea nel ad qr desing 337 NELLE TN E parece eee IA Ad Pe eB e ao A OR Se ge Rae RE NE 338 o IKI E AEDA AA E EAA eden iira nd 338 downhill downhlS ss a cones atari A a AI aida 338 A TO 339 A A E TOS 339 210a oA AA O RI gaia a sees a Ca 339 OI ANDO ESSE Saas Aa A A A AA ESSA SED 339 e Fi ote vera ASR OR as 339 end RA E E ads GA o AA A Ad ente a A A A o e 340 OTOMANO cuidas 340 e e IN 340 REDA E E A ae Tie aie bt 4 341 export view export interface export output export plot export all plots export world 341 SXICHSIONS ses a a ia oka dS A e e lah 342 extract hs Denan A ND OO ae 342 SM AR 342 A en ds a A A AURA de e AAA A A A O AA O ro a 343 O NO 343 CON a talas 343 TEA A CE 343 SP uate ee q ca SDS cna Re A dia coa a 344 lesclosealdii a o NO Toda o EIA RI O 344 ERO EENE RGE O IN AA EAE AA dd 344 ete IS tt RR les id 344 HS US a A e Da da a Ce E TAT O 345 MEP RR DOE CURRAL RE ORAR ODE RR DR NR 345 fil print A END ARE PP RR ND PR RP UR RR REDE RS AE 345 Stade Doda sai a doe A ato alo a da ano ni Dorm da ERE RS do 346 IE 346 NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary xviii lee ads A A E 347 EA A RA 347 A A A E A O 347 EI Seen a A AA Don Son So LEOA OSSO SIGO A DA NAO as di 347 TMG actas tha A Doro Sana tases cu ER Sane ek A E A Sa a GS 348 A cual antera hers Sesto NE E ANET A etal ng cat cod aan ee SD JE a 348 MOORE eis ae saio tet As a chat als quado 348
168. a line to the top of your procedures tab extensions profiler If your model already uses other extensions then it already has an extensions line in it so just add profiler to the list For more information on using NetLogo extensions see the Extensions Guide Example setup 7 set up the model profiler start 7 Start profiling repeat 20 go 7 run something you want to measure profiler stop 77 stop profiling print profiler report view the results profiler reset clear the data Code Example Profiler Example Primitives profiler calls profiler exclusive time profiler inclusive time profiler start profiler stop profiler reset profiler report profiler calls profiler calls procedure name Reports the number of times that procedure name was called If procedure name is not defined then reports 0 Profiler Extension 275 NetLogo 4 1 2 User Manual profiler exclusive time profiler exclusive time procedure name Reports the exclusive time in milliseconds that procedure name was running for Exclusive time is the time from when the procedure was entered until it finishes but does not include any time spent in other user defined procedures which it calls If procedure name is not defined then reports 0 profiler inclusive time profiler inclusive time procedure name Reports the inclusive time in milliseconds that procedure name was running for Inclusive time is the time from when the procedure was entered until i
169. ace errei 305 Can make my model available as an applet while keeping the code secret 305 Can a model saved as an applet use import world file open and other commands A 306 When tried loading my model as an applet get an error like java lang ClassFormatError Incompatible magic ValU oococccccccnonococoncnoncccnanannns 306 A O O O A 306 Can run NetLogo from a CD a network drive or a USB driVe B cccccccnnnnoconccccnnnnoos 306 Why is NetLogo so much slower when unplug my Windows laptop 306 How come NetLogo won t start up on my Linux Machi PP ooooooocccnnnccccnonoconnncncncnonananons 307 When try to start NetLogo on Windows get an error The JVM could not be Started Help RAMAN PRI ET E 307 Can run NetLogo from the command line without the GUI ecceeeeteeeeeeees 307 Does NetLogo take advantage of multiple processorST oooooccooncccnnnncccnonanonononnncnnnnnannns 307 Can distribute NetLogo model runs across a cluster or grid of computers 308 Is there any way to recover lost work if NetLogo crashes or freezes 308 USADO saia ra Rua EE a Da ADO RUAS ABr DSO aa 308 When move the speed slider all the way to the right why does my model seem to SIOPS Edie a Rh a O E ER 308 Can use the mouse to paint in the View ccccccnnnoncconcccnccnnnnannnonnnnncnonanannnonencnnnnnn 308 How big can my model be How man
170. ack on and also forces an immediate update unless the user is fast forwarding the model using the speed slider Tick based updates As discussed above in the Tick Counter section in many NetLogo models time passes in discrete steps called ticks Typically you want the view to update once per tick between ticks That s the default behavior with tick based updates If you want additional view updates you can force an update using the display command The update may be skipped if the user is fast forwarding the model using the speed slider You don t have to use the tick counter to use tick based updates If the tick counter never advances the view will update only when you use the display command If you move the speed slider to a faster setting NetLogo will skip some of the updates that would ordinarily have happened Moving the speed slider to a slower setting doesn t cause additional updates rather it makes NetLogo pause after each update The slower the setting the longer the pause Even under tick based updates the view also updates whenever a button in the interface pops up both once and forever buttons and when a command entered in the Command Center finishes So it s not necessary to add the display command to once buttons that don t advance the tick counter Many forever buttons that don t advance the tick counter do need to use the display command An example in the Models Library is the Life model under Computer Scie
171. ag Example lt experiments gt lt experiment name experiment repetitions 10 runMetricsEveryStep true gt lt setup gt setup lt setup gt lt go gt go lt go gt lt exitCondition gt not any fires lt exitCondition gt lt metric gt burned trees lt metric gt lt enumeratedValueSet variable density gt lt value value 40 gt lt value value 0 1 gt lt value value 70 gt lt enumeratedValueSet gt lt experiment gt lt experiments gt In this example only one experiment setup is given but you can put as many as you want between the beginning and ending experiments tags Between looking at the DTD and looking at examples you create in the GUI it will hopefully be apparent how to use the tags to specify different kind of experiments The DTD specifies which tags are required and which are optional which may be repeated and which may not and so forth When XML for experiment setups is included in a model file it does not begin with any XML headers because not the whole file is XML only part of it If you keep experiment setups in their own file separate from the model file then the extension on the file should be xml not nlogo and you ll need to begin the file with proper XML headers as follows lt xml version 1 0 encoding us ascii gt lt DOCTYPE experiments SYSTEM behaviorspace dtd gt The second line must be included exactly as shown In the first line you may sp
172. age of the mathematical operations associated with matrices For instance matrix multiplication is a convenient way to perform geometric transformations and the repeated application of matrix multiplication can also be used to simulate other dynamic processes for instance processes on graph network structures If you d like to know more about matrices and how they can be used you might consider a course on linear algebra or search the web for tutorials The matrix extension also allows you to solve linear algebraic equations specified in a matrix format and even to identify trends in your data and perform linear ordinary least squares regressions on data sets with multiple explanatory variables How to use The matrix extension comes preinstalled since NetLogo 4 1 1 it was not in the initial 4 1 release To use the matrix extension in your model add a line to the top of your procedures tab extensions matrix If your model already uses other extensions then it already has an extensions line in it so just add matrix to the list For more information on using NetLogo extensions see the Extensions Guide Matrix example let m matrix from row list 1 2 3 4 5 6 print m gt matrix HEL 2307 As e JF print matrix pretty print text m gt Loko 22 3 1 4 5 6 print matrix dimensions m gt 2 3 7 NOTE row amp column indexing starts at 0 not 1 print matrix get m 1 2 what number is i
173. ain a copy of the License at http www apache org licenses LICENSE 2 0 Unless required by applicable law or agreed to in writing software distributed under the License is distributed on an AS IS BASIS WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND either express or implied See the License for the specific language governing permissions and limitations under the License Apache Jakarta HttpClient Copyright 1999 2007 Apache Software Foundation Licensed under the Apache License Version 2 0 the License you may not use this file except in compliance with the License You may obtain a copy of the License at http www apache org licenses LICENSE 2 0 Unless required by applicable law or agreed to in writing software distributed under the License is distributed on an AS IS BASIS WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND either express or implied See the License for the specific language governing permissions and Copyright and License Information 11 NetLogo 4 1 2 User Manual limitations under the License Apache Commons Logging Copyright 2003 2007 Apache Software Foundation Licensed under the Apache License Version 2 0 the License you may not use this file except in compliance with the License You may obtain a copy of the License at http www apache org licenses LICENSE 2 0 Unless required by applicable law or agreed to in writing software distributed under the License is distributed on an AS IS BASIS WI
174. ake sure to provide installation instructions Supporting old Java versions NetLogo works with Java 5 and later If you want your extension to be usable by all NetLogo users your extension should support Java 5 The easiest way is to accomplish this is do all your development with the Java 5 JDK It s also possible to develop for Java 5 using the Java 6 or later compiler but you need to do two things e Use the source 1 5 target 1 5 options to javac or equivalent in your IDE to tell the newer compiler to emit class files that are compatible with the older Java versions This ensures that your code doesn t use any Java 6 or later only Java language features e Use the bootclasspath option to javac or IDE equivalent to compile against the Java 5 class libraries Note that this requires installing Java 5 anyway Or if you re on Mac OS X 10 6 you can t actually install Java 5 so you ll have to get a copy of the Java 5 libraries from an older Mac OS X version or from a Java installation bundle for Linux This ensures that your code doesn t make any Java 6 or later only Java API calls Conclusion Don t forget to consult the NetLogo API Specification for full details on these classes interfaces and methods Note that there is no way for the modeler to get a list of commands and reporters provided by an extension so it s important that you provide adequate documentation The extensions facility is not yet complete The API doe
175. all patches ask all patches which is a common mistake to make if you re not careful about which agents will run the code you are writing Note Only the agents that are in the agentset at the time the ask begins run the commands ask concurrent ask concurrent agentset commands The agents in the given agentset run the given commands using a turn taking mechanism to produce simulated concurrency See the Ask Concurrent section of the Programming Guide for details on how this works Note Only the agents that are in the agentset af the time the ask begins run the commands See also without interruption at points agentset at points x1 y1 x2 y2 Reports a subset of the given agentset that includes only the agents on the patches the given distances away from this agent The distances are specified as a list of two item lists where the two items are the x and y offsets If the caller is the observer then the points are measured relative to the origin in other words the points are taken as absolute patch coordinates 324 NetLogo Dictionary NetLogo 4 1 2 User Manual If the caller is a turtle the points are measured relative to the turtle s exact location and not from the center of the patch under the turtle ask turtles at points 2 4 1 2 10 15 fa 1 7 only the turtles on the patches at the distances 2 4 1 2 and 10 15 relative to the caller mov atan atan x y Converts x and y of
176. alled NetLogo On some systems you can test the applet locally on your computer before uploading it to a web server It doesn t work on all systems though so if it doesn t work from your hard drive please try uploading it to a web server You don t need to include everything in the html file in your page If you want you can just take the HTML code beginning with lt applet gt and ending with lt applet gt and paste it into any HTML file you want It s even OK to put multiple lt applet gt tags on a single page Additional files Applets can read files on the web server If your applet requires additional files such as text files it reads images it imports and so on you will also need to put those files in the same folder These files should appear in the same location relative to the model file as they appear on your computer Applets cannot read or write files on the user s computer only the web server Applets cannot browse web server or the user s computer meaning that user file and user new file do nothing in an applet All files required to run your model including the model file itself and NetLogoLite jar must be readable by the web server user Extensions Many extensions can be used in applets Simply place the folder containing the extension jar in the same folder as the model Extensions that require native libraries don t work from applets This includes the QTJ and GoGo extensions Using an alternate jar locati
177. already using the GNU version by typing tar version and seeing if the output says tar GNU tar 304 FAQ Frequently Asked Questions NetLogo 4 1 2 User Manual How do install NetLogo unattended It depends on which platform you are using e Linux Untar NetLogo into the appropriate place Mac Copy the NetLogo directory from the disk image into the Applications folder e Windows Run the installer from the command line using the q option NetLogo4 1 2Installer exe q On Windows how do configure the Java installation that the without Java installer uses The without Java installer automatically searches for appropriate Java installations on your machine If you wish to direct NetLogo to a particular installation you may do so by setting the environment variable NETLOGO_JAVA to the full path of the installation e Go to the Start Menu gt Control Panel gt System e Switch to the Advanced panel e Press the Environment Variables button e Add NETLOGO_JAVA as a variable and set the value to the path of the Java installation Applets tried to run one of the applets on your site but it didn t work What should do Current versions of NetLogo require that your web browser support Java 5 or later For more details about Java requirements see the Applet guide Some NetLogo applets may require more memory than the browser normally makes available See the memory section of the Applet guide for details on how to
178. ample if you wanted to put a histogram within your model you d look at Histogram Example to find out how HubNet Computer Activities This section contains participatory simulations for use in the classroom For more information about HubNet see the HubNet Guide What s Next If you want to learn how to explore models at a deeper level Tutorial 2 Commands will introduce you to the NetLogo modeling language In Tutorial 3 Procedures you can learn how to alter and extend existing models and build your own models 40 Tutorial 1 Models Tutorial 42 Commands In Tutorial 1 you had the opportunity to view some of the NetLogo models and you have successfully navigated your way through opening and running models pressing buttons changing slider and switch values and gathering information from a model using plots and monitors In this section the focus will start to shift ffom observing models to manipulating models You will start to see the inner workings of the models and be able to change how they look Sample Model Traffic Basic e Go to the Models Library File menu e Open up Traffic Basic found in the Social Science section e Run the model for a couple minutes to get a feel for it e Consult the Information tab for any questions you may have about this model In this model you will notice one red car in a stream of blue cars The stream of cars are all moving in the same direction Every so often they pi
179. an median list Reports the statistical median of the numeric items of the given list Ignores non numeric items The median is the item that would be in the middle if all the items were arranged in order If two items would be in the middle the median is the average of the two show median xcor of turtles 7 prints the median of all the turtles x coordinates member member value list member string1 string2 member agent agentset For a list reports true if the given value appears in the given list otherwise reports false For a string reports true or false depending on whether string1 appears anywhere inside string2 as a substring For an agentset reports true if the given agent is appears in the given agentset otherwise reports false 374 NetLogo Dictionary NetLogo 4 1 2 User Manual show member 2 1 2 3 gt true how member 4 1 2 3 gt false how member bat abate gt true how member turtle 0 turtles gt true how member turtle 0 patches gt false Ia Il a ll a ow See also position min min list Reports the minimum number value in the list It ignores other types of items show min xcor of turtles 7 prints the lowest x coordinate of all the turtles min n of min n of number agentset reporter Reports an agentset containing number agents from agentset with the lowest values of reporter The agentset is built by finding all the agents with the lowest value of
180. and undirected 1ink breed keywords directed link breed streets street undirected link breed friendships friendship once you have created a breeded link you cannot create unbreeded links and vice versa You can however have directed and undirected links in the same world just not in the same breed Unlike with turtle breeds the singular breed name is required for link breeds as many of the link commands and reports use the singular name such as lt 1ink breed gt neighbor The following primitives are also automatically available once you define a directed link breed create street from create streets from create street to create streets to in street neighbor in street neighbors in street from my in streets my out streets out street neighbor out street neighbors out street to And the following are automatically available when you define an undirected link breed create friendship with create friendships with friendship neighbor friendship neighbors friendship with my friendships Multiple link breeds may declare the same own variable but a variable may not be shared between a turtle breed and a link breed Programming Guide 105 NetLogo 4 1 2 User Manual Just as with turtle breeds the order in which link breeds are declared defines the order in which the links are drawn so the friendships will always be on top of streets if for some reason these breeds w
181. ands This turtle creates number new turtles Each new turtle inherits of all its variables including its location from its parent Exceptions each new turtle will have a new who number and it may be of a different breed than its parent if the hat ch lt breeds gt form is used The new turtles then run commands You can use the commands to give the new turtles different colors headings locations or whatever The new turtles are created all at once then run one ata time in random order If the hatch lt breeds gt form is used the new turtles are created as members of the given breed Otherwise the new turtles are the same breed as their parent hatch 1 It 45 fd 1 7 this turtle creates one new turtle 7 and the child turns and moves away hatch sheep 1 set color black 7 this turtle creates a new turtle 7 Of the sheep breed See also create turtles sprout heading heading MA This is a built in turtle variable It indicates the direction the turtle is facing This is a number greater than or equal to O and less than 360 O is north 90 is east and so on You can set this variable to make a turtle turn See also right left dx dy Example set heading 45 5 turtle is now facing northeast set heading heading 10 same effect as rt 10 hidden hidden aoe This is a built in turtle or link variable It holds a boolean true or false value indicating whether the turtle or link is cur
182. any different colors Since import pcolors sets the pcolor of patches agents can sense the image This is useful if agents need to analyze process or otherwise interact with the image If you want to simply display a static backdrop without color distortion see import drawing The following image file formats are supported BMP JPG GIF and PNG If the image format supports transparency alpha then all fully transparent pixels will be ignored Partially transparent pixels will be treated as opaque NetLogo Dictionary 359 NetLogo 4 1 2 User Manual import pcolors rgb import pcolors rgb filename ig Reads an image file scales it to the same dimensions as the patch grid while maintaining the original aspect ratio of the image and transfers the resulting pixel colors to the patches The image is centered in the patch grid Unlike import pcolors the exact colors in the original image are retained The pcolor variable of all the patches will be an RGB list rather than an approximated NetLogo color The following image file formats are supported BMP JPG GIF and PNG If the image format supports transparency alpha then all fully transparent pixels will be ignored Partially transparent pixels will be treated as opaque import world import world filename Reads the values of all variables for a model both built in and user defined including all observer turtle and patch variables from an external file named by the gi
183. any size or orientation Getting started To begin making shapes choose Turtle Shapes Editor or Link Shapes Editor in the Tools menu A new window will open listing all the shapes currently in the model beginning with default the default shape The Shapes Editor allows you to edit shapes create new shapes and borrow from another model You can also import turtle shapes from a library of pre existing shapes Importing shapes Every new model in NetLogo starts off containing a small core set of frequently used shapes Many more turtle shapes are available by using the Import from library button This brings up a dialog where you can select one or more shapes and bring them into your model Select the shapes then press the Import button Similarly you can use the Import from model button to borrow shapes from another model Default shapes Here are the turtle shapes that are included by default in every new NetLogo model First row default airplane arrow box bug butterfly car Second row circle circle 2 cow cylinder dot face happy face neutral Third row face sad fish flag flower house leaf line Shapes Editor Guide 155 NetLogo 4 1 2 User Manual Fourth row line half pentagon person plant sheep square square 2 Fifth row star target tree triangle triangle 2 truck turtle Sixth row wheel x Shapes library And here are the shapes in the shapes library including all of the default shapes too
184. ar to layout spring but with an added layer of complexity The turtles in turtle set attract and repel each other depending on the links that are in link set between them but there is also a magnetic field which the links try to align with The link set is the set of links that exert forces on the turtles they are connected to Turtles that are connected to links in the link agentset but are not included in the turtle agentset are treated as anchors If there are no turtles with fixed positions the entire network will probably collapse on itself spring constantis a measure of the tautness of the spring See layout spring NetLogo Dictionary 365 NetLogo 4 1 2 User Manual spring length is the zero force length or the natural length of the springs See layout spring repulsion constantis a measure of repulsion between the nodes See layout spring magnetic field strength is the force of the magnetic field Reasonable values range from 0 to 1 but 0 05 is a good default magnetic field type is a number in the range from 0 to 10 Choices are listed in the table below CPI SCSCOCSC CS S S SOUTHEAST 4 a CAN gt sommes SSCS ws S TAN T CONCENTRIC 10 Magnetic field runs clockwise around the origin in concentric circles If bidirectional is true then links try to align with the magnetic field by pushing attached turtles both in the direction of the field and in the opposite direction Otherwise the links just p
185. art a new model Nearly every model in our Models Library however uses tick based updates Continuous updates are simplest but tick based updates give you more control over when and how often updates happen It s important exactly when an update happens because when updates happen determines what you see on the screen If an update comes at an unexpected time you may see something unexpected perhaps something confusing or misleading It s also important how often updates happen because updates take time The more time NetLogo spends updating the view the slower your model will run With fewer updates your model runs faster Continuous updates Continuous updates are very simple With continuous updates NetLogo updates the view a certain number of times per second by default 50 times a second when the speed slider is in the default middle setting Programming Guide 117 NetLogo 4 1 2 User Manual If you move the speed slider to a slower setting NetLogo will update more than 50 times a second effectively slowing down the model On a faster setting NetLogo will update less than 50 times a second On the fastest setting updates will be separated by several seconds At extremely slow settings NetLogo will be updating so often that you will see your agents moving or changing color etc one at a time If you need to temporarily shut off continuous updates use the no display command The display command turns updates b
186. at agentsets are always in random order a different random order every time If you need your agents to do something in a fixed order you need to make a list of the agents instead See the Lists section below Breeds NetLogo allows you to define different breeds of turtles and breeds of links Once you have defined breeds you can go on and make the different breeds behave differently For example you could have breeds called sheep and wolves and have the wolves try to eat the sheep or you could have link breeds called streets and sidewalks where foot traffic is routed on sidewalks and car traffic is routed on streets You define turtle breeds using the breed keyword at the top of the Procedures tab before any procedures breed wolves wolf breed sheep a sheep You can refer to a member of the breed using the singular form just like the turtle reporter When printed members of the breed will be labeled with the singular name Some commands and reporters have the plural name of the breed in them such as create lt breeds gt Others have the singular name of the breed in them such as lt breed gt The order in which breeds are declared is also the order order in which they are layered in the view So breeds defined later will appear on top of breeds defined earlier in this example sheep will be drawn over wolves When you define a breed such as sheep an agentset for that breed is automatically created so that all of
187. at color will be shown against other colors In the bottom left the code for the currently selected color is displayed for example red 2 so you can copy and paste it into your code On the bottom right there are three increment options 1 0 5 and 0 1 These numbers indicate the difference between two adjacent swatches When the increment is 1 there are 10 different shades in each row when the increment is 0 1 there are 100 different shades in each row 0 5 is an intermediate setting Ask NetLogo uses the ask command to give commands to turtles patches and links All code to be run by turtles must be located in a turtle context You can establish a turtle context in any of three ways e In a button by choosing Turtles from the popup menu Any code you put in the button will be run by all turtles e In the Command Center by choosing Turtles from the popup menu Any commands you enter will be run by all the turtles e By using ask turtles The same goes for patches links and the observer except that you cannot ask the observer Any code that is not inside any ask is by default observer code 100 Programming Guide NetLogo 4 1 2 User Manual Here s an example of the use of ask in a NetLogo procedure to setup clear all crt 100 create 100 turtles with random headings ask turtles set color red turn them red fa 50 7 spread them around ask patches if pxcor gt 0 7 patches on the right side set pcolor g
188. atch So for example if turtle 0 nobody You could also use is turtle if is turtle turtle 0 Does NetLogo have arrays In the current version of NetLogo lists are immutable singly linked lists rather than having an array based underlying implementation as in earlier NetLogo versions True arrays are available by using the array extension See the Arrays amp Tables section of the User Manual FAQ Frequently Asked Questions 313 NetLogo 4 1 2 User Manual Does NetLogo have hash tables or associative arrays Yes using the table extension See the Arrays amp Tables section of the User Manual How can use different patch neighborhoods circular Von Neumann Moore etc The in radius primitives lets you access circular neighborhoods of any radius The neighbors primitive gives you a Moore neighborhood of radius 1 and the neighbors4 primitive gives you a Von Neumann neighborhood of radius 1 For Moore or Von Neumann neighborhoods of a larger radius see Moore amp Von Neumann Example in the Code Examples section of the Models Library How can convert an agentset to a list of agents or vice versa If you want the list in a particular order use the sort or sort by primitives The Lists section of the Programming Guide explains how to do this See also Ask Ordering Example in the Code Examples section of the Models Library If you want the list in a random order here s how self of lt ag
189. atch variable while this primitive copies values from a patch variable to a raster dataset gis turtle dataset gis turtle dataset turtle set Reports a new point VectorDataset built from the turtles in the given agentset The points are located at locations of the turtles translated from NetLogo space into GIS space using the current coordinate transformation And the dataset s properties consist of all of the turtle variables common to every turtle in the agentset gis link dataset gis link dataset link set Reports a new line VectorDataset built from the links in the given agentset The endpoints of each line are at the location of the turtles connected by each link translated from NetLogo space into GIS space using the current coordinate transformation And the dataset s properties consist of all of the link variables common to every link in the agentset VectorDataset Primitives gis shape type of gis shape type of VectorDataset Reports the shape type of the given dataset The possible output values are POINT LINE and POLYGON gis property names gis property names VectorDataset Reports a list of strings where each string is the name of a property possessed by each VectorFeature in the given VectorDataset suitable for use in gis property value gis feature list of gis feature list of VectorDataset Reports a list of all VectorFeatures in the given dataset gis vertex lists of gis vertex lists of VectorFeature
190. atch variables include pxcor and pycor There is a complete list here You can also define your own variables You can make a global variable by adding a switch or a slider to your model or by using the globals keyword at the beginning of your code like this globals score You can also define new turtle patch and link variables using the turtles own patches own and links own keywords like this turtles own energy speed patches own friction links own strength These variables can then be used freely in your model Use the set command to set them If you don t set them they ll start out storing a value of zero Global variables can be read and set at any time by any agent As well a turtle can read and set patch variables of the patch it is standing on For example this code ask turtles set pcolor red 96 Programming Guide NetLogo 4 1 2 User Manual causes every turtle to make the patch it is standing on red Because patch variables are shared by turtles in this way you can t have a turile variable and a patch variable with the same name In other situations where you want an agent to read a different agent s variable you can use of Example show color of turtle 5 7 prints current color of turtle with who number 5 You can also use of with a more complicated expression than just a variable name for example show xcor ycor of turtle 5 7 prints the sum of the x and y coordinates of t
191. ation of Euler s method Call this in your model s GO procedure to system dynamics go Compute variable and flow values once per step let local sheep births sheep births Step 2 NetLogo Integration Once you create an aggregate model with the System Dynamics Modeler you can interact with the model through the main NetLogo interface window Let s build our NetLogo model to run the code generated by our diagram We ll need a setup and go buttons which call the system dynamics setup and system dynamics go procedures created by the System Dynamics Modeler And we ll want a monitor and a plot to watch the changes in sheep population e Select the main NetLogo window e In the Procedures tab write to setup ca system dynamics setup end to go system dynamics go system dynamics do plot end e Move to the Interface tab e Create a setup button e Create a go button don t forget to make it forever System Dynamics Guide 179 NetLogo 4 1 2 User Manual e Create a sheep monitor e Create a plot called populations with a pen named sheep Now we re ready to run our model e Press the setup button e Don t press the go button yet Instead type go four or five times into the Command Center Notice what happens The sheep population increases exponentially After four or five iterations we have an enormous number of sheep That s because we have sheep reproduction but our sheep never die To fix that let s finis
192. bar allow you to control the view updates and various other model properties O Rea M view updates Fa Settings continuous a normal speed e The slider lets you control how fast the model runs Slower can be valuable since some models run so fast that it s hard to see what s going on You can also fast forward the model by moving the slider to the right and reducing the frequency of view updates e The view updates check box controls whether view updates happen at all e The update mode menu allows you to switch between continuous and tick based update modes e The Settings button allows you to change model settings Continuous updates means that NetLogo updates that is redraws the view many times a second regardless of what is going on in the model Tick based updates means that the view only updates when the tick counter advances For a fuller discussion of view updates see the Programming Guide The 2D and 3D Views The large black square in the Interface tab is the 2D view It s a visual representation of the NetLogo world of turtles and patches Initially it s all black because the patches are black and there are no turtles yet You can open the 3D View another visual representation of the world by clicking on the 3D button in the View Control Strip MAS tickso 30 The three sets of black arrows in the upper left let you change the size of the world When the origin is centered the wo
193. ber determines what color the turtle or link s label appears in if it has a label You can set this variable to change the color of a turtle or link s label 364 NetLogo Dictionary NetLogo 4 1 2 User Manual See also label plabel plabel color Example ask turtles set label color red all the turtles now have red labels last last list last string On a list reports the last item in the list On a string reports a one character string containing only the last character of the original string layout circle layout circle agentset radius layout circle list of turtles radius Arranges the given turtles in a circle centered on the patch at the center of the world with the given radius If the world has an even size the center of the circle is rounded down to the nearest patch The turtles point outwards If the first input is an agentset the turtles are arranged in random order If the first input is a list the turtles are arranged clockwise in the given order starting at the top of the circle Any non turtles in the list are ignored in random order layout circle turtles 10 5 in order by who number layout circle sort turtles 10 7 in order by size layout circle sort by size of 1 lt size of 22 turtles 10 __ layout magspring __layout magspring turtle set link set spring constant spring length repulsion constant magnetic field strength magnetic field type bidirectional Very simil
194. cal Temp On Mac OS 10 5 the temp directory varies for each user you can determine your temp directory by opening the Terminal application and typing Logging 195 NetLogo 4 1 2 User Manual echo STMPDIR at the prompt On Mac OS prior to 10 5 the temp directory is the same as on other Linux like systems tmp There are two convenience commands that will help you manage the logs zip log files filename will gather all the logs in the temp directory and put them in one zip file at the location specified After doing zip log files the existing logs are not deleted you can do so explicitly by using delete log files The following is a chart describing the name of the loggers available the type of events each logs at what level and provides a sample output using the XMLLayout All the loggers are found in org nlogo log Logger When referring to the loggers in the configuration file you should use the fully qualifie ed name So for example the logger GLOBALS would actually be org nlogo log Logger GLOBALS lt event logger org nlogo log Logger GLOBALS timestamp 1177341065988 l a global variable info al GLOBALS type globals gt changes debug lt name gt FOO lt name gt lt value gt 51 0 lt value gt lt event gt lt event logger org nlogo log Logger GREE timestamp 1177341065988 level INFO 3 type slider gt sliders switches lt action gt changed lt action gt choosers input lt name gt foo lt nam
195. cast is achieved by taking the In of Y See matrix regress below Because it is impossible to take the natural log of zero or a negative number matrix forecast continuous growth will result in an error if it finds a zero or negative number in data list 7 a continuous growth extrapolation of the next item in the list print matrix forecast continuous growth 20 25 28 32 35 39 gt 45 60964465307146 21 15254147944863 0 12805985615332668 0 9760867518334806 These results tell us 7 the next predicted value is approximately 45 610 the compound growth trend line is given by Y 21 1525 e 0 1281 t 77 Y grows by approximately 12 81 each period if compounding takes place continuously 77 the R 2 value is roughly 0 9761 a good fit Matrix Extension 251 NetLogo 4 1 2 User Manual matrix regress matrix regress data matrix All three of the forecast primitives above are just special cases of performing an OLS ordinary least squares linear regression the matrix regress primitive provides a flexible general purpose approach The input is a matrix data matrix with the first column being the observations on the dependent variable and each subsequent column being the observations on the 1 or more independent variables Thus each row consists of an observation of the dependent variable followed by the corresponding observations for each independent variable The output is a Logo nested list composed of two elemen
196. ce write hello world gt hello world See also print show and type See also output write X xcor xcor x This is a built in turtle variable It holds the current x coordinate of the turtle You can set this variable to change the turtle s location This variable is always greater than or equal to min pxcor 0 5 and strictly less than max pxcor 0 5 See also setxy ycor pxcor pycor xor boolean1 xor boolean2 Reports true if either boolean1 or boolean2 is true but not when both are true if pxcor gt 0 xor pycor gt 0 set pcolor blue 7 upper left and lower right quadrants turn blue Y ycor 430 NetLogo Dictionary NetLogo 4 1 2 User Manual ycor This is a built in turtle variable It holds the current y coordinate of the turtle You can set this variable to change the turtle s location This variable is always greater than or equal to min pycor 0 5 and strictly less than max pycor 0 5 See also setxy xCOr pxcor pycor 2 1 2 3 ane 21 22 23 These are special local variables They hold the current inputs to a reporter or command block for certain primitives for example the current item of a list being visited by foreach or map is always equivalent to 1 You may not set these variables and you may not use them except with certain primitives currently foreach map reduce filter sort by and n values See those entries for example usage
197. cel Apply OK What are the current settings for max pxcor min pxcor max pycor min pycor and Patch size e Press cancel to make this window go away without changing the settings e Place your mouse pointer next to but still outside of the view You will notice that the pointer turns into a crosshair e Hold down the mouse button and drag the crosshair over the view Tutorial 1 Models 37 NetLogo 4 1 2 User Manual The view is now selected which you know because it is now surrounded by a gray border e Drag one of the square black handles The handles are found on the edges and at the corners of the view e Unselect the view by clicking anywhere in the white background of the Interface tab e Press the Settings button again and look at the settings What numbers changed What numbers didn t change The NetLogo world is a two dimensional grid of patches Patches are the individual squares in the grid In Wolf Sheep Predation when the grass switch is on the individual patches are easily seen because some of them are green while others are brown Think of the patches as being like square tiles in a room with a tile floor By default exactly in the middle of the room is a tile labeled 0 0 meaning that if the room was divided in half one way and then the other way these two dividing lines would intersect on this tile We now have a coordinate system that will help us locate objects within
198. center position the model will gradually run faster or slower At very high speeds view updates become very infrequent and may be separated by several seconds It may feel like the model is actually running slower since the updates are so infrequent But watch the tick counter or other indicators such as plots and you ll see that yes the model really is running faster If the infrequent updates are disconcerting don t push the slider so far over When using tick based updates slowing the model down does not cause additional view updates Rather NetLogo simply pauses after each tick When using continuous updates slowing the model down means view updates become more closely spaced If you push the speed slider more than halfway to the left the model will be running so slowly that you can watch turtles moving one at a time This is new in NetLogo 4 0 in previous NetLogo versions no matter how slowly you ran a model you would never see the agents in an ask moving one at a time all the agents in an ask always appeared to move together Numbers NetLogo no longer maintains an internal distinction between integers and floating point numbers So for example Old observer gt print 3 3 observer gt print 3 0 3 0 observer gt print 1 2 3 observer gt print 1 5 1 5 33 0 observer gt print 3 true ll w o The last line shows that although the distinction between integer 3 and floating point 3 0 was maintained the
199. change the memory allocation When running my model as an applet get the following error java lang OutOfMemoryError Java heap space The Java Plug In is not allocating sufficient space to run the model Details on how big a model can be in NetLogo can be found here You will need to increase the amount of memory available to the Java Plug In See the instructions here Can make my model available as an applet while keeping the code secret No In order for the applet to operate the model file must be accessible also FAQ Frequently Asked Questions 305 NetLogo 4 1 2 User Manual When you use Save as applet on the File menu the HTML page generated contains the source code and a link where the user can download the model file If you want you can remove the source code and the link Removing the link will make it harder for the user to access the model file but not impossible Can a model saved as an applet use import world file open and other commands that read files Yes but only to read files that are stored in the same directory on your web server as the HTML and model files Unsigned Java applets cannot read files on the user s computer only the web server When tried loading my model as an applet get an error like java lang ClassFormatError Incompatible magic value If your web server returns custom error messages in response to requests for non existent pages it must also return a status code of 404 Not
200. ches is determined by the settings min pxcor max pxcor min pycor and max pycor When NetLogo starts up min pxcor max pxcor min pycor and max pycor are 16 16 16 and 16 respectively This means that pxcor and pycor both range from 16 to 16 so there are 33 times 33 or 1089 patches total You can change the number of patches with the Settings button Turtles have coordinates too xcor and ycor A patch s coordinates are always integers but a turtle s coordinates can have decimals This means that a turtle can be positioned at any point within its patch it doesn t have to be in the center of the patch Links do not have coordinates instead they have two endpoints each a turtle Links appear between the two endpoints along the shortest path possible even if that means wrapping around the world The way the world of patches is connected can change By default the world is a torus which means it isn t bounded but wraps so when a turtle moves past the edge of the world it disappears and reappears on the opposite edge and every patch has the same number of neighbor patches if you re a patch on the edge of the world some of your neighbors are on the opposite edge However you can change the wrap settings with the Settings button If wrapping is not allowed in a given direction then in that direction x or y the world is bounded Patches along that boundary will have fewer than 8 neighbors and turtles will not move beyond the ed
201. ck could help with troubleshooting After switching to continuous updates you may want to use the speed slider to slow the model down until you see your agents moving one at a time Don t forget to change back to tick based updates when you are done as the choice of update mode is saved with the model Plotting NetLogo s plotting features let you create plots to help you understand what s going on in your model Before you can plot you need to create one or more plots in the Interface tab Each plot should have a unique name You ll be using its name to refer to it in your code in the Procedures tab For more information on using and editing plots in the Interface tab see the Interface Guide Specifying a plot If you only have one plot in your model then you can start plotting to it right away But if you have more than one plot you have to specify which one you want to plot to To do this use the set current plot command with the name of the plot enclosed in double quotes like this set current plot Distance vs Time You must supply the name of the plot exactly as you typed it when you created the plot Note that later if you change the name of the plot you ll also have to update the set current plot calls in your model to use the new name Copy and paste can be helpful here Specifying a pen When you make a new plot it just has one pen in it If the current plot only has one plot pen then you can start plotting to it rig
202. clients send sends to one client or a selected group As suggested earlier nothing on the client updates automatically If a value changes on the server it is your responsibility as the activity author to update monitors on the client For example say you have a slider on the client called step size and a monitor called Step Size note that the names must be different you might write updating code like this if hubnet message tag step size ask student with user id hubnet message source set step size hubnet messag hubnet send user id Step Size step siz You can send any type of data you want numbers strings lists lists of lists lists of strings however if the data is not appropriate for the receiving interface element say if you were to send a string to a slider the message will be ignored Here are a few code examples for different types of data data type hubnet broadcast example hubnet send example t broadcast A 3 14 t send jimmy A 3 14 t broadcast STR1 t send M4 2 TB STR ERE I THERE t send t message source L2 e t broadcast e t broadcas t send susie 41 1 t broadcast t send teacher user names 3Jimmy user names jimmy susie susie bob george bob george Examples Study the models in the HubNet Computer Activities and the HubNet Calculator A
203. collaborate on such a venture please let us know We would welcome it Is NetLogo available in a Spanish version Chinese version your language here version etc At present NetLogo is available only in English We plan to eventually make it possible for users to produce their own foreign language packs for NetLogo and share them with each other In order to do this we need to separate all of the English text from the rest of the source code so that is separately editable We re not sure when this will happen The user manual has been translated into Chinese and Czech The translated versions are available from the NetLogo web site Is NetLogo compiled or interpreted Short answer partially compiled we are working towards a full compiler Long answer NetLogo does include a compiler that generates Java byte code However this compiler does not yet support the entire language so some parts of user code are interpreted We are working on expanding the compiler to support the entire language Note that our compiler generates Java byte code and Java virtual machines have just in time compilers that in turn compile Java byte code all the way to native code so much user code is ultimately translated to native code Has anyone built a model of lt x gt Try looking at the NetLogo Models Library our Community Models page and our list of references to NetLogo in outside works You might also ask the question on the NetLogo U
204. colors import pcolors rgb import world mouse down mouse inside mouse xcor mouse ycor output print output show output type output write print read from string reset timer set current directory show timer type user directory user file user new file user input user message user one of user yes or no write File file at end file close file close all file delete file exists file flush file open file print file read file read characters file read line file show file type file write user directory user file user new file List but first but last e mpty filter first foreach oe histogram is list last engin list a ap replace it item reverse sentence shuffle E sort sort by sublisi sublist 318 NetLogo Dictionary NetLogo 4 1 2 User Manual String Operators lt gt lt gt but first but last empty first is string item last length member position remove remove item read from string replace item reverse substring word Mathematical abs acos asin atan ceiling cos e exp floor int is number In log max mean median min mod modes new seed pi precision random random exponential random float random gamma random normal random poisson random seed remainder round sin sqrt standard deviation subtract headings sum tan variance Plotting autoplot auto plot off auto plot on clear all plots clear plot create temporary plot pen export plot export all plots histogram plot plot name plot pen
205. command file close to close an opened file before deletion Note that the string can either be a file name or an absolute file path If it is a file name it looks in whatever the current directory is This can be changed using the command set current directory It is defaulted to the model s directory file exists file exists string Reports true if string is the name of an existing file on the system Otherwise it reports false Note that the string can either be a file name or an absolute file path If it is a file name it looks in whatever the current directory is This can be changed using the command set current directory It defaults to to the model s directory 344 NetLogo Dictionary NetLogo 4 1 2 User Manual file flush file flush Forces file updates to be written to disk When you use file write or other output commands the values may not be immediately written to disk This improves the performance of the file output commands Closing a file ensures that all output is written to disk Sometimes you need to ensure that data is written to disk without closing the file For example you could be using a file to communicate with another program on your machine and want the other program to be able to see the output immediately file open file open string This command will interpret string as a path name to a file and open the file You may then use the reporters file read file read line and file read characters to read i
206. command itself in turn causing the turtles to run commands e setxy random xcor random ycor is a command using reporters A reporter as opposed to a command reports a result First each turtle runs the reporter random xcor which will report a random number from the allowable range of turtle coordinates along the X axis Then each turtle runs the reporter random ycor same for the Y axis Finally each turtle runs the setxy command with those two numbers as inputs That makes the turtle move to the point with those coordinates e end completes the definition of the setup procedure When you re done typing switch to the Interface tab and press the setup button you made before You will see the turtles scattered around the world Press setup a couple more times and see how the arrangement of turtles is different each time Note that some turtles may be right on top of each other Think a bit about what you needed to do to make this happen You needed to make a button in the interface and make a procedure that the button uses The button only worked once you completed both of these separate steps In the remainder of this tutorial you will often have to complete two or more similar steps to add another feature to the model If something doesn t appear to work after you completed what you thought is the final step for that new feature continue to read ahead to see if there is still more to do After reading ahead for a couple of paragraph
207. cond if the seed for the current millisecond was already used See also random seed no display no display Turns off all updates to the current view until the display command is issued This has two major uses One you can control when the user sees view updates You might want to change lots of things on the view behind the user s back so to speak then make them visible to the user all at once Two your model will run faster when view updating is off so if you re in a hurry this command will let you get results faster Note that normally you don t need to use no display for this since you can also use the on off switch in view control strip to freeze the view NetLogo Dictionary 383 NetLogo 4 1 2 User Manual Note that display and no display operate independently of the switch in the view control strip that freezes the view See also display nobody nobody This is a special value which some primitives such as turtle one of max one of etc report to indicate that no agent was found Also when a turtle dies it becomes equal to nobody Note Empty agentsets are not equal to nobody If you want to test for an empty agentset use any You only get nobody back in situations where you were expecting a single agent not a whole agentset set other one of other turtles here if other nobody ask other set color red no links no links Reports an empty link agentset no patches no patches
208. crete steps called ticks NetLogo includes a built in tick counter so you can keep track of how many ticks have passed The current value of the tick counter is shown above the view You can use the Settings button to hide the tick counter or change the word ticks to something else In code to retrieve the current value of the tick counter use the ticks reporter The tick command advances the tick counter by 1 The clear a11 command resets the tick counter to O If you want to reset the counter to O without clearing everything use the reset ticks command If your model is set to use tick based updates then the tick command will usually also update the view See the next section View Updates When to tick We suggest using the tick command after your agents have completed all their movements and actions but before you plot or calculate statistics That way if the plotting or calculating code refers to the tick counter it will get the new value reflecting that the tick is now complete Example to go ask turtles move ask patches grow tick do plots end to do plots plotxy ticks count turtles end 116 Programming Guide NetLogo 4 1 2 User Manual By putting tick before do plots the plotting code gets the right value of the tick counter when it uses the ticks reporter Fractional ticks In most models the tick counter starts at O and goes up 1 at a time from integer to integer But it s also pos
209. crt 100 setxy random float min pxcor random float min pycor 7 distributes 100 turtles randomly in the 7 third quadrant See also max pxcor max pycor world width and world height mod number1 mod number2 Reports number modulo number2 that is the residue of number1 mod number2 mod is is equivalent to the following NetLogo code numberl floor numberl number2 number2 Note that mod is infix that is it comes between its two inputs show 62 mod 5 gt 2 show 8 mod 3 gt i See also remainder mod and remainder behave the same for positive numbers but differently for negative numbers modes modes list Reports a list of the most common item or items in list The input list may contain any NetLogo values 376 NetLogo Dictionary NetLogo 4 1 2 User Manual If the input is an empty list reports an empty list show modes 1 2 2 3 4 gt 2 show modes 1 2 2 3 3 4 gt 2 3 show modes 1 2 3 1 2 3 2 3 4 gt 11 2 311 show modes pxcor of turtles shows which columns of patches have the most turtles on them mouse down mouse down Reports true if the mouse button is down false otherwise Note If the mouse pointer is outside of the current view mouse down will always report false mouse inside mouse inside Reports true if the mouse pointer is inside the current view false otherwise mouse xcor mouse ycor mouse xcor mouse ycor Reports the x
210. crt gives the new turtles random colors and random integer headings cro assigns colors sequentially and gives the turtles sequential equally spaced headings with the first turtle facing north heading of 0 Prior to NetLogo 4 0 the crt command behaved the way cro does now If your old model depends on the ordered behavior you will need to change your code to use cro instead of crt It is common for old models that used crt to contain extra commands to randomize the new turtles headings for example rt random 360 or set heading random 360 These commands are no 142 Transition Guide NetLogo 4 1 2 User Manual longer necessary when used inside crt Adding strings and lists Prior to NetLogo 4 0 the addition operator could be used to concatenate strings and join lists In current NetLogo only works on numbers To concatenate strings use the word primitive to join lists together use the sentence primitive This language change was made to increase the speed of code that uses Old code print There are count turtles turtles New code print word There are count turtles turtles Likewise if you need to concatenate lists use SENTENCE This change is not handled automatically when converting old models users will need to change their code by hand We know this change will be awkward for users who are used to the old syntax We have made this change for efficiency and consistency We can implement an
211. ctivities sections of the Models Library to see how these primitives are used in practice in the Procedures window Disease is a good one to start with 192 HubNet Authoring Guide NetLogo 4 1 2 User Manual Calculator HubNet Information For information on writing HubNet activities using calculator clients please contact us Computer HubNet Information The following information is specific to Computer HubNet How To Make a Client Interface Open the HubNet Client Editor found in the Tools Menu Add any buttons sliders switches monitors plots choosers or notes that you want just as you would in the interface tab You ll notice that the information you enter for each of the widgets is slightly different than in the Interface panel Widgets on the client don t interact with the model in the same way Instead of a direct link to commands and reporters the widgets send messages back to the server and the model then determines how those messages affect the model All widgets on the client have a tag which is a name that uniquely identifies the widget When the server receives a message from that widget the tag is found in hubnet message tag For example if you have a button called move left a slider called step size a switch called all in one step and a monitor called Location the tags for these interface elements will be as follows interface element tag move left move left step size step size Note that yo
212. current plot pen grass plot count patches with pcolor green end Note that we use the p1ot command to add the next point to a plot However before doing that we need to tell NetLogo two things First we need to specify what plot we will be using since later our model might have more than one plot and second we need to specify which pen we want to plot with we will be using two pens on this plot The plot command moves the current plot pen to the point that has an X coordinate equal to 1 greater than the previously plotted X coordinate and a Y coordinate equal to the value given in the plot command in the first case the number of turtles and in the second case the number of green patches As the pens move they each draw a line In order for set current plot Totals to work you ll have to add a plot to your model in the Interface tab then edit it so its name is the same name used in the procedures Even one extra space in the name will throw it off it must be exactly the same in both places e Create a plot using the plot icon on the Toolbar and click on an open spot in the Interface e Set its Name to Totals see image below e Set the X axis label to time e Set the Y axis label to total Tutorial 3 Procedures 65 NetLogo 4 1 2 User Manual Name Totals X axis label time Xmin 0 X max 10 Y axis label totals Y min 0 Y max 10 M Autoplot Plot Pens Choose Pen to Edit default HJ Color b
213. d Colors Import Patch Load an image into the patches using RGB colors see the Colors RGB Import Drawing Load an image into the drawing see the import drawing command Edit Oro out or removes the selected text and temporarily saves it to the lipboard Import HubNet Load the interface from another model into the HubNet Client Editor Client Interface Quit Exits NetLogo Exits NetLogo On Macs this item is on the NetLogo menu instead Macs this item is on the NetLogo menu instead fonts the selected text A e the clipboard text where cursor is currently located Delete Deletes selected text selected text Undo last text editing action you performed Redo Redo last undo action you performed Select All Select all the text in the active window Find Finds a word or sequence of characters within the Information or Procedures tabs Find Next Find the next occurrence of the word or sequence you last used Find ith Shift Left Used in the Procedures tab to change the indentation level of code Shift Right Comment Used in the Procedures tab to add or remove semicolons from code Uncomment semicolons are used in NetLogo code to indicate comments ools Snap To Grid hen enabled new widgets stay on a 5 pixel grid so it is easier to line Note this feature is disabled when zoomed in or out Halt Stops all running code including buttons and the command center Warning since the code i
214. d as the basis of a commercial software or hardware product without first obtaining appropriate licenses from Uri Wilensky We make no representations about the suitability of this software for any purpose Itis provided as is without express or implied warranty BehaviorSpace license Copyright 2009 2010 by Uri Wilensky All rights reserved BehaviorSpace is free and open source software You can redistribute it and or modify it under the terms of the GNU Lesser General Public License LGPL as published by the Free Software Foundation either version 3 of the License or at your option any later version A copy of the LGPL is included in the NetLogo distribution See also http www gnu orqg licenses Extension licenses The extensions included with NetLogo are free and open source software The exact copyright and licensing information varies from extension to extension See the README file in each extension directory Copyright and License Information 3 NetLogo 4 1 2 User Manual Third party licenses Scala Some parts of NetLogo are written in the Scala language and use the Scala standard libraries The license for Scala is as follows Copyright c 2002 2008 EPFL Lausanne unless otherwise specified All rights reserved This software was developed by the Programming Methods Laboratory of the Swiss Federal Institute of Technology EPFL Lausanne Switzerland Permission to use copy modify and distribute this software
215. d link value Reports true if value is of the given type false otherwise item item index list item index string On lists reports the value of the item in the given list with the given index On strings reports the character in the given string at the given index Note that the indices begin from 0 not 1 The first item is item 0 the second item is item 1 and so on suppose mylist is 2 4 6 8 10 NetLogo Dictionary NetLogo 4 1 2 User Manual show item 2 mylist gt 6 show item 3 my shoe gt Won jump jump number The turtle moves forward by number units all at once rather than one step at a time as with the forward command If the turtle cannot jump number units because it is not permitted by the current topology the turtle does not move at all See also forward can move L label label ae This is a built in turtle or link variable It may hold a value of any type The turtle or link appears in the view with the given value attached to it as text You can set this variable to add change or remove a turtle or link s label See also label color plabel plabel color Example ask turtles set label who all the turtles now are labeled with their 7 who numbers ask turtles set label all turtles now are not labeled label color label color This is a built in turtle or link variable It holds a number greater than or equal to 0 and less than 140 This num
216. d or last edited Therefore the effects of such commands as set plot x range and set plot pen color are only temporary Ranges and autoplotting The default x and y ranges for a plot are fixed numbers but they can be changed at setup time or as the model runs To change the ranges at any time use set plot x range and set plot y range Or you can let the ranges grow automatically Either way when the plot is cleared the ranges will return to their default values By default all NetLogo plots have the autoplotting feature enabled This means that if the model tries to plot a point which is outside the current displayed range the range of the plot will grow along one or both axes so that the new point is visible In the hope that the ranges won t have to change every time a new point is added when the ranges grow they leave some extra room 25 if growing horizontally 10 if growing vertically If you want to turn off this feature edit the plot and uncheck the Autoplot checkbox At present it is not possible to enable or disable this feature only on one axis it always applies to both axes Programming Guide 121 NetLogo 4 1 2 User Manual Temporary plot pens Most plots can get along with a fixed number of pens But some plots have more complex needs they may need to have the number of pens vary depending on conditions In such cases you can make temporary plot pens from code and then plot with them These pens are ca
217. d pitch When a group of turtles are created using crt 10 for example the heading will be evenly spaced around the 360 degrees as in 2D NetLogo however pitch and roll will always be zero Take a look at the Turtle Movement buttons e Press the left 1 button How does the turtle move Is is the same or different from 2D NetLogo Which of the turtle variables change e Press the pitch down 1 button How does the turtle move Which of the turtle variables change e Press the left 1 button again How does the turtle move ls it different than the last time you pressed the left 1 button 214 Introducing NetLogo 3D NetLogo 4 1 2 User Manual e Take a little time to play with the Turtle Movement buttons watching both how the turtle moves and which of the turtle variables change You probably noticed that often more than one of the turtle variables change for a single turn for this reason we suggest that you use the turtle commands rather than setting the orientation variables directly Step 3 Observer Movement At the bottom of the interface you will see a group of buttons labeled Observer point of view If you have ever used the 3D view in NetLogo 2D or if you have been using the mouse controls in the 3D view through this tutorial you have been moving the Observer Changing the point of view in the 3D is actually moving and changing the orientation of the Observer The Observer has x y and z coordinates j
218. dditional changes 1 If your model already has a global ticks or clock or time variable get rid of it Use the tick command and ticks reporter instead If your model uses fractional increments of time use tick advance instead of tick If you had a monitor for that variable you can get rid of it there s now a tick counter in the toolbar 2 clear all resets the tick counter to zero If you don t use clear a11 in your setup procedure then you may need to add reset ticks to reset the counter to zero 3 If you used no display and display to prevent view updates from happening in the middle of go you can get rid of them 4 If your model needs to update the view without advancing the tick counter examples Party Dice Stalagmite network models with animated layout models with mouse interaction buttons use the display command to force additional view updates so the user can see what is going on Speed slider Previous versions of NetLogo had a speed slider that could be used to make models run slower so you can see what s going on Transition Guide 147 NetLogo 4 1 2 User Manual In NetLogo 4 0 the slider can be used to speed up models as well It does this by updating the view less frequently Updating the view takes time so the fewer updates the faster the model runs The default position of the slider is in the center When you re at the center the slider says normal speed As you move the slider away from the
219. de sliders switches choosers and any global variables in your model Variables can also include max pxcor min pxcor max pycor and min pycor world width world height and random seed These are not strictly speaking variables but BehaviorSpace lets you vary them as if they were Varying the world dimensions lets you explore the effect of world size upon your model Since setting world width and world height does not necessarily define the bounds of the world how they are varied depends on the location of the origin If the origin is centered BehaviorSpace will keep it centered so the values world width or world height must be odd If one of the bounds is at zero that bound will be kept at zero and the other bound will move for example if you start with a world with min pxcor 0 max pxcor 10 and you vary world width like this world width 1 1 44 min pxcor will stay at zero and max pxcor will set to 11 12 and 13 for each of the runs If neither of these conditions are true the origin is not centered nor at the edge of the world you cannot vary world height or world width directly but you should vary max pxcor max pycor min pxcor and min pycor instead 162 BehaviorSpace Guide NetLogo 4 1 2 User Manual Varying random seed lets you repeat runs by using a known seed for the NetLogo random number generator Note that you re also free to use the random seed command in your experiment s setup commands For more information on ra
220. dels often have many settings each of which can take a range of values Together they form what in mathematics is called a parameter space for the model whose dimensions are the number of settings and in which every point is a particular combination of values Running a model with different settings and sometimes even the same ones can lead to drastically different behavior in the system being modeled So how are you to know which particular configuration of values or types of configurations will yield the kind of behavior you are interested in This amounts to the question of where in its huge multi dimension parameter space does your model perform best For example suppose you want speedy synchronization from the agents in the Fireflies model The model has four sliders number cycle length flash length and number flashes that have approximately 2000 100 10 and 3 possible values respectively That means there are 2000 100 10 3 600 000 possible combinations of slider values Trying combinations one at a time is hardly an efficient way to learn which one will evoke the speediest synchronization BehaviorSpace offers you a much better way to solve this problem If you specify a subset of values from the ranges of each slider it will run the model with each possible combination of those values and during each model run record the results In doing so it samples the model s parameter space not exhaustively but enough so tha
221. develop interactive interfaces for exploring model behavior e Have direct access to patches and network data with built in functions Installation The NetLogo Mathematica link requires Mathematica 6 or greater Mathematica 7 works To install the NetLogo Mathematica link e Go to the menu bar in Mathematica e Click on File and select Install e In the Install Mathematica Item dialog e Select Package for Type of item to install e Click Source and select From file e In the file browser go to the location of your NetLogo installation e click on the Mathematica Link subfolder and select NetLogo m e For Install Name enter NetLogo Mathematica Link 205 NetLogo 4 1 2 User Manual You can either install the NetLogo link in your user base directory or in the system wide directory If the NetLogo link is installed in the user base directory other users on the system must also go through the NetLogo Mathematica link installation process to use it This option might be preferable if you do not have permission to modify files outside of your home directory Otherwise you can install NetLogo Mathematica link in the system wide Mathematica base directory Usage This section will very briefly introduce how to use the NetLogo Mathematica Link It will show you how to load the NetLogo Mathematica link package start NetLogo execute commands and retrieve data from NetLogo Loading the package Once the NetLogo Mathematica link is in
222. does not affect the 3D View as you can simply make the 3D View larger by making the window larger The Smooth edges checkbox controls the use of anti aliasing in the 3D view only and only appears when editing from the 3D view It will make the lines appear less jagged but it will slow down the model Tick counter settings control the appearance of the tick counter which is visible or not in the view control strip Turtle patch and link monitors are easily available through the View just control click Macintosh or right click other systems on the turile or patch you want to inspect and choose inspect turile or inspect patch from the popup menu You can also watch follow or ride a turtle by selecting the appropriate item in the turtle sub menu Turile patch and link monitors can also be opened from the Tools menu or by using the inspect command Some NetLogo models let you interact with the turtles and patches with your mouse by clicking and dragging in the View Manipulating the 3D View At the bottom of the window there are buttons to move the observer or change the perspective from which you are looking at the world 80 Interface Guide NetLogo 4 1 2 User Manual Rotate Zoom Move Interact Reset Perspective Full Screen A blue cross appears at the current focus point as you are adjusting these settings The little blue triangle will always point up the positive y axis so you can orient
223. does not apply a braking force as gogo output port off does Therefore the motor will gradually slow down before stopping completely This will have the same effect as gogo output port off on most output devices other than motors The output ports affected by this command are determined by the gogo talk to output ports command The following code will turn on an output port a for 1 second and then stop the motor gradually gogo talk to output ports a gogo output port on wait 1 gogo output port coast gogo output port off gogo output port off Turns off power to the output ports If using motors a braking force is applied The output ports affected by this command are determined by the gogo talk to output ports command gogo output port on 270 NetLogoLab and the GoGo Board Extension NetLogo 4 1 2 User Manual gogo output port on Turns on power to the output ports The output ports affected by this command are determined by the gogo talk to output ports command gogo output port reverse gogo output port reverse Reverses the direction of the output ports The output ports affected by this command are determined by the gogo talk to output ports command gogo output port that this way gogo output port thatway gogo output port thisway Apply power to the output port in a given direction Output ports can be powered in two directions arbitrarily called thisway and thatway The output ports affected
224. dth plot pen interval with the point plotted as the upper or lower if you are plotting a negative number left corner of the bar e 2 point mode the plot pen draws a point at the point plotted Points are not connected 408 NetLogo Dictionary NetLogo 4 1 2 User Manual The default mode for new pens is O line mode set plot x range set plot y range set plot x range m n max set plot y range min max Sets the minimum and maximum values of the x or y axis of the current plot The change is temporary and is not saved with the model When the plot is cleared the ranges will revert to their default values as set in the plot s Edit dialog setxy setxy X y The turtle sets its x coordinate to x and its y coordinate to y Equivalent to set xcor x set ycor y except it happens in one time step instead of two If xor y is outside the world NetLogo will throw a runtime error setxy 0 0 7 turtle moves to the middle of the center patch setxy random xcor random ycor 7 turtle moves to a random point setxy random pxcor random pycor 7 turtle moves to the center of a random patch See also move to shade of shade of color1 color2 Reports true if both colors are shades of one another false otherwise show shade of blue red gt false show shade of blue blue 1 gt Lrue show shade of gray white gt true shape NetLogo Dictionary 409 NetLogo 4 1 2 User Manual shape P This is a built in
225. e hubnet send message string value This prints value in the text area on the client specified by string See also hubnet broadcast message hubnet send override hubnet send override client name agent or set variable name reporter Evaluates reporter for the agent or agentset indicated then sends the values to the client to override the value of variable name only on client name This is used to change the appearance of agents in the client view hence only built in variables that affect the appearance of the agent may be selected For example you can override the color variable of a turtle ask turtles hubnet send override client name self color red In this example assume that there is a turtles own variable client name which is associated with a logged in client and all the turiles are blue This code makes the turtle associated with each client appear red in his or her own view but not on anyone else s or on the server See also hubnet clear overrides hubnet send watch hubnet send watch client name agent Tells the client associated with client name to watch agent See also hubnet send follow hubnet reset perspective hubnet set client interface hubnet set client interface client type client info If client type is COMPUTER client info is an empty list for computer HubNet hubnet set client interface COMPUTER Future versions of HubNet will support other client types Even for Computer HubNet th
226. e procedure every time Instead the user moves the slider to a value and observes what happens in the model 18 Switch Switches are a visual representation for a true false variable The user is asked to set the variable to either on true or off false by flipping the switch a Chooser Choosers let the user choose a value for a global variable from a list of choices presented in a drop down menu Input Input Boxes are global variables that contain strings or numbers The model author chooses what types of values the user can enter Input boxes can be set to check the syntax of a string for commands or reporters Number input Interface Guide 77 NetLogo 4 1 2 User Manual boxes read any type of constant number expression which allows a more open way to express numbers than a slider Color input boxes offer a NetLogo color chooser to the user ES Monitor Monitors display the value of any expression The expression could be a variable a complex expression or a call to a reporter Monitors automatically update several times per second Der Plots are real time graphs of data the model is generating ES Output The output area is a scrolling area of text which can be used to create a log of activity in the model A model may only have one output area a Note Notes lets you add informative text labels to the Interface tab The contents of notes do not change as the model runs The other controls in the Interface Tool
227. e HubNet Guide e General HubNet Information e Coding HubNet Activities Setup Receiving information from clients Sending information to clients e Calculator HubNet Information e Computer HubNet Information How To Make a Client Interface View Updates on the Clients 4 Clicking in the View on Clients Plot Updates on the Clients General HubNet Information The information presented in this section is specifically targeted at those using computer clients however much of the code presented can be reused with small modifications to use calculator clients Coding HubNet Activities Many HubNet Activities will share bits of the same code That is the code that it used to setup the network and the code that is used to receive information from and send information to the clients If you understand this code you should be able to easily make modifications to existing activities and you should have a good start on writing your own activities To get you started we have provided a Template model in HubNet Computer Activities gt Code Examples that contains the most basic components that will be in the majority of HubNet Activities You should be able to use this activity as a starting point for most projects Setup To make a NetLogo model into a HubNet activity you must first initialize the network In most HubNet activities you will use the startup procedure to initialize the network Startup is a special procedure NetLogo will
228. e RasterDataset kernel rows kernel columns kernel key column key row Reports a new raster whose data consists of the given raster convolved with the given kernel A convolution is a mathematical operation that computes each output cell by multiplying elements of a kernel with the cell values surrounding a particular source cell A kernel is a matrix of values with one particular value defined as the key element the value that is centered over the source cell corresponding to the destination cell whose value is being computed The values of the kernel matrix are given as a list which enumerates the elements of the matrix from left to right top to bottom So the elements of a 3 by 3 matrix would be listed in the following order The key element is specified by column and row within the matrix Columns are numbered from left to right beginning with zero Rows are numbered from top to bottom also beginning with zero So for example the kernel for the horizontal Sobel operator which looks like this would be specified as follows let horizontal gradient gis convolve dataset 3 3 1 0 1 2 0 2 1 0 1 1 1 gis apply raster gis apply raster RasterDataset patch variable Copies values from the given raster dataset to the given patch variable resampling the raster as necessary so that its cell boundaries match up with NetLogo patch boundaries This resampling is done as if using resample rather than raster sample for the sake of
229. e The new definition of setup refers to two new procedures To define setup patches add this to setup patches ask patches set pcolor green end The setup patches procedure sets the color of every patch to green to start with A turtle s color variable is color a patch s is pcolor The only part remaining in our new setup that is still undefined is setup turtles e Add this procedure too to setup turtles create turtles 100 ask turtles setxy random xcor random ycor end Did you notice that the new setup turtles procedure has most of the same commands as the old setup procedure e Switch back to the Interface tab e Press the setup button Voila A lush NetLogo landscape complete with turtles and green patches appears 56 Tutorial 3 Procedures NetLogo 4 1 2 User Manual After seeing the new setup procedure work a few times you may find it helpful to read through the procedure definitions again Turtle variables So we have some turtles running around on a landscape but they aren t doing anything with it Let s add some interaction between the turtles and the patches We ll make the turtles eat grass the green patches reproduce and die The grass will gradually grow back after it is eaten We ll need a way of controlling when a turtle reproduces and dies We ll determine that by keeping track of how much energy each turtle has To do that we need to add a new turtle variable You ve
230. e breed as this turtle or link For turtles or links that do not have any particular breed this is the turtles agentset of all turtles or the links agentset of all links respectively You can set this variable to change a turtle or link s breed See also breed directed link breed undirected link breed Example breed cats cat breed dogs dog 7 turtle code if breed cats show meow set breed dogs show woof directed link breed roads road 7 link code if breed roads set color gray breed breed lt breeds gt lt breed gt This keyword like the globals turtles own and patches own keywords can only be used at the beginning of the Procedures tab before any procedure definitions It defines a breed The first input defines the name of the agentset associated with the breed The second input defines the name of a single member of the breed Any turtle of the given breed e is part of the agentset named by the breed name e has its breed built in variable set to that agentset NetLogo Dictionary 327 NetLogo 4 1 2 User Manual Most often the agentset is used in conjunction with ask to give commands to only the turtles of a particular breed breed mice mousel breed frogs frog to setup clear all create mice 50 ask mice set color white create frogs 50 ask frogs set color green show breed of one of mice 7 prints mice show breed of one of frogs 7 prints frogs end
231. e by 100 to get a result in dollars for display If you must use floating point numbers then in some situations you may need to replace a straightforward equality test suchas if x 1 with a test that tolerates slight imprecision for example if abs x 1 lt 0 0001 Also the precision primitive is handy for rounding off numbers for display purposes NetLogo monitors round the numbers they display to a configurable number of decimal places too Random Numbers The random numbers used by NetLogo are what is called pseudo random This is typical in computer programming That means they appear random but are in fact generated by a deterministic process Deterministic means that you get the same results every time if you start with the same random seed We ll explain in a minute what we mean by seed In the context of scientific modeling pseudo random numbers are actually desirable That s because it s important that a scientific experiment be reproducible so anyone can try it themselves and get the same result that you got Since NetLogo uses pseudo random numbers the experiments that you do with it can be reproduced by others Here s how it works NetLogo s random number generator can be started with a certain seed value which can be any integer Once the generator has been seeded with the random seed command it always generates the same sequence of random numbers from then on For example if you run th
232. e gt GREENS boxes are info lt value gt 51 0 lt value gt changed through E nn i lt min gt 0 0 lt min gt the interface as lt inc gt 1 0 lt inc gt lt parameters gt lt event gt o lt event logger org nlogo log Logger CODE code is compiled timestamp 1177341072208 including level INFO command center f ES Oia concer info lt action gt compiled lt action gt procedures tab cscs Ree Talco des slider bounds lt agentType gt 0 lt agentType gt and buttons lt errorMessage gt success lt errorMessage gt lt event gt lt event logger org nlogo log Logger WIDGETS timestamp 1177341058351 a widget is added level INFO WIDGETS or removed from info type slider gt the interface lt name gt lt name gt lt action gt added lt action gt lt event gt BUTTONS a button is info lt event logger org nlogo log Logger BUTTONS pressed or timestamp 1177341053679 level INFO 196 Logging NetLogo 4 1 2 User Manual released type button gt lt name gt show 1 lt name gt lt action gt released lt action gt lt releaseType gt once lt releaseType gt lt event gt lt event logger org nlogo log Logger SPEE timestamp 1177341042202 the speed slider level INFO changes type speed gt lt value gt 0 0 lt value gt lt event gt ED SLIDER lt event logger org nlogo log Logger TURTL timestamp 1177341094342 level I
233. e have relationship primitive as a string whose elements are given in the following order So to use the example matrix above you would write gis have relationship x y T EEx A much more detailed and formal description of the DE 9IM matrix and the associated point set theory can be found in the OpenGIS Simple Features Specification for SQL The objects x and y may be any one of e a VectorDataset in which case the object s spatial representation is the union of all the points lines or polygons the dataset contains e a VectorFeature in which case the object s spatial representation is defined by the point line or polygon the feature contains e A turtle in which case the spatial representation is a point e A link whose spatial representation is a line segment connecting the two points represented by the turiles the link is connecting e A patch whose spatial representation is a rectangular polygon e An agentset whose spatial representation is the union of the representations of all of the agents it contains e A list containing of any of the items listed here including another list The spatial representation of such a list is the union of the spatial representations of its contents gis relationship of gis relationship of x y Reports the Dimensionally Extended Nine Intersection Model DE 9IM matrix that describes the spatial relationship of the two objects The matrix consists of 9 elements each of wh
234. e import pcolors but that only works for importing maps that are images not maps in other formats It is also possible to write NetLogo code that reads GIS data using our file 1 O primitives such as file open FAQ Frequently Asked Questions 309 NetLogo 4 1 2 User Manual My model runs slowly How can speed it up Here s some ways to make it run faster without changing the structure of the code e Use tick based view updates not continuous updates e Decrease the frequency of view updates by pushing the speed slider to the right or turn updates off using the checkbox e If your model is using all available RAM on your computer then installing more RAM should help If your hard drive makes a lot of noise while your model is running you probably need more RAM e Use turtle size 1 1 5 or 2 as the 2D renderings for these sizes are cached by NetLogo This only affects graphics speed in the 2D view not computation speed In many cases though if you want your model to run faster you may need to make some changes to the code Usually the most obvious opportunity for speedup is that you re doing too many computations that involve all the turtles or all the patches Often this can be reduced by reworking the model so that it does less computation per time step The members of the NetLogo Users Group may be able to help with this Unless you are running the exact same strings over and over using run and runresult are much slower tha
235. e meaning of the second input to this command may change See the HubNet Authoring Guide for details NetLogo Dictionary 357 NetLogo 4 1 2 User Manual if if condition commands Reporter must report a boolean true or false value If condition reports true runs commands The reporter may report a different value for different agents so some agents may run commands and others don t if xcor gt O set color blue 7 turtles in the right half of the world 5 turn blue See also ifelse ifelse value ifelse ifelse reporter commands commands2 Reporter must report a boolean true or false value If reporter reports true runs commands If reporter reports false runs commands2 The reporter may report a different value for different agents so some agents may run commands1 while others run commands2 ask patches ifelse pxcor gt 0 set pcolor blue set pcolor red the left half of the world turns red and 5 the right half turns blue See also if ifelse value ifelse value ifelse value reporter reporter1 reporter2 Reporter must report a boolean true or false value If reporter reports true the result is the value of reporter If reporter reports false the result is the value of reporter2 358 NetLogo Dictionary NetLogo 4 1 2 User Manual This can be used when a conditional is needed in the context of a reporter where commands such as ifelse are not allowed as
236. e middle The NetLogo world is a two dimensional world that is made up of turtles patches and an observer The patches create the ground in which the turtles can move around on and the observer is a being that oversee everything that is going on in the world For a detailed description and specifics about this world refer to the NetLogo Programming Guide In the Command Center we have the ability to give the observer a command the turtles a command or the patches a command We choose between these options by using the popup menu located in the bottom left corner of the Command Center You can also use the tab key on your keyboard to cycle through the different options e In the Command Center click on the observer gt in the bottom left corner Command Center Clear observer gt ask patches set pcolor yellow observer gt ask turtles set color brown obser v observer patches links e Choose turtles from the popup menu e Type set color pink and press return e Press the tab key until you see patches gt in the bottom left corner e Type set pcolor white and press return What does the View look like now Do you notice any differences between these two commands and the observer commands from earlier Tutorial 2 Commands 43 NetLogo 4 1 2 User Manual The observer oversees the world and therefore can give a command to the patches or turtles using ask Like in the first exa
237. e movie you can use QuickTime Player a free download from Apple Since the movies are not compressed they can take up a lot of disk space You will probably want to compress your movies with third party software The software may give you a choice of different kinds of compression Some kinds of compression are lossless while others are lossy Lossy means that in order to make the files smaller some of the detail in the movie is lost Depending on the nature of your model you may want to avoid using lossy compression for example if the view contains fine pixel level detail One software package that can compress QuickTime movies on both the Mac and Windows platforms is QuickTime Pro On Macs iMovie works as well PNG compression is a good choice for lossless compression Perspective The 2D and the 3D view show the world from the perspective of the observer By default the observer is looking down on the world from the positive z axis at the origin You can change the perspective of the observer by using the follow ride and watch observer commands and follow me ride me and wat ch me turtle commands When in follow or ride mode the observer moves with the subject agent around the world The difference between follow and ride is only visible in the 3D view In the 3D view the user can change the distance behind the agent using the mouse When the observer is following at zero distance from the agent it is actually riding the agent When the
238. e rate movie set frame rate frame rate Sets the frame rate of the current movie The frame rate is measured in frames per second If you do not explicitly set the frame rate it defaults to 15 frames per second Must be called after movie start but before movie grab view or movie grab interface See also movie status 378 NetLogo Dictionary NetLogo 4 1 2 User Manual movie start movie start filename Creates a new movie filename specifies a new QuickTime file where the movie will be saved so it should end with mov See also movie grab view movie grab interface movie cancel movie status movie set frame rate movie close movie status movie status Reports a string describing the current movie print movie status gt No movie movie start print movie status gt 0 frames frame rate 15 movie grab view print movie status 1 frames frame rate 15 size 315x315 my lt breeds gt my links my lt breeds gt my links Reports an agentset of all undirected links connected to the caller crt 5 ask turtle 0 create links with other turtles show my links prints the agentset containing all links since all the links we created were with turtle 0 ask turtle 1 show my links shows an agentset containing the link 0 1 end my in lt breeds gt my in links NetLogo Dictionary 379 NetLogo 4 1 2 User Manual my in lt breeds gt my in links Repor
239. e then run one at a time in random order cre 100 fa 10 makes a randomly spaced circle breed canaries canary breed snakes snake to setup clear all create canaries 50 set color yellow create snakes 50 set color green end See also hatch sprout 334 NetLogo Dictionary NetLogo 4 1 2 User Manual create temporary plot pen create temporary plot pen string A new temporary plot pen with the given name is created in the current plot and set to be the current pen Few models will want to use this primitive because all temporary pens disappear when clear plot or clear all plots are called The normal way to make a pen is to make a permanent pen in the plot s Edit dialog If a temporary pen with that name already exists in the current plot no new pen is created and the existing pen is set to the the current pen If a permanent pen with that name already exists in the current plot you get a runtime error The new temporary plot pen has the following initial settings e Pen down e Color black e Mode 0 line mode e Interval 1 See clear plot clear all plots and set current plot pen D date and time date and time Reports a string containing the current date and time The format is shown below All fields are fixed width so they are always at the same locations in the string The potential resolution of the clock is milliseconds Whether you get resolution that high in practice may vary from s
240. e z axis the roll will never change See also setxyz face and zoom oxcor oycor ozcor oxcor oycor ozcor w Reports the x y or z coordinate of the observer See also setxyz P patch patch pxcor pycor pzcor 3D version of patch Given three integers reports the single patch with the given pxcor pycor and pzcor pxcor pycor and pzcor must be integers ask patch 3 4 2 set pcolor green 7 patch with pxcor of 3 and pycor of 4 and pzcor of 2 turns green See also patch Introducing NetLogo 3D 221 NetLogo 4 1 2 User Manual patch at patch at dx dy dz A Ed 3D version of patch at Reports the single patch at dx dy dz from the caller that is dx patches east dy patches north and dz patches up from the caller ask patch at 1 1 1 set pcolor green 5 turns the patch just southeast and up from the caller green patch at heading pitch and distance patch at heading pitch and distance heading pitch distance 3D version of patch at heading and distance patch at heading pitch and distance reports the single patch that is the given distance from this turtle or patch along the given absolute heading and pitch In contrast to patch left and ahead and patch right and ahead this turtle s current heading is not taken into account ask patch at heading pitch and distance 0 90 1 set pcolor green 7 turns the patch directly above the caller green pitch pitch This is a built in tur
241. eCtOrs nhen a ei ahr ain inden ainda 249 IMAL dO Las cde to duo sei cuenta do ad dete hues aia ices a 249 mairix rank cee ec eects EED E dna Sead hte te Ro a ie ocean Uk etek aed PR aah Cde 249 mark CONG a iiss Ooi hae haha bce praia US Sa ARS qe det O e SEE SS dela 249 MALIK AACE ss cosas sta rd Butch led nao O ES ON 249 Advanced features elas ss Murta sett cee dome ea ca aaa 249 MA A EAR ado OIA E do DD O a ee 250 Matrix torecast linGar Growi iran siiaas iria pacadiica bebendo A ad ca nara 250 matrixforecast COMPOUIAd Ar OM Aia 250 Matrix forecast COMTAUOUS QhOWIN cta 2 nrnna nnne 251 MATIX OQESS on cence E E E E E desceanneatageagededgaiasdaas 252 GROOMS a to Lola eM aah oes 253 Sound EXtenSiON iii ii 255 Using the Sound EXLONSION a ida a 255 MIDI SUpport nnr rada dada aa 255 PAVE estica A AA A A AA 255 SOUMOIGNUMIS Sides dec E RE ERR od id 255 sound instrumenis a e a a ae riea er tarte aerea PAESANA 256 SOUNO AYUDO id 256 SOUNO PA MOOD AAA AA dna aa 256 sou undplay note latef eni eo a nE creer 256 sound play sound rare rre 256 SOUNd play SOUN0O ANd Walheoicoccinncnncccncccnccnncnnncnnnc rre 256 SoUNd pPl y SOUNO lt A ao 257 souna Stari nole ta a il ida 257 sound stop note cnn nr nr rr 257 sound stop instrument corn n rn rr rre 257 SOUNO STOP MUS Cid AA A A a da caraio 258 SOUNALNAMES cat tt a dais o le aaa 258 DEUMS ue a A ro Ad A ae 258 PAES AAT IMEA SEAE A EE EA E
242. ecify a different encoding than us ascii such as UTF 8 but NetLogo doesn t support non ASCII characters in most situations so specifying a different encoding may be pointless Controlling API If BehaviorSpace is not sufficient for your needs a possible alternative is to use our Controlling API which lets you write Java code that controls NetLogo The API lets you run BehaviorSpace BehaviorSpace Guide 169 NetLogo 4 1 2 User Manual experiments from Java code or you can write custom code that controls NetLogo more directly to do BehaviorSpace like things See the Controlling section of the User Manual for further details on both possibilities Source code BehaviorSpace is free and open source software It is made available under the GNU Lesser General Public License LGPL version 3 or later The source code is included in the NetLogo distribution in 1ib BehaviorSpace src zip BehaviorSpace is written in the Scala programming language Scala code compiles to Java byte code and is fully interoperable with Java and other JVM languages The sources jar includes instructions on how to recompile it 170 BehaviorSpace Guide System Dynamics Guide This guide has three parts e What is the System Dynamics Modeler A general description of the tool including the ideas and principles behind it e How It Works Describes the interface and how you use it e Tutorial Wolf Sheep Predation aggregate Walks you through creating
243. ed e One or more JAR files which the extension requires e A lib directory with any required native libraries e A src directory containing the source code for the model e Documentation To build your extension you must include NetLogo jar in your class path Examples Several sample extensions with full Java or Scala source code are included with NetLogo Some 230 Extensions Guide NetLogo 4 1 2 User Manual others are available for download here Tutorial Let s write an extension that provides a single reporter called first n integers first n integers will take a single numeric input n and report a list of the integers O through n 1 Of course you could easily do this just in NetLogo it s only an example 1 Create extension folder Since an extension is a folder with several items we first need to create our folder In this example itis called example We will be doing all of our work in that folder We will also want to create a src sub folder to hold our Java code and a classes sub folder for the compiled classes 2 Write primitives The primitives are implemented as one or more Java classes The java files for these classes should be put in the src sub folder A command performs an action a reporter reports a value To create a new command or reporter create a class that implements the interface org nlogo api Command or org nlogo api Reporter which extend org nlogo api Primitive In most cases you can
244. ed ask turtle 0 create links with other turtles show count links shows 4 7 this does nothing since the link already exists ask turtle 0 create link with turtle 1 NetLogo Dictionary 333 NetLogo 4 1 2 User Manual show count links shows 4 since the previous link already existed ask turtle 2 create link with turtle 1 show count links shows 5 end directed link breed red links red link undirected link breed blue links blue link to setup ert 5 create links in both directions between turtle 0 and all other turtles ask turtle 0 create red links to turtles ask turtle 0 create red links from turtles show count links shows 8 j now create undirected links between turtle 0 and other turtles ask turtle 0 create blue links with turtles show count links shows 12 end create turtles crt create lt breeds gt create turtles number create turtles number commands create lt breeds gt number create lt breeds gt number commands Creates number new turtles at the origin New turtles have random integer headings and the color is randomly selected from the 14 primary colors If the create lt breeds gt form is used the new turtles are created as members of the given breed If commands are supplied the new turtles immediately run them This is useful for giving the new turtles a different color heading or whatever The new turtles are created all at onc
245. ed breeds and the commands create lt breed gt to create lt breeds gt to create lt breed gt from and create lt breeds gt from for directed links There cannot be more than one undirected link of the same breed or two unbreeded links between a pair of agents nor more than one directed link of the same breed in the same direction between a pair of agents You can have two directed links of the same breed or two unbreeded links between a pair if they are in opposite directions Layouts As part of our network support we have also added several different primitives that will help you to visualize the networks The simplest is Layout circle which evenly spaces the agents around the center of the world given a radius layout radial is a good layout if you have something like a tree structure though even if there are some cycles in the tree it will still work though as there are more and more cycles it will probably not look as good layout radial takes a root agent to be the central node places it at 0 0 and arranges the nodes connected to it in a concentric pattern Nodes one degree away from the root will be arranged in a circular pattern around the central node and the next level around those nodes and so on layout radial will attempt to account for asymmetrical graphs and give more space to branches that are wider layout radial also takes a breed as an input so you use one breed of links to layout the n
246. edly running a given reporter You can make a list of the same value repeated or all the numbers in a range or a lot of random numbers or many other possibilities See dictionary entry for details and examples The of primitive lets you construct a list from an agentset It reports a list containing each agent s value for the given reporter The reporter could be a simple variable name or a more complex expression even a call to a procedure defined using to report A common idiom is max of turtles sum of turtles and so on You can combine two or more lists using the sentence reporter which concatenates lists by combining their contents into a single larger list Like List sentence normally takes two inputs but can accept any number of inputs if the call is surrounded by parentheses Changing list items 108 Programming Guide NetLogo 4 1 2 User Manual Technically lists can t be modified but you can construct new lists based on old lists If you want the new list to replace the old list use set For example set mylist 2 7 5 Bob 3 0 2 mylist is now 2 7 5 Bob 3 0 2 set mylist replace item 2 mylist 10 mylist is now 2 7 10 Bob 3 0 2 The replace item reporter takes three inputs The first input specifies which item in the list is to be changed O means the first item 1 means the second item and so forth To add an item say 42 to the end of a list use the 1put reporter fput adds an item
247. educe reduce reporter list Reduces a list from left to right using reporter resulting in a single value This means for example that reduce 21 22 1 2 3 4 is equivalent to 1 2 3 4 If list has a single item that item is reported Itis an error to reduce an empty list In reporter use 21 and 22 to refer to the two objects being combined Since it can be difficult to develop an intuition about what reduce does here are some simple examples which while not useful in themselves may give you a better understanding of this primitive show reduce 21 22 1 2 3 gt 6 show reduce 21 22 1 2 3 gt 4 show reduce 2 21 1 2 3 gt 2 show reduce 1 1 2 3 gt 1 show reduce 2 1 2 3 gt 3 398 NetLogo Dictionary NetLogo 4 1 2 User Manual show reduc sentence 21 2 1 2 3 41 5 gt 1 2 3 4 5 show reduce fput 2 21 fput 1 2 3 4 5 gt 54 3 2 1 Here are some more useful examples 7 find the longest string in a list to report longest string strings report reduce ifelse valu length 1 gt length 2 21 2 strings end show longest string hi there gt there count the number of occurrences of an item in a list to report occurrences x the list report reduce ifelse value 22 x 21 1 1 fput 0 the list end show occurrences 1 1 21312311451 gt 6 7 evaluate the polynomial with given c
248. edures A procedure combines a series of NetLogo commands into a single new command that you define You will now learn to write procedures that make turtles move eat reproduce and die You will also learn how to make monitors sliders and plots The model we ll build is a simple ecosystem model not unlike parts of Wolf Sheep Predation from Tutorial 1 Making the setup button To start a new model select New from the File menu Then begin by creating a setup button e Click the Button icon in the toolbar at the top of the Interface tab e Click wherever you want the button to appear in the empty white area of the Interface tab e A dialog box for editing the button opens Type setup in the box labeled Commands e Press the OK button when you re done the dialog box closes Now you have a setup button Pressing the button runs a procedure called setup A procedure is a sequence of NetLogo commands that we assign a new name We haven t defined that procedure yet we will soon Because the button refers to a procedure that doesn t exist yet the button turns red Tutorial 3 Procedures 51 NetLogo 4 1 2 User Manual Interface Information Procedures P 3 M view updates abe Button M L continuous ry Edit Delete Add normal speed a a a Wa 4 ticks 0 Ea If you want to see the actual error message click the button Now we ll create the setup procedure so the error message wi
249. eeeeeaaaaeneeeeeeseseaeaaaaeeeeeeseseanenaaes 211 gogo output port that this way eres ees area arara resareaanens 211 gogo talk to output ports rear ear rr rre 211 GOOG PINO car dacs A A O AEE EP Arara esa 212 DONOSO Oi 272 QOg0 Set bUrst MOde iii ide 272 QOQO Set OUtDUt DOrt DOWEL eee cece cece cece eee e ee eee atten teres ee seas dean ee eeee eee ea aa aaa eeeeeeeeeaeaaaaes 273 QOQO StOD DUTSEMONDEO coccccccnccnncconccononenonenenenenenenenenenennnnrnnr rr rr 273 Profiler EXTENSION ia canada sadia cine deni audi 215 CAINE sarta ca a da 275 E O Eo a a cite 275 EXAM ple SE E E A T E EE EA 275 PRIMIIVES runninn a A A i Sat eae tae Be eat 275 profilercallS e trees a E 275 Profiler exClUSIVE tiME ccceccseeescceeeeeeeeeeseeeeeeceeeeecseceaaaeeeeeeeessseeaeeeeeeeeseessnsnseeeeeeess 276 Profeco 276 A so dito aii io a e Pp 276 PLE IN Jal 6 o OPA PORRES RE e IA DS RR RR DSR O AAA Dv aussie ea REY 276 SPO SS OM as ea ae da cues nc Fe tage caus E E a a 276 DOMO TO oa 276 xi NetLogo 4 1 2 User Manual Table of Contents ARS A O ais dees A E HOW LO USC ii a a a a aa congue A bawdy ada ation ads KNOWN ISSUES ias GAS PENEDO deceo Coordinate System Primitives caia seia desenhada dd as Dataset Primitive S ci ii A ao VectorDalaset Primitives ic ia a in id RasterDataset PriMitiVOS cccooccccnccnonococonccnonacinoncnnnnacnonanoco errar aerea anna naar ran arena Drawing Primitives connacionales
250. elopes or bounding rectangles of all of your datasets in GIS space and map that directly to the bounds of the NetLogo world See GIS General Examples for an example of this technique You may also optionally define a projection for the GIS space in which case datasets will be re projected to match that projection as they are loaded as long as each of your data files has an associated prj file that describes the projection or geographic coordinate system of the data If no associated prj file is found the extension will assume that the dataset already uses the current projection regardless of what that projection is Once the coordinate system is defined you can load datasets using the gis load dataset primitive This primitive reports either a VectorDataset or a RasterDataset depending on what type of file you pass it A VectorDataset consists of a collection of VectorFeatures each one of which is a point line or polygon along with a set of property values A single VectorDataset may contain only one of the three possible types of features There are several things you can do with a VectorDataset ask it for the names of the properties of its features ask it for its envelope bounding rectangle ask for a list of all VectorFeatures in the dataset search for a single VectorFeature or list of VectorFeatures whose value for a particular property is less than or greater than a particular value or lies within a given range or matches a
251. els Library may help as well The NetLogo Users Group is a useful resource How does the NetLogo language differ from other Logos This is answered in detail at the end of the Programming Guide in the User Manual How come my model from an earlier NetLogo doesn t work right See the Transition Guide section of the User Manual for help Why does my code have strange characters in it NetLogo only works in en locales A locale is a setting which tells NetLogo which language you are using as well as how to display dates and numbers You may need to switch to to an English locale before launching NetLogo This is usually done in the Regional Settings or Internationalization panel of the operating system In a future version of NetLogo we plan to support different languages and locales How do take the negative of a number Any of these ways x orl AUR O x With the first way the parentheses are required My turtle moved forward 1 but it s still on the same patch Why If you have disabled wrapping at the world edges in your model then the turtle might be at a world edge and unable to move any further You can test for this using can move Assuming the turtle isn t hitting a world edge moving forward 1 is only guaranteed to take a turtle to a new patch if the turtle s heading is a multiple of 90 that is exactly north south east or west It s because the turtle might not be standing in the center of a patc
252. ensing which are more sturdy and reliable than generic sensors but are also much more expensive As a comparison a proprietary temperature sensor could cost as much as US 50 00 Actuators follow the same rule for example a generic geared motor could cost from US 3 to 10 while a proprietary version would retail for US 30 or 40 Sensors and actuators can be found through online retailers such as Digikey Mouser Phidgets Spark Fun and Solarbotics More information about how to make sensors is available from the How to Make Sensors web page on the GoGo board web site NetLogo models To make use of the GoGo Board extension and the NetLogoLab framework users need to create NetLogo models using the special primitives made available by the extension Later in this document we will provide examples of models that do this How to get a GoGo Board The GoGo Board is not a commercial product and thus cannot be bought at stores To get a GoGo Board you have to build one yourself or ask someone to do it for you Many companies can assemble boards but they normally require a minimum quantity which can range from 5 to 50 The board was especially designed to be easy and cheap to build even if you don t have electronics skills The main resource about the GoGo Board is the web site www gogoboard org where you will find step by step instructions on how to buy components design the printed circuit board and assemble it The GoGo Board mailin
253. ension in your model add this line to the top of your procedures tab extensions gogo If your model already uses other extensions then it already has an extensions line in it so just add gogo to the list After loading the extension see what ports are available by typing the following into the command center print gogo ports You can open the serial port that the GoGo Board is connected to so that commands can begin to be sent to the board by using the gogo open command To make sure the board is properly connected check that it is responding with the ping reporter Note that in order to communicate with the board you need to know which communications port it is connected to If you are not sure which port is being used you can use the gogo ports primitive see below or you can find out by using the Device Manager on a Windows computer in the Control Panel click on the System icon or the System Profiler on Macintosh OS X On Windows gogo open COMI print gogo ping On Linux gogo open dev ttyS01 print gogo ping On Mac gogo open dev tty KeySeriall print gogo ping For more information on NetLogo extensions see the Extensions Guide Models saved as applets using Save as Applet from the File menu cannot use the GoGo extension Applets cannot use extensions that require additional libraries nor can they access external devices For examples that use the GoGo extension see the Robotics NetLogoLab
254. entset gt Because all operations on agentsets are in random order the resulting list is in random order To convert a list of agents to an agentset use the turtle set patch set or link set primitives How do stop foreach To stop a foreach from executing you need to define a separate procedure that contains only the foreach for example to test foreach if print end 1 2 2 3 stop This code will only print the number 1 The stop returns from the current procedure so nothing after the foreach will be executed either If the procedure is a reporter procedure use report instead of stop BehaviorSpace 314 FAQ Frequently Asked Questions NetLogo 4 1 2 User Manual Why are the rows in my BehaviorSpace table results out of order This is normal when doing multiple runs in parallel For a discussion of the issue see the section on parallel runs in the BehaviorSpace Guide section of the User Manual How do measure runs every n ticks Use repeat in your experiment s go commands e g repeat 10 go to measure the run after every 10 ticks Essentially you are making one experiment step equal 10 ticks I m varying a global variable declared in the Procedures tab but it doesn t work Why It s probably because your setup commands or setup procedure are using clear al1 causing the values set by BehaviorSpace to be cleared One possible workaround is to change your experiment s setup co
255. er Variable To create a Variable press the Variable button and click on the diagram Each Variable in the System Dynamics Model requires a unique name which becomes the name of a procedure or a global variable Variables also require an Expression This expression can be a number a variable a complex NetLogo expression or a call to a NetLogo reporter Flow To create a Flow press the Flow button Click and hold where you want the Flow to begin either on a Stock or in an empty area and drag the mouse to where you want the Flow to end on a Stock or in an empty area Each Flow requires a unique name which becomes a NetLogo reporter Flows require an Expression which is the rate of flow from the input to the output This expression can be a number a variable a complex NetLogo expression or a call to a NetLogo reporter If the value is negative the flow is in the opposite direction When more than one Flow is connected to a Stock it is important to consider how they should interact with one another NetLogo will not enforce that the Flows out of a stock occur in any particular order Also NetLogo will not ensure that the sum of Flows out of a Stock are less than or equal to the value of the Stock These behaviors can be implemented explicitly when creating the Expression for a Flow For example if the Flow is defined as a constant value 10 you can ensure it never draws more than the value of the Stock by using the min primitive
256. er 2005 e 3D view for 2D models e System Dynamics Modeler e follow ride and wat ch commands for tracking particular agents e drawing layer for marks left by turtles e GoGo extension for robotics and devices e buttons take turns now instead of interleaving their code with each other Version 2 1 December 2004 e headless mode for command line operation e action keys let buttons be triggered by keypresses e makes QuickTime movies of models e add output area to models e new primitives including let and carefully Version 2 0 2 August 2004 e extensions API for writing commands and reporters in Java e controlling API for controlling NetLogo from external Java code e sound extension for making sounds and music Version 2 0 December 2003 e full support for Mac OS X and Linux e Windows 95 MacOS 8 9 no longer supported e fast flicker free non grid based graphics e strict math mode for identical results cross platform Version 1 3 June 2003 e view control strip e choosers e new primitives including run runresult map foreach filter reduce e some primitives accept a variable number of inputs What s New 19 NetLogo 4 1 2 User Manual Version 1 2 March 2003 e computer HubNet Version 1 1 July 2002 e Save as Applet e printer support e Procedures menu e scrollable Interface tab Version 1 0 April 2002 e initial release after a series of betas 20 What s New System
257. er Manual interface Information 2 Y j M indent automatically Find Check 3 Sheep and wolves are both breeds of turtle breed sheep a sheep sheep is its own plural so we use a sheep as the singular breed wolves wolf turtles own energy both wolves and sheep have energy patches own countdown to setup clear all ask patches set pcolor green 3 check GRASS switch 33 f it is true then grass grows and the sheep eat it 33 if it false then the sheep don t need to eat if grass ask patches set countdown random grass regrowth time initialize grass grow clocks randomly set pcolor one of green brown J set default shape sheep sheep create sheep initial number sheep create the sheep then initialize their variables L set color white set size 1 5 easier to see set label color blue 2 set energy random 2 sheep gain from food setxy random xcor random ycor To determine if the code has any errors you may press the Check button If there are any syntax errors the Procedures tab will turn red and the code that contains the error will be highlighted and a comment will appear in the top box Switching tabs also causes the code to be checked and any errors will be shown so if you switch tabs pressing the Check button first isn t necessary Interface Guide 89 NetLogo 4 1 2 User Manual 2 Y M indent automatically Find Check create wolves initial n
258. er Manual end to check death ask turtles if energy lt 0 die end Lo Esgrow grass ask patches if random 100 lt 3 set pcolor green end Each of these procedures uses the i command Each turtle when it runs check death it will check to see if its energy is less or equal to O If this is true then the turtle is told to die die is a NetLogo primitive When each turtle runs reproduce it checks the value of the turtle s energy variable If it is greater than 50 then the turtle runs the commands inside the first set of brackets In this case it decreases the turtle s energy by 50 then hatches a new turtle with an energy of 50 The hatch command is a NetLogo primitive which looks like this hat ch number commands This turtle creates number new turtles each identical to its parent and asks the new turtle s that have been hatched to run commands You can use the commands to give the new turtles different colors headings or whatever In our case we run one command We set the energy for the newly hatched turtle to be 50 When each patch runs regrow grass it will check to see if a random integer from 0 to 99 is less than 3 If so the patch color is set to green This will happen 3 of the time on average for each patch since there are three numbers 0 1 and 2 out of 100 possible that are less than 3 e Switch to the Interface tab now and press the setup and go buttons You should see
259. er can choose the type of events logged through a configuration file NetLogo uses the Log4j package for logging If you have previous experience with this package you ll find logging in NetLogo familiar Logging is only supported in the special NetLogo Logging application it doesn t work in applets Starting logging This depends on what operating system you are using Mac OS X or Windows There is a special logging launcher in the NetLogo directory called NetLogo Logging Double click on the icon On Windows the NetLogo directory can be found at c Program Files unless you chose a different location when you installed NetLogo Linux and others To enable logging invoke the net logo sh script as follows netlogo sh logging netlogo_logging xml You could also modify the script to include these flags or copy the script and modify the copy You can replace netlogo_logging xml with any valid log4j xml configuration file which will be discussed in more detail later Using logging When NetLogo starts up it will ask for a user name This name will appear in all the logs generated during this session Where logs are stored Logs are stored in the OS specific temp directory On most Unix like systems that is tmp On Windows XP logs can be found in c Documents and Settings lt user gt Local Settings Temp where lt user gt is the logged in user and on Windows Vista the logs can be found inc Users lt user gt AppData Lo
260. ere in the same model You can also use lt link breeds gt own to declare variables of each link breed separately You can change the breed of links like turtles however you cannot the breed of links to be unbreeded links to prevent having breeded and unbreeded links in the same world ask one of friendships set breed streets ask one of friendships set breed links produces a runtime error set default shape may also be used with link breeds to associate it with a particular link shape Code Example Link Breeds Example Buttons Buttons in the interface tab provide an easy way to control the model Typically a model will have at least a setup button to set up the initial state of the world and a go button to make the model run continuously Some models will have additional buttons that perform other actions A button contains some NetLogo code That code is run when you press the button A button may be either a once button or a forever button You can control this by editing the button and checking or unchecking the Forever checkbox Once buttons run their code once then stop and pop back up Forever buttons keep running their code over and over again until either the code hits the stop command or you press the button again to stop it If you stop the button the code doesn t get interrupted The button waits until the code has finished then pops up Normally a button is labeled with the code that it runs
261. ere links stored in agent variables weren t imported correctly fixed bug in run and runresult primitives where running the same string from different procedures could cause a Java exception 4 fixed bug where in some situations zero wasn t always considered equal to itself e g in the remove duplicates primitive 4 fixed bug affecting 3D models where layout circle and tie could cause a Java exception What s New 15 NetLogo 4 1 2 User Manual fixed bug where the NetLogo window tended to jump between monitors on multiple monitor systems fixed bug in text editing where a single edit sometimes required multiple Undo actions to undo 4 fixed bug where export interface didn t always work properly on Windows and Linux fixed bug where extensions that use native libraries e g GoGo could not be reloaded e HubNet the HubNet client is now available as a Java applet which can be embedded in web pages so users can participate in an activity without installing NetLogo new feature support for individualized client views via 0 client overrides hubnet send override 0 client perspectives hubnet send watch hubnet send follow new commands hubnet send message hubnet broadcast message hubnet send clear output and hubnet broadcast clear output new event type mouse up events are now sent 4 fixed longstanding performance issue that was causing activities to use excessive amounts of bandwidth especially activities with many monitors as
262. ere the three items are the x y and z offsets If the caller is the observer then the points are measured relative to the origin in other words the points are taken as absolute patch coordinates If the caller is a turtle the points are measured relative to the turtle s exact location and not from the center of the patch under the turtle ask turtles at points 2 4 0 1 2 1 10 15 10 fd 1 7 only the turtles on the patches at the distances 2 4 0 1 2 1 and 10 15 10 relative to the caller mov D distancexyz distancexyz nowrap distancexyz xcor ycor zcor distancexyz nowrap xcor ycor zcor 3D versions of distancexy Reports the distance from this agent to the point xcor ycor zcor The distance from a patch is measured from the center of the patch distancexyz nowrap always reports the in world distance never a distance that would require wrapping around the edges of the world With distancexyz the wrapped distance around the edges of the world is used if that distance is shorter than the in world distance if distancexyz 0 0 0 lt 10 set color green all turtles less than 10 units from 218 Introducing NetLogo 3D NetLogo 4 1 2 User Manual 7 the center of the screen turn green dz dz x Reports the z increment the amount by which the turtle s zcor would change if the turtle were to take one step forward at its current heading and pitch NOTE dz is simply the sine of t
263. ern edu Reporting Bugs If you would like to report a bug that you find in NetLogo write to bugs ccl northwestern edu When submitting a bug report please try to include as much of the following information as possible e A complete description of the problem and how it occurred e The NetLogo model or code you are having trouble with If possible attach a complete model e Your system information NetLogo version OS version Java version and so on This information is available from NetLogo s About NetLogo menu item then clicking the System tab In saved applets the same information is available by control clicking Mac or right clicking the white background of the applet e Any error messages that were displayed Please copy and paste the entire error message into your email or make a screen capture if you are unable to copy and paste Contacting Us 25 26 NetLogo 4 1 2 User Manual Contacting Us Sample Model Party This activity is designed to get you thinking about computer modeling and how you can use it It also gives you some insight into the NetLogo software We encourage beginning users to start with this activity Ata Party Have you ever been at a party and noticed how people cluster in groups You may have also noticed that people do not stay within one group but move throughout the party As individuals move around the party the groups change If you watched these changes over time you would notice pat
264. ert a model to use a topology you must first decide what settings best describe the world If the answer is not immediately obvious to you based on the real world a room is a box a wire is a cylinder there are a few clues that will help you If anywhere in the code you are checking the bounds of the world or if some patches are not considered neighbors of the patches on the other side of the view it is likely that you are not using a torus If you check bounds in both the x and y directions it s a box in the x direction only a horizontal cylinder the y a vertical cylinder If you use no wrap primitives you are probably not modeling a torus however be careful with this criterion if you use a mix of no wrap and wrap primitives It may be that you were using a no wrap primitive for a visual element but the rest of the NetLogo world is still a torus After you ve determined the topology and changed it by editing the view you may have to make a few small changes to the code If you ve decided that the world is a torus you probably don t have to make any changes at all If your model only uses patch neighbors and diffuse you probably will not need to make many changes If your model has turtles that move around your next step is to determine what happens to them when they reach the edge of the world There are a few common options the turtle is reflected back into the world either systematically or randomly the turtle exits the system dies or t
265. erty value from that VectorFeature is copied directly If more than one VectorFeature covers a percentage of area greater than the threshold only the first will be used e If the total percentage of a patches area covered by VectorFeatures is less than the coverage minimum threshold the target patch variable is set to Not A Number By default the minimum threshold is 10 and the maximum threshold is 33 These values may be modified using the four primitives that follow gis coverage minimum threshold gis coverage minimum threshold Reports the current coverage minimum threshold used by gis apply coverage gis set coverage minimum threshold gis set coverage minimum threshold new threshold Sets the current coverage minimum threshold to be used by gis apply coverage gis coverage maximum threshold gis coverage maximum threshold Reports the current coverage maximum threshold used by gis apply coverage gis set coverage maximum threshold 288 GIS Extension NetLogo 4 1 2 User Manual gis set coverage maximum threshold new threshold Sets the current coverage maximum threshold to be used by gis apply coverage gis intersects gis intersects x y Reports true if the given objects spatial representations share at least one point in common and false otherwise The objects x and y may be any one of e a VectorDataset in which case the object s spatial representation is the union of all the points lines or polygons the dataset contains
266. es of turtles to numbers beyond the edge of the world and NetLogo will wrap the turtle to the other side But in worlds that don t wrap setting the x or y coordinates of a turtle to a point outside the bounds of the world causes a runtime error The world wrap settings were added in NetLogo 3 1 See the Topology section of the Programming Guide for more information To fix your model so that it works regardless of the wrapping settings use one of these two commands instead setxy random xcor random ycor setxy random pxcor random pycor The two commands are a bit different The first command puts the turtle on a random point in the world The second command puts the turtle on the center of a random patch An even more concise way to put a turtle on the center of a random patch is 150 Transition Guide NetLogo 4 1 2 User Manual move to one of patches Transition Guide 151 NetLogo 4 1 2 User Manual 152 Transition Guide Applets NetLogo models can be run as Java applets inside a web browser Making an applet You can make a model into an applet by choosing Save As Applet on NetLogo s File menu If your model has unsaved changes you will first be prompted to save it Then you will also be prompted to save an HTML file containing the applet For applets to work the HTML file your model file ending in nlogo and the file NetLogoLite jar must all be in the same folder You can copy NetLogoLite jar from the folder where you inst
267. es that use the sound extension see the Sound section under Code Examples in the NetLogo Models Library MIDI support The MIDI part simulates a 128 key electronic keyboard with 47 drums and 128 melodic instruments as provided by General MIDI Level 1 specification It supports 15 polyphonic instrument channels and a single percussion channel Using more than 15 different melodic instruments simultaneously in a model will cause some sounds to be lost or cut off The pitch of a melodic instrument is specified by a key number The keys on the keyboard are numbered consecutively from O to 127 where O is the left most key Middle C is key number 60 The loudness of an instrument is specified by a velocity which represents the force with which the keyboard key is depressed Velocity ranges from 0 to 127 where 64 is the standard velocity A higher velocity results in a louder sound Primitives sound drums sound instruments sound play drum sound play note sound play note later sound play sound sound play sound and wait sound play sound later sound start note sound stop note sound stop instrument sound stop music sound drums sound drums Reports a list of the names of the 47 drums for use with sound play drum Sound Extension 255 NetLogo 4 1 2 User Manual sound instruments sound instruments Reports a list of the names of the 128 instruments for use with sound play note sound play note later sound start note and sound st
268. es the run number used in the results files generated by BehaviorSpace Running an experiment When you re done setting up your experiment press the OK button followed by the Run button A dialog titled Run options will appear 164 BehaviorSpace Guide NetLogo 4 1 2 User Manual Run options formats The run options dialog lets you select the formats you would like the data from your experiment saved in Data is collected for each run or step according to the setting of Measure runs at every step option In either case the initial state of the system is recorded after the setup commands run but before the go commands run for the first time Table format lists each interval in a row with each metric in a separate column Table data is written to the output file as each run completes Table format is suitable for automated processing of the data such as importing into a database or a statistics package Spreadsheet format calculates the min mean max and final values for each metric and then lists each interval in a row with each metric in a separate column Spreadsheet data is more human readable than Table data especially if imported into a spreadsheet application Note however that spreadsheet data is not written to the results file until the experiment finishes Since spreadsheet data is stored in memory until the experiment is done very large experiments could run out of memory So you should disable spreadsheet output
269. ese commands random seed 137 show random 100 show random 100 show random 100 You will always get the numbers 79 89 and 61 in that order Note however that you re only guaranteed to get those same numbers if you re using the same version of NetLogo Sometimes when we make a new version of NetLogo the random number generator changes Presently we use a generator known as the Mersenne Twister To create a number suitable for seeding the random number generator use the new seed reporter new seed creates a seed evenly distributed over the space of possible seeds based on the current date and time It never reports the same seed twice in a row 114 Programming Guide NetLogo 4 1 2 User Manual Code Example Random Seed Example If you don t set the random seed yourself NetLogo sets it to a value based on the current date and time There is no way to find out what random seed it chose so if you want your model run to be reproducible you must set the random seed yourself ahead of time The NetLogo primitives with random in their names random random float and so on aren t the only ones that use pseudo random numbers Many other operations also make random choices For example agentsets are always in random order one of and n of choose agents randomly the sprout command creates turtles with random colors and headings and the downhill reporter chooses a random patch when there s a tie All of these random choices are governed
270. et message source and hubnet message tag This will cause an error if there is no new data from the clients 354 NetLogo Dictionary NetLogo 4 1 2 User Manual See the HubNet Authoring Guide for details hubnet message hubnet message Reports the message retrieved by hubnet fetch message See the HubNet Authoring Guide for details hubnet message source hubnet message source Reports the name of the client that sent the message retrieved by hubnet fetch message See the HubNet Authoring Guide for details hubnet message tag hubnet message tag Reports the tag that is associated with the data that was retrieved by hubnet fetch message For Calculator HubNet this will report one of the variable names set with the hubnet set client interface primitive For Computer HubNet this will report one of the Display Names of the interface elements in the client interface See the HubNet Authoring Guide for details hubnet message waiting hubnet message waiting This looks for a new message sent by the clients It reports true if there is one and false if there is not See the HubNet Authoring Guide for details hubnet reset hubnet reset Starts up the HubNet system HubNet must be started to use any of the other hubnet primitives with the exception of hubnet set client interface See the HubNet Authoring Guide for details NetLogo Dictionary 355 NetLogo 4 1 2 User Manual hubnet reset perspective hubnet reset perspective tag
271. etc have lower precedence than reporters with names For example in many Logos if you write sin x 1 itwill be interpreted as sin x 1 NetLogo on the other hand interprets itthe way most other programming languages would and the way the same expression would be interpreted in standard mathematical notation namely as sin x 1 e The and and or reporters are special forms not ordinary functions and they short circuit that is they only evaluate their second input if necessary e Procedures can only be defined in the Procedures tab not interactively in the Command Center Programming Guide 139 NetLogo 4 1 2 User Manual e Reporter procedures that is procedures that report return a value must be defined with to report instead of to The command to report a value from a reporter procedure is report not output e When defining a procedure the inputs to the procedure must be enclosed in square brackets e g to square x e Variable names are always used without any punctuation always foo never foo or foo To make this work instead of a make command taking a quoted argument we supply a set special form which does not evaluate its first input As a result procedures and variables occupy a single shared namespace The last three differences are illustrated in the following procedure definitions most Logos NetLogo to square x to report square x output x x report x x end end Deeper differences
272. etless Bass 37 Slap Bass 1 38 Slap Bass 2 39 Synth Bass 1 40 Synth Bass 2 Strings 41 Violin 42 Viola 43 Cello 44 Contrabass 45 Tremolo Strings 47 Pizzicato Strings 47 Orchestral Harp 48 Timpani Ensemble 49 String Ensemble 1 50 String Ensemble 2 51 Synth Strings 1 52 Synth Strings 2 53 Choir Aahs 54 Voice Oohs 55 Synth Voice 56 Orchestra Hit Brass 57 Trumpet 58 Trombone 59 Tuba 60 Muted Trumpet Sound Extension NetLogo 4 1 2 User Manual 75 Recorder 76 Pan Flute 77 Blown Bottle 78 Shakuhachi 79 Whistle 80 Ocarina Synth Lead 81 Square Wave 82 Sawtooth Wave 83 Calliope 84 Chiff 85 Charang 86 Voice 87 Fifths 88 Bass and Lead Synth Pad 89 New Age 90 Warm 91 Polysynth 92 Choir 93 Bowed 94 Metal 95 Halo 96 Sweep Synth Effects 97 Rain 98 Soundtrack 99 Crystal 100 Atmosphere 101 Brightness 102 Goblins 103 Echoes 104 Sci fi Ethnic 105 Sitar 106 Banjo 107 Shamisen 108 Koto 109 Kalimba 110 Bag pipe 111 Fiddle 12 Shanai Percussive 13 Tinkle Bell 114 Agogo 115 Steel Drums 116 Woodblock 117 Taiko Drum 18 Melodic Tom 119 Synth Drum 120 Reverse Cymbal Sound Effects 121 Guitar Fret Noise 122 Breath Noise 123 Seashore 124 Bird Tweet 259 61 62 63 64 260 French Horn Brass Section Synth Brass 1 Synth Brass 2 NetLogo 4 1 2 User Manual 129 126 12
273. etup button to reset the model 4 Press the go button to start the model running again Challenge As the host of the party you would like to see both men and women mingling within the groups Adjust the tolerance slider on the side of the view to get all groups to be mixed as an end result To make sure all groups of 10 have both sexes at what level should we set the tolerance Test your predictions on the model Can you see any other factors or variables that might affect the male to female ratio within each group Make predictions and test your ideas within this model Feel free to manipulate more than one variable at a time As you are testing your hypotheses you will notice that patterns are emerging from the data For example if you keep the number of people at the party constant but gradually increase the tolerance level more mixed groups appear How high does the tolerance value have to be before you get mixed groups What percent tolerance tends to produce what percentage of mixing Sample Model Party 29 NetLogo 4 1 2 User Manual Thinking With Models Using NetLogo to model situations like this party scenario allows you to experiment with a system in a rapid and flexible way that would be difficult to do in a real world situation Modeling also gives you the opportunity to observe a situation or circumstance with less prejudice as you can examine the underlying dynamics of a situation You may find that as you
274. eturn unlike file print and file show The lack of a carriage return allows you to print several values on the same line This agent is not printed before the value unlike file show Note that this command is the file i o equivalent of type and file open needs to be called before this command can be used See also file print file show and file write file write NetLogo Dictionary 347 NetLogo 4 1 2 User Manual file write value This command will output value which can be a number string list boolean or nobody to an opened file not followed by a carriage return unlike file print and file show This agent is not printed before the value unlike file show Its output also includes quotes around strings and is prepended with a space It will output the value in such a manner that file read will be able to interpret it Note that this command is the file i o equivalent of write and file open needs to be called before this command can be used file open locations txt ask turtles file write xcor file write ycor See also file print file show and file type filter filter reporter list Reports a list containing only those items of list for which the boolean reporter is true in other words the items satisfying the given condition In reporter use to refer to the current item of list show filter lt 3 1 3 2 gt 1 2 show filter first t hi there everyone gt hi
275. eturn allows you to print several values on the same line NetLogo Dictionary 421 NetLogo 4 1 2 User Manual This agent is not printed before the value unlike show type 3 type print 4 gt 3 4 See also print show and write See also output type U undirected link breed undirected link breed lt link breeds gt lt link breed gt This keyword like the globals and breeds keywords can only be used at the beginning of the Procedures tab before any procedure definitions It defines an undirected link breed Links of a particular breed are always either all directed or all undirected The first input defines the name of the agentset associated with the link breed The second input defines the name of a single member of the breed Any link of the given link breed e is part of the agentset named by the link breed name e has its built in variable breed set to that agentset e is directed or undirected as declared by the keyword Most often the agentset is used in conjunction with ask to give commands to only the links of a particular breed undirected link breed streets street undirected link breed highways highway to setup clear all crt 2 ask turtle O create street with turtle 1 ask turtle 0 create highway with turtle 1 end ask turtle 0 show sort my links 7 prints street 0 1 highway 0 1 See also breed directed link breed untie untie Unties end2 from end7 sets tie
276. etwork and not another Programming Guide 133 NetLogo 4 1 2 User Manual Given a set of anchor nodes layout tutte places all the other nodes at the center of mass of the nodes it is linked to The anchor set is automatically arranged in a circle layout with a user defined radius and the other nodes will converge into place this of course means that you may have to run it several times before the layout is stable layout spring and __layout magspring are quite similar and are useful for many kinds of networks The drawback is that they are relatively slow since they take many iterations to converge In both layouts the links act as springs that pull the nodes they connect toward each other and the nodes repel each other In the magnetic spring there is also a magnetic field pulling the nodes in a compass direction you choose The strength of all of these forces are controlled by inputs to the primitives These inputs will always have a value between 0 and 1 keep in mind that very small changes can still affect the appearance of the network The springs also have a length in patch units however because of all the forces involved the nodes will not end up exactly that distance from each other The magnetic spring layout also has a boolean input bidirectional which indicates whether the springs should push in both directions parallel to the magnetic field if it is true the networks will be more evenly spaced 134 Programming Guide Ne
277. exists plot pen down plot pen reset plot pen up plot x max plot x min plot y max plot y min plotxy set current plot set current plot pen set histogram num bars set plot pen color set plot pen interval set plot pen mode set plot x range set plot y range Links both ends clear links create lt breed gt from create lt breeds gt from create lt breed gt to in lt breed gt neighbors in lt breed gt from in link neighbor in link neighbors in link from is directed link is link is link set is undirected link __layout magspring layout radial layout spring layout tutte lt breed gt neighbor lt breed gt neighbors lt breed gt with link heading link length link neighbor link links links own lt link breeds gt own link neighbors link with my lt breeds gt my in lt breeds gt my in links my links my out lt breeds gt my out links no links other end out lt breed gt neighbor out lt breed gt neighbors out lt breed gt to out link neighbor out link neighbors out link to show link tie untie Movie movie cancel movie close movie grab view movie grab interface movie set frame rate movie start movie status BehaviorSpace behaviorspace run number System netlogo applet netlogo version NetLogo Dictionary 319 NetLogo 4 1 2 User Manual Built In Variables Turtles breed color heading hidden label label color pen mode pen size shape size who xcor ycor Patches pcolor plabel plabel color pxcor pycor Links Other k
278. extend the abstract class org nlogo api DefaultReporter or org nlogo api DefaultCommand DefaultReporter requires that we implement Object report Argument args Context context throws ExtensionException Since our reporter takes an argument we also implement Syntax getSyntax Here s the implementation of our reporter in a file called src IntegerList java import org nlogo api public class IntegerList extends DefaultReporter take one number as input report a list public Syntax getSyntax return Syntax reporterSyntax new int Syntax TYPE_NUMBER Syntax TYPE_LIST y public Object report Argument args Context context throws ExtensionException create a NetLogo list for the result LogoList list new LogoList Extensions Guide 231 NetLogo 4 1 2 User Manual ine n 3 use typesafe helper method from org nlogo api Argument to access argument try n args 0 getIntValue catch LogoException e throw new ExtensionException e getMessage if n lt 0 signals a NetLogo runtime error to the modeler throw new ExtensionException input must be positive populate the list note that we use Double objects NetLogo numbers are always doubles for int i 0 i lt n itt list add Double valueOf i return list Notes e The number objects we
279. ey were built in NetLogo primitives Where extensions are located NetLogo will look for extensions in several places 1 In the folder of the current model 2 The extensions folder in the same location as the NetLogo application Each NetLogo extension consists of a folder with the same name as the extension entirely in lower case This folder must contain a JAR file with the same name as the folder For example the sound extension is stored in a folder called sound with a file inside called sound jar For more information about the contents of an extension s folder please see the section of this manual on Writing Extensions To install a NetLogo extension for use by any model put the extension s folder in the extensions directory in the NetLogo directory Or you can just keep the extension s folder in the same folder as the model that uses it Some extensions depend on additional files These files will be in the extension s folder along with the JAR file The folder may also contain other files such as documentation and example models Extensions Guide 229 NetLogo 4 1 2 User Manual Applets Models saved as applets using Save as Applet on NetLogo s File menu can make use of extensions Copy the entire extension directory into the directory that contains the model file Applets can use almost any extension even those that require external jars However applets still cannot use extensions that require native libraries this incl
280. false then condition2 will not be run since it can t affect the result if pxcor gt 0 and pycor gt 0 set pcolor blue the upper right quadrant of 7 patches turn blue any any agentset Reports true if the given agentset is non empty false otherwise Equivalent to count agentset gt 0 but more efficient and arguably more readable 1f any turtles with color red show at least one turtle is red Note nobody is not an agentset You only get nobody back in situations where you were expecting a single agent not a whole agentset If any gets nobody as input an error results See also all nobody approximate hsb approximate hsb hue saturation brightness Reports a number in the range 0 to 140 not including 140 itself that represents the given color specified in the HSB spectrum in NetLogo s color space All three values should be in the range 0 to 255 The color reported may be only an approximation since the NetLogo color space does not include all possible colors It contains only certain discrete hues and for each hue either saturation or brightness may vary but not both at least one of the two is always 255 show approximate hsb 0 0 0 gt 0 black show approximate hsb 127 5 255 255 gt 85 2 cyan See also extract hsb approximate rgb extract rgb 322 NetLogo Dictionary NetLogo 4 1 2 User Manual approximate rgb approximate rgb red green blue Reports a
281. fd 0 3 The jump command always takes exactly one turn regardless of distance To understand the difference between ask and ask concurrent consider the following two commands ask turtles fd 5 ask concurrent turtles fd 5 Programming Guide 135 NetLogo 4 1 2 User Manual With ask the first turtle takes ten steps forward then the second turtle takes ten steps forward and so on With ask concurrent all of the turtles take one step forward Then they all take a second step and so on Thus the latter command is equivalent to repeat 5 ask turtles fd 1 Code Example Ask Concurrent Example shows the difference between ask and ask concurrent The behavior of ask concurrent cannot always be so simply reproduced using ask as in this example Consider this command ask concurrent turtles fd random 10 In order to get the same behavior using ask we would have to write turtles own steps ask turtles set steps random 10 while any turtles with steps gt 0 ask turtles with steps gt 0 fd 1 set steps steps 1 To prolong an agent s turn use the without interruption command The command blocks inside some commands such as create turtles and hat ch have an implied without interruption around them Note that the behavior of ask concurrent is completely deterministic Given the same code and the same initial conditions the same thing will always happen if you are usi
282. for the plot there would be number number of bars drawn if the histogram command is called See also histogram NetLogo Dictionary 407 NetLogo 4 1 2 User Manual set line thickness set line thickness number Specifies the thickness of lines and outlined elements in the turtle s shape The default value is O This always produces lines one pixel thick Non zero values are interpreted as thickness in patches A thickness of 1 for example produces lines which appear one patch thick It s common to use a smaller value such as 0 5 or 0 2 Lines are always at least one pixel thick This command is experimental and may change in later releases set patch size set patch size size gt Sets the size of the patches of the view in pixels The size is typically an integer but may also be a floating point number See also patch size resize world set plot pen color set plot pen color number Sets the color of the current plot pen to number set plot pen interval set plot pen interval number Tells the current plot pen to move a distance of number in the x direction during each use of the plot command The plot pen interval also affects the behavior of the histogram command set plot pen mode set plot pen mode number Sets the mode the current plot pen draws in to number The allowed plot pen modes are e 0 line mode the plot pen draws a line connecting two points together e 1 bar mode the plot pen draws a bar of wi
283. formation see the NetLogo Mathematica Tutorial notebook included with NetLogo The notebook walks you through the process of using the link with many examples along the way If you do not have Mathematica but are considering using the link you can download a PDF of the evaluated tutorial Known Issues e A NetLogo session cannot be quit without exiting J Link the Java Mathematica link entirely This may disrupt other packages that make use of J Link e If a model loaded with the NetLogo Mathematica link uses a NetLogo extension the extension must be located in the same directory as the extension itself If the extension is located in NetLogo s application wide extensions directory it will not be found e Calls to NetLogo such as NLCommand and NLReport cannot be aborted Credits The primary developer of the NetLogo Mathematica link was Eytan Bakshy To refer to this package in academic publications please use Bakshy E Wilensky U 2007 NetLogo Mathematica Link http ccl northwestern edu netlogo mathematica html Center for Connected Learning and Computer Based Modeling Northwestern University Evanston IL Mathematica Link 207 NetLogo 4 1 2 User Manual 208 Mathematica Link Introducing NetLogo 3D NetLogo includes the NetLogo 3D application a preview release that allows you to create 3D worlds Caution NetLogo s support for 3D is experimental Models created with this release may not be compatible with f
284. frame setVisible true comp open models Sample Models Earth Science Fire nlogo comp command comp command comp command setup comp command repeat 50 go println comp report burned trees def wait block gt Unit java awt EventQueue invokeAndWait new Runnable def run block set density 62 random seed 0 The embedding API gives you a variety of model control features in addition to those provided in the App Class you can simulate button presses enable logging create and hide widgets among others See the NetLogo API Specification for details To use the embedded component you must have NetLogo jar in your classpath If you want to use logging you must also have the log4j jar from the lib directory in your classpath Conclusion Don t forget to consult the NetLogo API Specification for full details on these classes and methods Some API facilities exist but are not yet documented So if you don t see the capability you want contact us we may be able to help you do you what you want Please do not hesitate to contact us at feedback ccl northwestern edu with questions as we may be able to find a workaround or provide additional guidance where our documentation is thin 204 Controlling Guide Mathematica Link What is it The NetLogo Mathematica link provides modelers with an easy to use real time link between NetLogo and Mathematica Together these tools can p
285. fsets to a turtle heading in degrees from 0 to 360 Note that this version of atan is designed to conform to the geometry of the NetLogo world where a heading of 0 is straight up 90 is to the right and so on clockwise around the circle Normally in geometry an angle of 0 is right 90 is up and so on counterclockwise around the circle and atan would be defined accordingly When y is 0 if x is positive it reports 90 if x is negative it reports 270 if x is zero you get an error show atan 1 1 gt 135 show atan 1 1 gt 315 autoplot autoplot Reports true if auto plotting is on for the current plot false otherwise auto plot off auto plot on auto plot off auto plot on This pair of commands is used to control the NetLogo feature of auto plotting in the current plot Auto plotting will automatically update the x and y axes of the plot whenever the current pen exceeds these boundaries It is useful when wanting to show all plotted values in the current plot regardless of the current plot ranges B back bk NetLogo Dictionary 325 NetLogo 4 1 2 User Manual back number The turtle moves backward by number steps If number is negative the turtle moves forward Turtles using this primitive can move a maximum of one unit per time increment So bk 0 5 and bk 1 both take one unit of time but bk 3 takes three If the turtle cannot move backward number steps because it is not permitted by the current topo
286. ften means the model progresses faster Note that if you push the speed slider well to the right the view update may update so frequently that the model appears to have slowed down It hasn t as you can see by watching the tick counter Only the frequency of updates has lessened Adjusting Settings Sliders and Switches The settings within a model give you an opportunity to work out different scenarios or hypotheses Altering the settings and then running the model to see how it reacts to those changes can give you a deeper understanding of the phenomena being modeled Switches and sliders give you access to a model s settings Here are the switches and sliders in Wolf Sheep Predation setup go i i Grass settings i Sheep settings Wolf settings Let s experiment with their effect on the behavior of the model Tutorial 1 Models 33 NetLogo 4 1 2 User Manual e Open Wolf Sheep Predation if it s not open already e Press setup and go and let the model run for about a 100 time ticks Note there is a readout of the number of ticks right above the plot e Stop the model by pressing the go button What happened to the sheep over time Let s take a look and see what would happen to the sheep if we change one of the settings e Turn the grass switch on e Press setup and go and let the model run for a similar amount of time as before What did this switch do to the model Was
287. g list is gogoboardOyahoogroups com and you can join it by going to Yahoo groups The GoGo Board wiki can be found at www edudesign org gogowiki NetLogoLab and the GoGo Board Extension 263 NetLogo 4 1 2 User Manual Installing and testing the GoGo Extension The GoGo Board needs to communicate with the computer in some way and to do so it uses the serial port The choice of this port instead of a USB port was motivated by the board s low cost principle the components needed to build a USB compatible board would be more expensive If your computer does not have a serial port you need to purchase a USB to Serial adapter which can be easily found in computer stores with prices ranging from US 15 to US 30 if you have a Mac or Linux machine make sure the adapter is compatible with your platform One brand that normally works quite well for all platforms is Keyspan USA 19HS model although it is one of the most expensive ones If you are using a serial to USB adapter you will need to make sure the drivers are installed before you begin the adapter may come with a CD with the appropriate drivers otherwise you will need to download them from the company s web site Make sure to plug the adapter into the computer and the GoGo board Turn the GoGo board on using the switch behind the power connector The GoGo board will beep and the red light will turn on Windows The GoGo extension requires no special installation on Windows Mac OS X T
288. g only those agents that reported true in other words the agents satisfying the given condition show count patches with pcolor red 7 prints the number of red patches lt breed gt with link with lt breed gt with turtle link with turtle Report the undirected link between turtle and the caller If no link exists then it reports nobody ert 2 ask turtle 0 create link with turtle 1 show link with turtle 1 prints link 0 1 See also in link from out link to with max agentset with max reporter Takes two inputs on the left an agentset usually turtles or patches On the right a reporter Reports a new agentset containing all agents reporting the maximum value of the given reporter show count patches with max pxcor 7 prints the number of patches on the right edge See also max one of max n of with min agentset with min reporter Takes two inputs on the left an agentset usually turtles or patches On the right a reporter Reports a new agentset containing only those agents that have the minimum value of the given reporter show count patches with min pycor NetLogo Dictionary 427 NetLogo 4 1 2 User Manual 7 prints the number of patches on the bottom edge See also min one of min n of with local randomness with local randomness commands The commands are run without affecting subsequent random events This is useful for performing extra operations such as o
289. ge of the world See the Topology section for more information Procedures In NetLogo commands and reporters tell agents what to do A command is an action for an agent to carry out A reporter computes a result and report it Most commands begin with verbs create die jump inspect clear while most reporters are nouns or noun phrases Commands and reporters built into NetLogo are called primitives The NetLogo Dictionary has a complete list of built in commands and reporters Commands and reporters you define yourself are called procedures Each procedure has a name preceded by the keyword to The keyword end marks the end of the commands in the procedure Once you define a procedure you can use it elsewhere in your program Many commands and reporters take inputs values that the command or reporter uses in carrying out its actions Examples Here are two command procedures 94 Programming Guide NetLogo 4 1 2 User Manual to setup clear all clear the world crt ro make 10 new turtles end to go ask turtles fd 1 all turtles move forward one step rt random 10 jj and turn a random amount lt random 10 end Note the use of semicolons to add comments to the program Comments make your program easier to read and understand In this program e setup and go are user defined commands eclear all crt create turtles ask 1t left turn and rt right turn are all primitive co
290. gis envelope and netlogo envelope parameters must each be four element lists consisting of minimum x maximum x minimum y maximum y The scale of the transformation will be equal to the minimum of the scale necessary to make the mapping between the ranges of x values and the scale necessary to make the mapping between the ranges of y values The GIS space will be centered in NetLogo space For example the following two lists would map all of geographic latitude and longitude space in degrees to NetLogo world space regardless of the current dimensions of the NetLogo world list 180 180 90 90 list min pxcor max pxcor min pycor max pycor However if you re setting the envelope of the NetLogo world you should probably be using set world envelope below gis set transformation ds gis set transformation ds gis envelope netlogo envelope Does the same thing as set transformation above except that it allows the scale for mapping the range of x values to be different than the scale for y values The ds on the end stands for different scales Using different scales will cause distortion of the shape of GIS features and so it is generally not recommended but it may be useful for some models Here is an example of the difference between set transformation and set transformation ds Using set transformation the scale Using set transformation ds the along the x and y axis is the same scale along the x axis is stretched
291. gramming Guide for more information Experimenting with commands We suggest you start experimenting with other turtle commands Type commands into the Command Center lke turtles gt set color red or add commands to setup go Of move turtles Note that when you enter commands in the Command Center you must choose turtles gt patches gt or observer gt in the popup menu on the left depending on which agents are going to run the commands It s just like using ask turtles Or ask patches but saves typing You can also use the tab key to switch agent types which you might find more convenient than using the menu Tutorial 3 Procedures 55 NetLogo 4 1 2 User Manual You might try typing turt les gt pen down into the Command Center and then pressing the go button Also inside the move turtles procedure you can try changing right random 360 to right random 45 Play around It s easy and the results are immediate and visible one of NetLogo s many strengths When you feel you ve done enough experimenting for now you re ready to continue improving the model you are building Patches and variables Now we ve got 100 turtles aimlessly moving around completely unaware of anything else around them Let s make things a little more interesting by giving these turtles a nice background against which to move e Go back to the setup procedure We can rewrite it as follows LO Setup clear all setup patches setup turtles end
292. growth matrix forecast continuous growth matrix regress Matrix creation amp conversion to from lists matrix make constant matrix make constant n rows n cols number Reports a new n rows by n cols matrix object with all entries in the matrix containing the same value number matrix make identity 244 Matrix Extension NetLogo 4 1 2 User Manual matrix make identity n size Reports a new square matrix object with dimensions n size x n size consisting of the identity matrix 1s along the main diagonal Os elsewhere matrix from row list matrix from row list nested list Reports a new matrix object created from a NetLogo list where each item in that list is another list corresponding to each of the rows of the matrix print matrix from row list 1 2 3 4 gt matrix 12 3 4 7 Corresponds to this matrix ee ee 5 3 4 matrix from column list matrix from column list nested list Reports a new matrix object created from a NetLogo list containing each of the columns of the matrix matrix to row list matrix to row list matrix Reports a list of lists containing each row of the matrix matrix to column list matrix to column list matrix Reports a list of lists containing each column of the matrix matrix copy matrix copy matrix Reports a new matrix that is an exact copy of the given matrix This primitive is important because the matrix type is mutable changeable Here s a code example
293. gument to specify the name of the setup to use In order to run any of these experiments in 3D add Dorg nlogo is3d true to any of these startup commands for example java server Dorg nlogo is3d true Xmx1024M cp NetLogo jar org nlogo headless Main model Fire3D nlogo N xperiment experimentl N table Note that you should supply a 3D model and there are also 3D arguments max pzcor lt number gt and min pzcor lt number gt The next section has information on how to create standalone experiment setup files using XML 168 BehaviorSpace Guide NetLogo 4 1 2 User Manual Setting up experiments in XML We don t yet have detailed documentation on authoring experiment setups in XML but if you already have some familiarity with XML then the following pointers may be enough to get you started The structure of BehaviorSpace experiment setups in XML is determined by a Document Type Definition DTD file The DTD is stored in NetLogo jar as system behaviorspace dtd JAR files are also zip files so you can extract the DTD from the JAR using Java s jar utility or with any program that understands zip format The easiest way to learn what setups look like in XML though is to author a few of them in BehaviorSpace s GUI save the model and then examine the resulting nlogo file in a text editor The experiment setups are stored towards the end of the nlogo file in a section that begins and ends with a experiments t
294. h 330 NetLogo Dictionary NetLogo 4 1 2 User Manual is displayed when you edit the plot If there are no plot pens after deleting all temporary pens that is to say if there are no permanent plot pens a default plot pen will be created with the following initial settings e Pen down e Color black e Mode O line mode e Name default e Interval 1 See also clear all plots clear turtles ct clear turtles pes Kills all turtles Also resets the who numbering so the next turtle created will be turtle O See also die color color M This is a built in turtle or link variable It holds the color of the turtle or link You can set this variable to make the turtle or link change color Color can be represented either as a NetLogo color a single number or an RGB color a list of 3 numbers See details in the Colors section of the Programming Guide See also pcolor cos cos number Reports the cosine of the given angle Assumes the angle is given in degrees show cos 180 gt 1 NetLogo Dictionary 331 NetLogo 4 1 2 User Manual count count agentset Reports the number of agents in the given agentset show count turtles 7 prints the total number of turtles show count patches with pcolor red 7 prints the total number of red patches create ordered turtles cro create ordered lt breeds gt create ordered turtles number create ordered turtles number commands create ordered lt breeds
295. h It might be near the corner of a patch For example suppose your turtle is close to the southwest corner of a patch and is facing northeast The length of the patch diagonal is 1 414 the square root of two so fd 1 will leave the turtle near the northeast corner of the same patch If you don t want to have to think about these issues one possibility is to write your model in such a way that your turtles always come to rest on patch centers See next question FAQ Frequently Asked Questions 311 NetLogo 4 1 2 User Manual How do keep my turtles on patch centers A turtle is on a patch center when its xcor and ycor are integers You can move a turtle to the center of its current patch with either of these two equivalent commands move to patch here setxy pxcor pycor But you ll never need to do that if you never allow turtles off of patch centers in the first place The sprout command creates turtles on patch centers For example ask n of 50 patches sprout 1 face one of neighbors4 Another way for a turtle to start on a patch center is with a command such as this line of turtle code which moves it to the center of a random patch move to one of patches Once a turtle is on a patch center as long as its heading always stays an exact multiple of 90 that is to say due north east south or west and as it long as it moves forward or back by integer amounis it will always land on patch centers See Random Grid Wa
296. h our diagram by introducing a population of wolves which eat sheep Step 3 Wolf Predation e Move back to the System Dynamics window e Add a stock of wolves e Add Flows Variables and Links to make your diagram look like this sheep birth rate e Add one more Flow from the wolves Stock to the Flow that goes out of the Sheep stock e Fill in the names of the diagram elements so it looks like this 180 System Dynamics Guide NetLogo 4 1 2 User Manual EA Isheep births sheep birth rate predator efficiency wolf death rate where initial value of wolves is 30 wolf deaths iS wolves wolf death rate wolf death rateis 0 15 predator efficiency is 8 wolf births iS wolves predator efficiency predation rate sheep predation rate is 3 0E 4 and sheep deaths iS sheep predation rate wolves Now we re really done e Go back to the main NetLogo window e Add a plot pen named wolves to the population plot e Press setup and go to see your System Dynamics Modeler diagram in action You see a plot of the populations that looks like this System Dynamics Guide 181 NetLogo 4 1 2 User Manual AOS Bl gt 34 More H wolves 467 279 setup sheep 7379 098 populations Pens 182 System Dynamics Guide HubNet Guide This section of the User Manual introduces the HubNet system and includes instructions to set up and run a HubNet ac
297. hange if the model uses random numbers If you want to run the model more than once at each combination of settings enter a higher number Measure runs using these reporters This is where you specify what data you want to collect from each run For example if you wanted to record how the population of turtles rose and fell during each run you would enter count turtles You can enter one reporter or several or none at all If you enter several each reporter must be on a line by itself for example BehaviorSpace Guide 163 NetLogo 4 1 2 User Manual If you don t enter any reporters the runs will still take place This is useful if you want to record the results yourself your own way such as with the export world command Measure runs at every step Normally NetLogo will measure model runs at every step using the reporters you entered in the previous box If you re doing very long model runs you might not want all that data Uncheck this box if you only want to measure each run after it ends Setup commands These commands will be used to begin each model run Typically you will enter the name of a procedure that sets up the model typically setup But it is also possible to include other commands as well Go commands These commands will be run over and over again to advance to the model to the next step Typically this will be the name of a procedure such as go but you may include any commands you like Stop
298. hape to a different shape or having a different default turtle shape for each breed of turtle The shapes primitive reports a list of currently available turtle shapes in the model This is useful if for example you want to assign a random shape to a turtle ask turtles set shape one of shapes Programming Guide 115 NetLogo 4 1 2 User Manual Use the Turtle Shapes Editor to create your own turtle shapes or to add shapes to your model from our shapes library or to transfer shapes between models For more information see the Shapes Editor section of this manual The thickness of the lines used to draw the vector shapes can be controlled by the set line thickness primitive Code Examples Breeds and Shapes Example Shape Animation Example Link Shapes Link Shapes are similar to turtle shapes only you use the Link Shape Editor to create and edit them Link shapes consist of between O and 3 lines which can have different patterns and a direction indicator that is composed of the same elements as turtle shapes Links also have a shape variable that can be set to any link shape that is in the model By default links have the default shape though you can change that using set default shape The link shapes reporter reports all the link shapes included in the current model The thickness of the lines in the link shape is controlled by the thickness link variable Tick Counter In many NetLogo models time passes in dis
299. hapes See the Shapes Editor Guide for more information Editor Link Shapes Editor Draw link shapes See the Shapes Editor Guide for more information BehaviorSpace Runs the model over and over with different settings See the BehaviorSpace Guide for more information System Dynamics Opens the System Dynamics Modeler See the System Dynamics Modeler Modeler Guide for more details MES the HubNet Client Editor See the HubNet Authoring Guide for Editor more details Center information Zoom Larger Increase the overall screen size of the model Useful on large monitors or when using a projector in front of a group Normal Size Reset the screen size of the model to the normal size Smaller Decrease the overall screen size of the model abs his menu offers keyboard shortcuts for each of the tabs On Macs it s Command 1 through Command 3 On Windows it s Control 1 through Control 3 Help About NetLogo Information on the current NetLogo version the user is running On Macs this menu item is on the NetLogo menu instead Dictionar reporter Manual NetLogo Dictionary Opens the NetLogo Dictionary in a web browser Tabs At the top of NetLogo s main window are three tabs labeled Interface Information and Procedures Only one tab at a time can be visible but you can switch between them by clicking on the tabs at the top of the window Interface Guide 75 NetLogo 4 1 2 User Manual
300. hapes have true 3D counterparts a 3D circle is actually a sphere in the 3D view so they are automatically mapped to that shape triangle cone Interface Guide 81 NetLogo 4 1 2 User Manual cylinder 3D cylinder line half 3D line half car 8D car All other shapes are interpreted from their 2D shapes If a shape is a rotatable shape it is assumed to be a top view and it is extruded as if through a cookie cutter and oriented parallel to the xy plane as in Ants If a shape is non rotatable it is assumed to be a side view so it is drawn always facing the observer and with no thickness as in Wolf Sheep Predation Command Center The Command Center allows you to issue commands directly without adding them to the model s procedures Commands are instructions you give to the agents in your model This is useful for inspecting and manipulating agents on the fly Tutorial 2 Commands is an introduction to using commands in the Command Center Let s take a look at the design of the Command Center 82 Interface Guide NetLogo 4 1 2 User Manual Command Center Wi Clear turtles gt set color red patches gt set pcolor white observer gt ask turtle 10 set color blue observer gt ask turtle 1 set color blue observer gt crt 10 pa The smaller box below the large box is where you type a command After typing it press the Return or Enter key to run it To the left of where you t
301. he Observer variables change e Press the facexyz button How does the view change How do the Observer variables change When you setxyz the center of the sphere remains the same so the Observer automatically keeps that point in the center of the view However the radius of the sphere may change as well as the Observer s orientation in relation to the center When you facexyz or face the center of the sphere changes but the Observer does not move The radius of the sphere may change as well as the orientation of the Observer FAQ Frequently Asked Questions e Can make patches or turtles translucent e Can make a 3D applet e Does NetLogo 3D work with my stereoscopic device e Can make custom 3D shapes Can make patches or turtles translucent Not at this time We have tentative plans to make this possible sometime in the future Can make a 3D applet Not at this time We are looking into alternatives to make this possible however it may be quite some time before it is completed 216 Introducing NetLogo 3D NetLogo 4 1 2 User Manual Does NetLogo work with my stereoscopic device NetLogo supports fullscreen exclusive mode If that is all your device needs then possibly yes However it can be tricky to get it working We don t have any such devices so it is difficult for us to make the process easier lf your device needs something else for example quadbuffers enabled the answer is probably no Can
302. he leaf turtle is unchanged The tie mode of a link can be set to fixed using the tie command and set to none meaning the turtles are no longer tied using untie to set the mode to free you need to set tie mode free Code Example Tie System Example Multiple source files The __includes keyword allows you to use multiple source files in a single NetLogo model The keyword begins with two underscores to indicate that the feature is experimental and may change in future NetLogo releases When you open a model that uses the __ includes keyword or if you add it to the top of a model and hit the Check button the includes menu will appear in the toolbar From the includes menu you can select from the files included in this model When you open included files they appear in additional procedures tabs See the Interface Guide for more details You can have anything in external source files n1s that you would normally put in the procedures tab globals breed turtles own patches own breeds own procedure definitions etc Note though that these declarations all share the same namespace That is if you declare a global my global in the procedures tab you cannot declare a global or anything else with the name my global in any file that is included in the model my global will be accessible from all the included files The same would be true if my global were declared in one of the included files Syntax C
303. he turtle is hidden It is no longer necessary to check the bounds using turtle coordinates instead we can just ask NetLogo if a turtle is at the edge of the world There are a couple ways of doing this the simplest is to use the can move primitive 1f not can move distance rt 180 can move merely returns true if the position distance in front of the turtle is inside the NetLogo world false otherwise In this case if the turtle is at the edge of the world it simple goes back the way it came You can also use patch ahead 1 nobody in place of can move If you need to do something smarter that simply turning around it may be useful to use patch at with dx and dy if patch at dx 0 nobody set heading heading if patch at O dy nobody set heading 180 heading This tests whether the turtle is hitting a horizontal or vertical wall and bounces off that wall Programming Guide 131 NetLogo 4 1 2 User Manual In some models if a turtle can t move forward it simply dies exits the system like in Conductor or Mousetraps if not can move distance die If you are moving turtles using setxy rather than forward you should test to make sure the patch you are about to move to exists since setxy throws a runtime error if it is given coordinates outside the world This is a common situation when the model is simulating an infinite plane and turtles outside the view should simply be hidden let new x new value of
304. he turtle s pitch Both dx and dy have changed in this case So dx cos pitch sin heading and dy cos pitch cos heading See also dx dy F face facexyz face agent facexyz X y z Set the caller s heading and pitch towards agent or towards the point x y z If the caller and the target are at the same x and y coordinates the caller s heading will not change If the caller and the target are also at the same z coordinate the pitch will not change either L left left number The turtle turns left by number degrees relative to its current orientation While left in a 2D world only modifies the turtle s heading left in a 3D world may also modify the turtle s pitch and roll See also left tilt up tilt down link pitch link pitch Reports the pitch from end1 to end2 of this link ask link 0 1 print link pitch 7 prints towards pitch other end of endl of link O 1 Introducing NetLogo 3D 219 NetLogo 4 1 2 User Manual See also link heading pitch load shapes 3d load shapes 3d filename o Loads custom 3D shapes from the given file See the 3D guide for more details You must also add a 2D shape of the same name to the model using the Turtle Shapes Editor Custom shapes override built in 3D shapes and converted 2D shapes max pzcor min pzcor max pzcor min pzcor These reporters give the maximum and minimum z coordinates respectively for patches which determines the size of the world Unlike
305. he words are the keys You can easily retrieve the value for any key in the table but not vice versa How to use Both extensions come preinstalled To use the array extension in your model add a line to the top of your procedures tab extensions array To use the table extension in your model add a line to the top of your procedures tab extensions table You can use both extensions in the same model if you want as follows extensions array table If your model already uses other extensions then it already has an extensions line in it so just add array and or table to the list For more information on using NetLogo extensions see the Extensions Guide Limitation on table keys Table keys may only be strings numbers booleans or lists Lists may be arbitrarily nested lists as long as all the items inside are strings numbers or booleans Array example let a array from list n values 5 0 print a Array and Table Extensions 239 NetLogo 4 1 2 User Manual gt array 0 0 0 0 0 print array length a gt 5 foreach n values 5 array set a print a gt array 0 1 4 9 16 print array item a 0 gt 0 print array item a 3 gt 9 array set a 3 50 print a gt array 0 1 4 50 16 Table example let dict table make table put dict turtle cute table put dict bunny cutest print dict gt table turtle gt cute bunny gt cutest print table length
306. hecked so it s possible to get Infinity or NaN Not a Number as an answer without a runtime error being signaled e A bug in Java causes patch colors imported using import pcolors to be brighter than the original if the original image has a grayscale palette To work around this issue convert the image file to an RGB palette e import pcolors may give slightly different results when running on Java 6 as compared to Java 5 Other bugs e Out of memory conditions are not handled gracefully e the Snap to Grid feature is disabled when zoomed in or out e Drawing and then erasing a line in the drawing may not erase every pixel exactly e 3D graphics don t work on some graphics configurations on others 3D works but 3D full screen mode doesn t e The size of the fonts used in a model s interface can vary somewhat from computer to computer and from platform As a result text that fits in a given space on one computer may nat fit in another To avoid this problem it is advisable to leave some extra space in the sizes of buttons sliders etc e When running a model headless from the command line if the model was created in an earlier NetLogo version it may not work properly Use the GUI to open and resave the model in the current NetLogo version before running it headless Extensions e The GIS extension does not work in applets It hard codes the assumption that data files are stored locally not on the server Windows only bugs
307. hen a participant tries to connect to an activity nothing happens the client appears to hang or gives an error saying that no server was found If your computer or network has a firewall it may be impeding the HubNet server from communicating Make sure that your computer and network are not blocking ports used by the HubNet server ports 9173 9180 The view on the HubNet client is grey e Verify that the Mirror 2D view on clients checkbox in the HubNet Control Center is selected 186 HubNet Guide NetLogo 4 1 2 User Manual e Make sure that the display switch in the model is on e If you have made changes to the size of the view on the server you may need to press the Reset button in the Control Center to ensure the clients get the new size There is no view on the HubNet client Some activities don t have a view on the client If you want to add a view simply select HubNet Client Editor from the Tools Menu and add a view like any other widget Make sure to press the Reset button before having clients log in can t quit a HubNet client You will have to force the client to quit On OS X force quit the application by selecting Force Quit in the Apple menu On Windows press Ctrl Alt Delete to open the Task Manager select HubNet Client and press End Task My computer went to sleep while running a HubNet activity When woke the computer up got an error and HubNet wouldn t work anymore The HubNet server may s
308. here is a bug either in Mac OS X or in the RXTX library that we use for the serial connection which requires you to enter the following commands in the Terminal application Applications Utilities Terminal app before the GoGo board will work sudo mkdir var lock sudo chmod 1777 var lock sudo rm var spool uucp Once you ve completed the previous step you can start NetLogo Open the GoGoMonitor example and press the setup button A dialog will pop up presenting a list of available ports Select the port that the GoGo board is plugged into It might look something like this dev tty KeySeriall Where the words after dev tty might be something related to the brand of adapter you have and include the word serial If you can t figure out which port is the correct one you can find it in the System Profiler Apple Menu gt About This Mac gt More Info After you setup press the ping button it should print true in the command center You should also notice values in the sensor monitors that may be fluctuating slightly If this does not work please contact us at bugs ccl northwestern edu Linux You will need to be able to write to the serial devices normally dev ttys In most Linux distributions this can be set up through the User Manager 264 NetLogoLab and the GoGo Board Extension NetLogo 4 1 2 User Manual Using the GoGo Extension The GoGo Extension comes preinstalled when you download and install NetLogo To use the ext
309. hing in between them That s an empty string If a turtle s label is an empty string no text is attached to the turtle e Test this in the Interface tab by running the model using the setup and go buttons switching the show energy switch back and forth When the switch is on you ll see the energy of each turtle go up each time it eats grass You ll also see its energy going down whenever it moves 62 Tutorial 43 Procedures NetLogo 4 1 2 User Manual 2000 ot Ig 0 55 500 5500 soc 4000 sde 2500 4 4500 esac 4500 6000 150 0 3000 an 150 o 700 E 0 50 aa 730 390 150 300 6 0 7003900 800 0 5500 500 30040 4500 2500 500 0 700 0 2008 40010 300 459800 9500 300 400500 me sob Engso e SOM RPP 60010 9008 1050 0 6000 8500 5500 4000 somo 350 0 35040 z soon 3 4000 250 More procedures Now our turtles are eating let s make them reproduce and die too Let s also make the grass grow back We ll add all three of these of these behaviors now by making three separate procedures one for each behavior e Go to the Procedures tab e Rewrite the go procedure as follows ES gu move turtles eat grass reproduce check death regrow grass end e Add the procedures for reproduce check death and regrow grass as shown below to reproduce ask turtles if energy gt 50 set energy energy 50 hatch 1 set energy 50 Tutorial 3 Procedures 63 NetLogo 4 1 2 Us
310. how NetLogo Dictionary 345 NetLogo 4 1 2 User Manual Note that this command is the file i o equivalent of print and file open needs to be called before this command can be used See also file show file type and file write file read file read This reporter will read in the next constant from the opened file and interpret it as if it had been typed in the Command Center It reports the resulting value The result may be a number list string boolean or the special value nobody Whitespace separates the constants Each call to file read will skip past both leading and trailing whitespace Note that strings need to have quotes around them Use the command file write to have quotes included Also note that the file open command must be called before this reporter can be used and there must be data remaining in the file Use the reporter file at end to determine if you are at the end of the file file open my file data print file read 5 7 Next value is the number 1 gt 6 print length file read 7 Next value is the list 1 2 3 4 gt 4 See also file open and file write file read characters file read characters number Reports the given number of characters from an opened file as a string If there are fewer than that many characters left it will report all of the remaining characters Note that it will return every character including newlines and spaces Also note that the file open command mu
311. how list 1 2 3 4 gt 1 2 3 4 show list gt Note that each of these special commands has a default number of inputs for which no parentheses are required The primitives which have this capability are list word sentence map and foreach Lists of agents Earlier we said that agentsets are always in random order a different random order every time If you need your agents to do something in a fixed order you need to make a list of the agents 110 Programming Guide NetLogo 4 1 2 User Manual instead There are two primitives that help you do this sort and sort by Both sort and sort by can take an agentset as input The result is always a new list containing the same agents as the agentset did but in a particular order If you use sort on an agentset of turtles the result is a list of turtles sorted in ascending order by who number If you use sort on an agentset of patches the result is a list of patches sorted left to right top to bottom If you use sort on an agentset of links the result is a list of links sorted in ascending order first by end1 then by end2 any remaining ties are resolved by breed in the order they are declared in the procedures tab If you need descending order instead you can combine reverse with sort for example reverse sort turtles If you want your agents to be ordered by some other criterion than the standard ones sort uses you ll need to use sort by in
312. ht away But you can also have multiple pens in a plot You can create additional pens by editing the plot and using the controls in the Plot Pens section at the bottom of the edit dialog Each pen should have a unique name You ll be using its name to refer to it in your code in the Procedures tab For a plot with multiple pens you have to specify which pen you want to plot with If you don t specify a pen plotting will take place with the first pen in the plot To plot with a different pen use the set current plot pen command with the name of the pen enclosed in double quotes like this set current plot pen distance Plotting points Programming Guide 119 NetLogo 4 1 2 User Manual The two basic commands for actually plotting things are plot and plotxy With plot you need only specify the y value you want plotted The x value will automatically be O for the first point you plot 1 for the second and so on That s if the plot pen s interval is the default value of 1 you can change the interval The plot command is especially handy when you want your model to plot a new point at every time step Example to setup plot count turtles end to go plot count turtles end Note that in this example we plot from both the setup and go procedures That s because we want our plot to include the initial state of the system We plot at the end of the go procedure not the beginning because we want the plot always
313. ials provided with the distribution Copyright and License Information 9 NetLogo 4 1 2 User Manual e Neither the name of the PicoContainer Organization nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE JTS Topology Suite Copyright c 2001 Vivid Solutions The library is covered by the GNU LGPL Lesser General Public License The text of that license is included in the docs folder which accompanies the NetLogo download and is also available from http Awww gnu org copyleft lesser html JScience Java TM Tools and Libraries for the Advancement of Sciences Copyright C 2006 JScience All rights
314. ich describes the relationship between the two objects interior space boundary space or exterior space Each element will describe the dimension of the intersection of two spaces meaning that it may have one of four possible values e 1 meaning the spaces do not intersect e 0 meaning the dimension of the spaces intersection is zero i e they intersect at a point or set of points e 1 meaning the dimension of the spaces intersection is one i e they intersect along one or more lines e 2 meaning the dimension of the spaces intersection is two i e their intersection is a non empty polygon For example the two polygons x and y shown here GIS Extension 291 NetLogo 4 1 2 User Manual have the following DE 9IM matrix Y Boundary 1 0 1 Which would be reported by the relationship of primitive as the string 212101212 A much more detailed and formal description of the DE 9IM matrix and the associated point set theory can be found in the OpenGIS Simple Features Specification for SQL The objects x and y may be any one of e a VectorDataset in which case the object s spatial representation is the union of all the points lines or polygons the dataset contains e a VectorFeature in which case the object s spatial representation is defined by the point line or polygon the feature contains e A turtle in which case the spatial representation is a point e A link whose spa
315. iguous virtual memory Upgrading to a newer version of Windows may help Running Windows in 64 bit mode instead of 32 bit mode may also help Double check that Windows is actually running in 64 bit mode see Microsoft s FAQ page on 64 bit Windows Can I run NetLogo from the command line without the GUI Yes The easiest way is to set up your model run or runs as a BehaviorSpace experiment No additional programming is required See the BehaviorSpace section of the User Manual for details Another option is to use our Controlling API Some light Java programming is required See the Controlling section of the User Manual for details and sample code Does NetLogo take advantage of multiple processors Only when using BehaviorSpace BehaviorSpace does parallel runs one per processor FAQ Frequently Asked Questions 307 NetLogo 4 1 2 User Manual For a single model run only one processor is used The NetLogo engine is single threaded and we expect it to remain that way We don t have any plans to make it possible to split a single model run across multiple processors or multiple computers Can distribute NetLogo model runs across a cluster or grid of computers Many of the same comments in the previous answer apply It is not possible to split a single model run across multiple computers but you can have each machine in a cluster doing one or more separate independent model runs using either BehaviorSpace or our Controlling API
316. iling or 512K on some Windows systems on how much total RAM it can use If your model exceeds that limit you ll get an OutOfMemoryError dialog If you are using BehaviorSpace note that doing runs in parallel will multiply your RAM usage accordingly Here s how to raise the limit if you need to e Windows Edit this section of the NetLogo 4 1 2 vmoptions file in the NetLogo folder Xmx1024M Macintosh Edit the Contents Info plist file in the NetLogo application package You can reach this file by control clicking the application in the Finder and choosing Show Package Contents from the popup menu The relevant section is this the second number is the one gigabyte ceiling lt key gt VMOptions lt key gt lt string gt XX MaxPermSize 128m Xmx1024M lt string gt Ordinarily you can go as high as two gigabytes 2048M by this method But if your Mac has a 64 bit Intel processor and you are running Mac OS X 10 6 you may be able to go even higher Select the NetLogo application in the Finder choose Get Info on the File menu and then uncheck the Open in 32 bit mode checkbox to enable 64 bit operation which should allow higher Xmx numbers We have not heavily tested 64 bit mode but it seems to work e Other Edit the netlogo sh script or a copy changing the xmx number to the desired value Can use GIS data in NetLogo Yes using the GIS extension See the GIS section of the User Manual A simpler way is to us
317. in older versions of NetLogo the origin does not have to be at the center of the world However the minimum z coordinate has to be less than or equal to O and the maximum z coordinate has to be greater than or equal to 0 Note You can set the size of the world only by editing the view these are reporters which cannot be set See also max pxcor max pycor min pxcor min pycor and world width N neighbors neighbors6 neighbors neighbors6 dx Pg 3D versions of neighbors and neighbors4 Reports an agentset containing the 26 surrounding patches neighbors or 6 surrounding patches neighbors6 show sum values from neighbors count turtles here 7 prints the total number of turtles on the twenty six 7 patches around this turtle or patch ask neighbors6 set pcolor red turns the six neighboring patches red 220 Introducing NetLogo 3D NetLogo 4 1 2 User Manual O orbit down orbit left orbit right orbit up orbit down number orbit left number orbit right number orbit up number ig Rotate the observer around the last point faced Imagine the observer is on the surface of a sphere the last point face is the center of that sphere Up and down orbit along the lines of longitude and right and left orbit along the lines of latitude The observer will remain facing the last point faced so the heading and pitch may change as result of orbiting However because we assume an absolute north pole parallel to the positiv
318. in the HubNet application Client applets and clients run through the HubNet application can be used at the same time in the same activity In order to use a client applet you first have to save the client interface as an applet You can do so by pressing the Save Client As Applet button in the HubNet Client Editor toolbar 4 G abe Button w Save Client As Applet Edit Delete Add To access the client over the Internet you need to put the generated html file and HubNet jar you do not need the model file somewhere that is web accessible on the machine that you intend to run the server on You must run the server on the same computer as you host the client applet or the client applet will not be able to connect to the server due to security restrictions Troubleshooting started a HubNet activity but when participants open a HubNet Client my activity isn t listed On some networks the HubNet Client cannot automatically detect a HubNet server Tell your participants to manually enter the server address and port of your HubNet server which appear in the HubNet Control Center Note The technical details on this are as follows In order for the client to detect the server multicast routing must be available between them Not all networks support multicast routing In particular networks that use the IPsec protocol typically do not support multicast The IPsec protocol is used on many virtual private networks VPNs W
319. in the models in our Models Library A model that does use the capability is the Termites model in the Biology section of Sample Models The go button is a turtle forever button so each termite proceeds independently of every other termite and the observer is not involved at all This means that if for example you wanted to add ticks and or a plot to the model you would need to add a second forever button an observer forever button and run both forever buttons at the same time Note also that a model like this cannot be used with BehaviorSpace Code Example State Machine Example shows how Termites can be recoded in a tick based way without using a turtle forever button At present NetLogo has no way for one forever button to start another Buttons are only started when you press them Lists In the simplest models each variable holds only one piece of information usually a number or a string The list feature lets you store multiple pieces of information in a single variable by collecting those pieces of information in a list Each value in the list can be any type of value a number or a string an agent or agentset or even another list Lists allow for the convenient packaging of information in NetLogo If your agents carry out a repetitive calculation on multiple variables it might be easier to have a list variable instead of multiple number variables Several primitives simplify the process of performing the same Pr
320. inannns 361 INGIUG ESP O o toi did 362 ine ta iLE e OEE o da A a a Danda De do RIO A a nd o 362 is link set is list is number is patch is patch set is string is turtle is turtle set is undirected lidk o ooooonncccccnnccccnnnnnccnnnnonacinononanincnonananano nana nani nnnananos 363 MM A A A aioe ee 363 Ka TRE P EE IEEE A da A dC te na 364 A RC GN AS A 364 O SR A AR ROO MENINA AA OR 364 AO PERO DAR RODAR AN AI RARO E DSR 364 El el jE oro o RR E EI ae RENDER RR RR NERD ak N tes Te ca ts 364 NAS Ties thn NR 365 IVETE 365 AYQUEMAISHIDOA a des 365 E A SL 366 EE io IV iso co8 enn ieccatideanesateneaes E E AE 367 layOU Ulla 368 A O ENA EE EEE pb a eee e Da a ATA eae a E Scie aA he 368 LENO jin ERRAR E 369 S sed dade RO NPR e RREO DR DRE RE ra ad 369 RT SOR asa RE RARO a RITO A ORA RE RREO DER A E 369 fal afeto elfo o PERES O 369 ol Sefa fo pio NR 370 INKESO ese SA pa aa dl as dato DeL O SA A EI E Ad DR UR eich 370 MEE a aae anna Bina NE cad ea IR aba Oued eta Dusan aa a ea Eataa aa 370 A O 370 links own lt liNk DIEeedS gt QOWO ooccccoccconccnonococoncccnnncnnoncnnonancnnncnnoncnnonn nono ncnnonannn nana nanannananas 371 E A EN 371 NR 371 O O O 371 SNOOP anillas 372 A ETA 372 Ml es Due dol ee 372 MAMA AAA o a eens 372 O eed ees 373 MAXSNEOE mesa essa cima aus aci es ON 373 xix NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary XX DENE di A A A EO A 373 MAX PXCOS MAX PYV
321. indows Users Most Windows users should choose the standard NetLogo download which includes a bundled Java 6 which is for NetLogo s private use only other programs on your computer are not affected System Requirements 21 NetLogo 4 1 2 User Manual There are two reasons you might want to use the alternate download without bundled Java 1 You want a smaller download so it arrives faster and uses up less space on your hard drive 2 For specific technical reasons of your own you want to run NetLogo using a different Java than the one we bundle If you think the alternate download might be appropriate for you please read the following Even if you already have Java installed on your computer using that Java may make NetLogo run slowly For maximum performance NetLogo uses a special option called the server VM The default Java Runtime Environment JRE installer from Sun does not install this option It is only included in Sun s Java Development Kit JDK If you are not a Java developer then you probably have the JRE not the JDK and if you use it with NetLogo models will run substantially slower 22 System Requirements Known Issues If NetLogo malfunctions please send us a bug report See the Contacting Us section for instructions Known bugs all systems Language engine bugs e The run and runresult primitives are often not able to read or set variables created with let e Not all mathematical operations are c
322. ink Shapes e Tick Counter e View Updates e Plotting e Strings e Output e File I O e Movies e Perspective e Drawing e Topology e Links e Ask Concurrent e Tie e Multiple source files e Syntax Agents The NetLogo world is made up of agents Agents are beings that can follow instructions Each agent can carry out its own activity all simultaneously In NetLogo there are four types of agents turtles patches links and the observer Turtles are agents that move around in the world The world is two dimensional and is divided up into a grid of patches Each patch is a square piece of ground over which turtles can move Links are agents that connect two turtles The observer doesn t have a location you can imagine it as looking out over the world of turtles and patches When NetLogo starts up there are no turtles yet The observer can make new turtles Patches can make new turtles too Patches can t move but otherwise they re just as alive as turtles and the Programming Guide 93 NetLogo 4 1 2 User Manual observer are Patches have coordinates The patch at coordinates 0 0 is called the origin and the coordinates of the other patches are the horizontal and vertical distances from this one We call the patch s coordinates pxcor and pycor Just like in the standard mathematical coordinate plane pxcor increases as you move to the right and pycor increases as you move up The total number of pat
323. is 6 gt the sum is 9 foreach list turtle 1 turtle 2 3 4 ask 1 fd 2 7 turtle 1 moves forward 3 patches 7 turtle 2 moves forward 4 patches NetLogo Dictionary 349 NetLogo 4 1 2 User Manual See also map 2 forward fd forward number The turtle moves forward by number steps one step at a time If number is negative the turtle moves backward fd 10 is equivalent to repeat 10 jump 1 J fd 10 5 is equivalentto repeat 10 jump 1 jump 0 5 If the turtle cannot move forward number steps because it is not permitted by the current topology the turtle will complete as many steps of 1 as it can then stop See also jump can move fput fput item list Adds item to the beginning of a list and reports the new list 7 suppose mylist is 5 7 10 set mylist fput 2 mylist 7 mylist is now 2 5 7 10 G globals globals var7 This keyword like the breed lt breeds gt own patches own and turtles own keywords can only be used at the beginning of a program before any function definitions It defines new global variables Global variables are global because they are accessible by all agents and can be used anywhere in a model Most often globals is used to define variables or constants that need to be used in many parts of the program H 350 NetLogo Dictionary NetLogo 4 1 2 User Manual hatch hatch lt breeds gt hatch number commands hatch lt breeds gt number comm
324. is made of four kinds of elements Stocks Variables Flows and Links A Stock is a collection of stuff an aggregate For example a Stock can represent a population of sheep the water in a lake or the number of widgets in a factory A Flow brings things into or out of a Stock Flows look like pipes with a faucet because the faucet controls how much stuff passes through the pipe A Variable is a value used in the diagram lt can be an equation that depends on other Variables or it can be a constant A Link makes a value from one part of the diagram available to another A link transmits a number from a Variable or a Stock into a Stock or a Flow System Dynamics Guide 171 NetLogo 4 1 2 User Manual The System Dynamics Modeler figures out how the value of your Stocks change over time by estimating them over and over The estimation isn t always perfect but you can affect its accuracy by changing the value of dt As dt decreases you estimate the model more frequently so it gets more accurate However decreasing dt also makes but the model run more slowly Sample Models There are four models in the Sample Models section of the NetLogo Models Library that use the System Dynamics Modeler All four models explore population growth and in models with predation population decline Exponential Growth and Logistic Growth are simple examples of growth in one stock Wolf Sheep Predation aggregate is an example of a system with multip
325. issue a GetCapabilities request to the server and how to interpret the results The transparency input determines how transparent the new image in the drawing will be Valid inputs range from O completely opaque to 255 completely transparent Acknowledgments The GIS extension makes use of the following open source software libraries for information on copyrights and licenses see the copyright section of the manual e Java Topology Suite e JScience e Java Advanced Imaging e Apache Commons Codec e Apache Jakarta HttpClient e Apache Commons Logging The extension also contains elements borrowed from My World GIS This documentation and the example NetLogo models are in the public domain but the GIS extension itself is not See the file LICENSE txt in the extension gis directory for details 298 GIS Extension FAQ Frequently Asked Questions Feedback from users is very valuable to us in designing and improving NetLogo We d like to hear from you Please send comments suggestions and questions to feedback ccl northwestern edu and bug reports to bugs ccl northwestern edu Questions General e Why is it called NetLogo e How do cite NetLogo in an academic publication e How do cite a model from the Models Library in an academic publication e Where and when was NetLogo created e What programming language was NetLogo written in e What s the difference between StarLogo MacStarLogo StarLogoT and NetLogo e Unde
326. it something that is meaningful in the model All the items in the box below the pen name are settings relevant to that particular pen e Set the color to one of the NetLogo base hues or a custom color using the color swatches e Mode allows you to change the appearance of the plot pen line bar like a bar chart or point like line except the points are not connected e Interval is the amount by which x advances every time you use plot y e If the Show in Legend checkbox is checked the selected pen will be a part of the legend in the upper right hand corner of the plot which can be revealed by clicking on the word Pens on the plot itself For more detailed information on how each of these features works you can see the Plotting Section of the Programming Guide 84 Interface Guide NetLogo 4 1 2 User Manual Sliders Sliders define global variables they are provided as an easy way to change the value of these global variables without changing the underlying code When you place a slider in the Interface tab the edit dialog automatically opens as with all widgets Most of the fields will be familiar However it is important to notice the the minimum maximum and increment fields will take any reporter expression not just constants So for example you could make the minimum min pxcor and the maximum max pxcor and the slider bounds will automatically adjust when you change the size of the world Slider Global variable my slide
327. izontal one click the button with the double headed arrow just to the left of Clear Interface Guide 83 NetLogo 4 1 2 User Manual Plots To show or hide a plot s pens legend click on the word Pens in the upper right corner of a plot If you move the mouse over the white area of a plot the x and y coordinates of the mouse location will appear Note that the mouse location might not correspond exactly to any actual data points in the plot If you need to know the exact coordinates of plotted points use the Export Plot menu item and inspect the resulting file in another program When you create a plot as with all widgets the edit dialog automatically appears e00 Plot Name pla ZO O y S X axis label X min 0 0 X max 10 0 Y axis label Y min 0 0 Y max 10 0 M Autoplot Plot Pens Choose Pen to Edit default H Rename Delete Create Color black A Mode Line HH Interval 1 0 M Show in Legend Custom Color 3 Many of the fields are fairly self explanatory the name of the plot labels for the x and y axes and ranges for the axes If Autoplot is checked the x and y changes will automatically readjust as points are added to the plot if they are outside the current range In the plot pens section of the dialog you can create and customize different pens in this plot You must always have a least one pen in every plot You start out with one named default you probably want to rename
328. k S 410 JA Lo TEIA 23s te RR REEE neared ca biden Sates RR RD A EA A RR es 411 A NE 411 MM O EES I AE a cas o ee de 411 A o a ee A anta Dd Bie aba o Ea 411 A e No llo la 411 SOM DY a A AA AA AAA ad 412 sprout sprout lt breeds gt nan r rn rr rr 413 RLO AAEE E PA E E E EA aga ak O DEE PRERESI PR E AE RAE RPE RN 413 SLAM o E seis liiasapo aaeer tne eget A beats datando ra da auda 413 Stamp eraSe tias sagas AA a Aa 413 siandard de VIA iia cd cds ea set deb le RO cian des 414 Feto LAO O Maa 414 xxii NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary LO Oui OO TOWARAS AA A A a a Da ls A AA A O a e A a A o A US Sa EA ss A A OT turiles at lt breeds gt at rrenan turtles on lt breeds gt 00 errar turiles own lt DreedS gt QWN coocccncnnncnoncnnncnoncnnncnnncnnncnnncnncnnnnnnneroneronerenccines USC NOD ii dd idos USE MI SA od ART GE A USer One Of Aes ea a A eee A a NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary PAD Rel DE A tE E 427 WII lr ida sate 427 with local randomness treat nn no nn nn non anna a rn nn narra narran nar rn nana 428 WithoOuUt iNterruptiON ccccccccncnnccnoncnonononcnnnnnnnnnnnnnonnnnnnnnnnnnnnnnnnnnnrnnnnnnnnnnnnnnnnnnnrnnnrenenoss 428 WO aia is ds a 429 world width World Deight occoccccccccnccnnccnnnononcnnnnnnnnnnnononnnnnnnnnnnnnnnnnnnnnnnnnnnnninnnininiss 429 WIAD ECOIOM stents aia
329. k patches set pcolor ifelse value pxcor gt 0 blue red the left half of the world turns red and 7 the right half turns blue show n values 10 ifelse value lt 5 0 1 gt 0000011111 show reduc ifelse valu 21 gt 22 21 2 1 3 2 5 3 8 3 2 1 gt 8 See also if ifelse import drawing import drawing filename ig Reads an image file into the drawing scaling it to the size of the world while retaining the original aspect ratio of the image The image is centered in the drawing The old drawing is not cleared first Agents cannot sense the drawing so they cannot interact with or process images imported by import drawing If you need agents to sense an image use import pcolors or import pcolors rgb The following image file formats are supported BMP JPG GIF and PNG If the image format supports transparency alpha that information will be imported as well import pcolors import pcolors filename Reads an image file scales it to the same dimensions as the patch grid while maintaining the original aspect ratio of the image and transfers the resulting pixel colors to the patches The image is centered in the patch grid The resulting patch colors may be distorted since the NetLogo color space does not include all possible colors See the Color section of the Programming Guide import pcolors may be slow for some images particularly when you have many patches and a large image with m
330. k turtle O create link to turtle 1 show in link neighbor turtle 1 prints false show out link neighbor turtle 1 prints true ask turtle 1 show in link neighbor turtle 0 prints true show out link neighbor turtle 0 prints false out lt breed gt neighbors out link neighbors out lt breed gt neighbors out link neighbors Reports the agentset of all the turtles that have directed links from the caller crt 4 ask turtle 0 create links to other turtles ask out link neighbors set color pink turtles 1 3 turn pink ask turtle 1 ask out link neighbors set color orange 7 no turtles change colors 77 Since turtle 1 only has in links end out lt breed gt to out link to out lt breed gt to turtle out link to turtle Reports the directed link from the caller to turtle If no link exists then it reports nobody ert 2 ask turtle 0 create link to turtle 1 show out link to turtle 1 shows link 0 1 ask turtle 1 show out link to turtle 0 shows nobody See also in link from link with NetLogo Dictionary 387 NetLogo 4 1 2 User Manual output print output show output type output write output print value output show value output type value output write value These commands are the same as the print show type and write commands except that value is printed in the model s output area instead of in the Command Center If the model does not have a separate
331. l the appearance of links logging allows researchers to record students actions for later analysis built in tick counter for keeping track of model time see language changes below new view update system 0 there are now two view update modes tick based and continuous continuous is the default when you start up NetLogo tick based is the default for most models in the Models Library continuous update mode is useful for non tick based models like Termites but may also be useful during debugging 0 tick based updates are faster for most models and avoid displaying intermediate state 0 buttons no longer have a force view update checkbox most models should use tick and or display instead 4 improved speed slider you can now use the slider to fast forward a model by updating the view less often 0 in tick based update mode going slower pauses between ticks rather than showing intermediate states What s New 17 18 4 4 4 4 4 4 4 4 4 4 e o 4 4 4 NetLogo 4 1 2 User Manual 0 in continuous update mode going slower shows intermediate states you can even go so slow you can watch agents move one at a time new input boxes in Interface tab permit entering text numbers colors or NetLogo code as model parameters arrays and hash tables are now supported via extensions see Arrays 8 Tables section of User Manual new profiler extension lets you measure the running times of your procedu
332. l to its who number ask turtles draw polygon 8 who Programming Guide 95 NetLogo 4 1 2 User Manual Reporter procedures Just like you can define your own commands you can define your own reporters You must do two special things First use to report instead of to to begin your procedure Then in the body of the procedure use report to report the value you want to report to report absolute value number ifelse number gt 0 report number report number end Variables Agent variables Agent variables are places to store values such as numbers in an agent An agent variable can be a global variable a turtle variable a patch variable or a link variable If a variable is a global variable there is only one value for the variable and every agent can access it You can think of global variables as belonging to the observer Turtle patch and link variables are different Each turtle has its own value for every turtle variable and each patch has its own value for every patch variable and the same for links Some variables are built into NetLogo For example all turtles have a color variable and all patches have a pcolor variable The patch variable begins with p so it doesn t get confused with the turtle variable If you set the variable the turtle or patch changes color See next section for details Other built in turtle variables including xcor ycor and heading Other built in p
333. la version we leverage implicit conversions to do this work for us We do so by importing org nlogo api ScalaConversions _ which provides us with two new methods via implicit conversions The first is toLogoLi st which converts Scala Segs to LogoLists as seen in 0 until n toLogoList The second is toLogoOb ject which converts any supported Scala value to the appropriate NetLogo type The conversions provided by toLogoObject are Input Type Output Type String String scala Boolean java lang Boolean java lang Boolean scala Float java lang Float java lang Double scala Double java lang Double ava lang Double scalaSeg_____ org togoapiLogoList The conversions to LogoList are recursive Nested collections in the input will be converted to nested LogoLists in which all elements have been converted by toLogoObject ExtensionObjects on the other hand are not recursed into Using the toLogoOb ject conversion is simple Just call the method on an an Any Example 7 toLogo0bject 3 Create a JAR To create an extension s JAR file first compile your classes as usual either from the command line or using an IDE Important As when compiling Java you must add NetLogo jar from the NetLogo distribution to your classpath when compiling Extensions Guide 235 NetLogo 4 1 2 User Manual Here s an example of how compiling your extension might look from the command line mkdir p classes create the classes subfo
334. lack E Mode Line Interval 1 0 M Show in Legend Cancer 50 Next you will need to create two pens e With the Plot dialog box still open press the Create button in the Plot dialog to create a new pen e Enter the name of this pen as turtles and press OK in the Enter Pen Name dialog see image below e Press the Create button in the Plot dialog again to create a second new pen e Enter the name of this pen as grass and press OK in the Enter Pen Name dialog see image below e Select the color for this pen and change it to green e Select OK in the Plot dialog box AAA Plot Name Totals X axis label time Xmin 0 Xmax 10 Y axis label totals Y min 0 Y max 10 Y Autoplot Plot Pens Choose Pen to Edit turtles 27 Delete Color black 34000 IS egend i Enter a name for the pen 3 66 Tutorial 43 Procedures NetLogo 4 1 2 User Manual Note that when you create the plot you can also set the minimum and maximum values on the X and Y axes You ll want to leave the Autoplot checkbox checked so that if anything you plot exceeds the minimum and maximum values for the axes the axes will automatically grow so you can see all the data e Setup and run the model again You can now watch the plot being drawn as the model is running Your plot should have the general shape of the one below though your plot might not look exactly the same Remember that we left Autoplot on This allows
335. layout spring turtles links 0 2 5 1 lays the nodes in a triangle end layout tutte layout tutte turtle set link set radius The turtles that are connected by links in link set but not included in turtle set are placed in a circle layout with the given radius There should be at least 3 agents in this agentset The turtles in turtle set are then laid out in the following manner Each turtle is placed at centroid or barycenter of the polygon formed by its linked neighbors The centroid is like a 2 dimensional average of the coordinates of the neighbors The purpose of the circle of anchor agents is to prevent all the turtles from collapsing down to one point After a few iterations of this the layout will stabilize This layout is named after the mathematician William Thomas Tutte who proposed it as a method for graph layout to make a tree set default shape turtles circle crt 6 ask turtle 0 create link with turtle 1 create link with turtle create link with turtle 3 N ask turtle 1 create link with turtle 4 create link with turtle 5 place all the turtles with just one neighbor on the perimeter of a circle and then place the remaining turtles inside this circle spread between their neighbors repeat 10 layout tutte turtles with link neighbors 1 links 12 end left It 368 NetLogo Dictionary NetLogo 4 1 2 User Manual left number The turtle turns left by nu
336. lder if it does not exist scalac classpath NetLogo jar d classes src IntegerList java You will need to change the classpath argument to point to the NetLogo jar file from your NetLogo installation This command line will compile the java and put the class files in the classes subfolder Then create a JAR containing the resulting class files and the manifest exactly as was done with the Java classes For example jar cvfm example scala jar manifest txt C classes 4 Use your extension in a model Using a Scala extension is the same as using a Java extension However there is one caveat NetLogo ships with a stripped down version of scala library jar While most common classes Array List Map are present it may be best to check especially if your extension makes use of less common classes To check which classes are present in the scala library jar that ships with NetLogo in the lib directory inside the NetLogo directory type this at the command line S jar tf scala library jar If you find that a class used by your extension is missing either by checking manually or via a ClassNotFound exception there is still hope Place a copy of a full version of scala library jar into the root of your extensions directory in this case example scala Or since the full scala library jar is large over 4 megabytes you may wish to prepare a smaller jar containing only the specific missing classes you need to supply Extension develo
337. le stocks influencing one another lt models a predator prey ecosystem using the System Dynamics Modeler Wolf Sheep Predation docked is an example of a model that runs both the a System Dynamics model and an agent based model side by side It runs the System Dynamics implementation of Wolf Sheep Predation next to the agent based Wolf Sheep Predation model from the Biology section of Sample Models How it Works To open the System Dynamics Modeler choose the System Dynamics Modeler item in the Tools menu The System Dynamics Modeler window will appear 606 System Dynamics Modeler P Edit IA Delet SY Check O Stock O variable e Flow gt Link dt 1 0 Edit growth rate E F population Diagram Tab The Diagram tab is where you draw your System Dynamics diagram 172 System Dynamics Guide NetLogo 4 1 2 User Manual The toolbar contains buttons to edit delete and create items in your diagram Creating Diagram Elements Stock ID Variable Flow Link A System Dynamics diagram is made up of four kinds of components Stocks Variables Flows and Links Stock To create a Stock press the Stock button in the toolbar and click in the diagram area below A new Stock appears Each Stock requires a unique name which becomes a global variable Stocks also require an Initial value lt can be a number a variable a complex NetLogo expression or a call to a NetLogo report
338. le up and stop moving This is modeling how traffic jams can form without any cause such as an accident a broken bridge or an overturned truck No centralized cause is needed for a traffic jam to form You may alter the settings and observe a few runs to get a full understanding of the model As you are using the Traffic Basic model have you noticed any additions you would like to make to the model Looking at the Traffic Basic model you may notice the environment is fairly simple a black background with a white street and number of blue cars and one red car Changes that could be made to the model include changing the color and shape of the cars adding a house or street light creating a stop light or even creating another lane of traffic Some of these suggested changes are cosmetic and would enhance the look of the model while the others are more behavioral We will be focusing more on the simpler or cosmetic changes throughout most of this tutorial Tutorial 43 will go into greater detail about behavioral changes which require changing the Procedures tab To make these simple changes we will be using the Command Center The Command Center The Command Center is located in the Interface Tab and allows you to enter commands or directions to the model Commands are instructions you can give to NetLogo s agents turtles patches links and the observer Refer to the Interface Guide for details explaining the different parts of
339. led first which takes time however compiled bits of code are cached by NetLogo and thus using run on the same string over and over is much faster than running on different bits of code See also runresult Note that you can t use run to define or redefine procedures Note that running code through run or runresult may be many times slower than running the same code directly runresult runresult string This agent interprets the given string as a NetLogo reporter and runs it reporting the result obtained The code runs in the agent s current context which means it has access to the values of local variables myself and so on The code must be compiled first which takes time however compiled bits of code are cached by NetLogo and thus using runresult on the same string over and over is much faster than running on different bits of code See also run Note that running code through run or runresult may be many times slower than running the same code directly S scale color scale color color number range1 range2 Reports a shade of color proportional to number 404 NetLogo Dictionary NetLogo 4 1 2 User Manual If range1 is less than range2 then the larger the number the lighter the shade of color But if range2 is less than range7 the color scaling is inverted If number is less than range1 then the darkest shade of color is chosen If number is greater than range2 then the lightest shade of color is chosen
340. let ml matrix from column list 1 4 7 2 5 8 3 6 911 a 3x3 matrix print ml gt matrix ETEZS TEA eE Ga JS let m2 ml m2 refers to the same matrix object as ml let m3 matrix copy ml m3 is a new copy containing ml s data matrix set ml 0 0 100 now ml is changed print ml Matrix Extension 245 NetLogo 4 1 2 User Manual gt matrix 10023 456 7891 print m2 gt matrix 10023 4 5 617897913 Notice that m2 was also changed when ml was changed print m3 gt matrix 123 45 6 78 9 matrix pretty print text matrix pretty print text matrix Reports a string that is a textual representation of the matrix in a format that is reasonably human readable when displayed Matrix modification and math operations matrix get matrix get matrix row i col j Reports the numeric value at location row i col j in the given matrix matrix get row matrix get row matrix row i Reports a simple not nested NetLogo list containing the elements of row i of the given matrix matrix get column matrix get column matrix col j Reports a simple not nested NetLogo list containing the elements of col j of the given matrix matrix set matrix set matrix row i col j new value Changes the given matrix by setting the location row i col j to new value matrix set row matrix set row matrix row i simple list Changes the given matrix matrix by replacing the row at row i with the contents of the simple not
341. lk Example in the Code Examples section of the Models Library to see these code snippets in use patch ahead 1 is reporting the same patch my turtle is already standing on Why See the answer two answers up It s the same issue This might not be the meaning of ahead you were expecting With patch ahead you must specify the distance ahead that you want to look If you want to know the next patch a turtle would cross into if it moved forward continuously it is possible to find that out See Next Patch Example in the Code Examples section of the Models Library How do give my turtles vision You can use in radius to let a turtle see a circular area around it Several primitives let the turtle look at specific points The pat ch ahead primitive is useful for letting a turtle see what is directly in front of it If you want the turtle to look in another direction besides straight ahead try patch left and ahead and patch right and ahead If you want the turtle to have a full cone of vision use the in cone primitive You can also find out the next patch a turtle would cross into if it moved forward continuously See Next Patch Example in the Code Examples section of the Models Library 312 FAQ Frequently Asked Questions NetLogo 4 1 2 User Manual Can agents sense what s in the drawing layer No If you want to make marks that agents can sense use patch colors I m getting numbers like 0 10000000004 and 0 799999999
342. ll go away e Switch to the Procedures tab e Type the following EO Setup clear all create turtles 100 ask turtles setxy random xcor random ycor end When you re done the Procedures tab looks like this O 06 NetLogo Untitled Interface Information _ Procedures 2 Y Procedures w Find Check to setup clear all create turtles 100 ask turtles setxy random xcor random ycor end Note that the lines are indented different amounts Most people find it helpful to indent their code like this but it is not mandatory It makes the code easier to read and change Your procedure began with the word to and ended with the word end Every new procedure you create will begin and end with these two words Let s look at what you typed in and see what each line of your procedure does eto setup begins defining a procedure named setup e clear all resets the world to an initial empty state All the patches turn black and any turtles you might have created disappear Basically it wipes the slate clean for a new model 52 Tutorial 3 Procedures NetLogo 4 1 2 User Manual run ecreate turtles 100 creates 100 turtles They start out standing at the origin that is the center of patch 0 0 e ask turtles tells each turtle to run independently the commands inside the brackets Every command in NetLogo is run by some agent ask is a command too Here the observer is running the ask
343. ll of comments which begin with semicolons Comments let you mix an explanation the code right in with the code itself You might use comments to help others understand your model or you might use them as notes to yourself In the Procedures tab comments are gray so your eyes can pick them out easily turtles own energy for keeping track of when the turtle is ready to reproduce and when it will die to setup clear all setup patches setup turtles do plots end to setup patches ask patches set pcolor green end to setup turtles create turtles number uses the value of the number slider to create turtles ask turtles setxy random xcor random ycor end to go if ticks gt 500 stop 7 stop after 500 ticks move turtles eat grass check death reproduce regrow grass buck 7 increase the tick counter by 1 each time through do plots end to move turtles ask turtles right random 360 forward 1 set energy energy 1 when the turtle moves it looses one unit of energy end to eat grass ask turtles if pcolor green set pcolor black 7 the value of energy from grass slider is added to energy set energy energy energy from grass 70 Tutorial 3 Procedures NetLogo 4 1 2 User Manual ifelse show energy set label energy the label is set to be the value of th nergy set label the label is set to an empty text value end to reproduce
344. lled temporary because they vanish when the plot is cleared by the clear plot clear all plots or clear all commands To create a temporary plot pen use the create temporary plot pen command Once the pen has been created you can use it like any ordinary pen By default the new pen is down is black in color has an interval of 1 and plots in line mode Commands are available to change all of these settings see the Plotting section of the NetLogo Dictionary Using a Legend You can show the legend of a plot by selecting the Show legend checkbox in the edit dialog If you don t want a particular pen to show up in the legend you can uncheck the Show in Legend checkbox for that pen also in the edit dialog Conclusion Not every aspect of NetLogo s plotting system has been explained here See the Plotting section of the NetLogo Dictionary for information on additional commands and reporters related to plotting Many of the Sample Models in the Models Library illustrate various advanced plotting techniques Also check out the following code examples Code Examples Plot Axis Example Plot Smoothing Example Rolling Plot Example Strings To input a constant string in NetLogo surround it with double quotes The empty string is written by putting nothing between the quotes like this Most of the list primitives work on strings as well but first string gt tring but last string gt strin empty gt true
345. logy the turtle will complete as many steps of 1 as it can and stop See also forward jump can move base colors base colors Reports a list of the 14 basic NetLogo hues print base colors gt 5 15 25 35 45 55 65 75 85 95 105 115 125 135 ask turtles set color one of base colors 7 each turtle turns a random base color ask turtles set color one of remove gray base colors 77 each turtle turns a random base color except for gray beep beep Emits a beep Note that the beep sounds immediately so several beep commands in close succession may produce only one audible sound Example beep emits one beep repeat 3 beep 7 emits 3 beeps at once 7 so you only hear one sound repeat 3 beep wait 0 1 produces 3 beeps in succession separated by 1 10th of a second When running headless this command has no effect behaviorspace run number behaviorspace run number Reports the current run number in the current BehaviorSpace experiment starting at 1 If no BehaviorSpace experiment is running reports 0 326 NetLogo Dictionary NetLogo 4 1 2 User Manual both ends both ends Reports the agentset of the 2 nodes connected by this link CEE 2 ask turtle O create link with turtle 1 ask link 0 1 ask both ends set color red turtles 0 and 1 both turn red breed breed MS This is a built in turtle and link variable It holds the agentset of all turtles or links of the sam
346. lot s current pen is set to the pen named penname a string If no such pen exists in the current plot a runtime error occurs set default shape set default shape turtles string set default shape breed string gt Specifies a default initial shape for all turtles or for a particular breed When a turtle is created or it changes breeds it shape is set to the given shape This command doesn t affect existing turtles only turtles you create afterwards The specified breed must be either turtles or a breed defined by the breed keyword and the specified string must be the name of a currently defined shape In new models the default shape for all turtles is default Note that specifying a default shape does not prevent you from changing an individual turtle s shape later turtles don t have to be stuck with their breed s default shape create turtles 1 new turtle s shape is default create cats 1 7 new turtle s shape is default set default shape turtles circle create turtles 1 new turtle s shape is circle create cats 1 7 new turtle s shape is circle set default shape cats cat set default shape dogs dog create cats 1 7 new turtle s shape is cat ask cats set breed dogs all cats become dogs and automatically Change their shape to dog See also shape set histogram num bars set histogram num bars number Set the current plot pen s plot interval so that given the current x range
347. m Reports the item in list of choices selected by the user value may be of any type but is typically a string 1f yes user one of Set up the model yes no 424 NetLogo Dictionary NetLogo 4 1 2 User Manual setup user yes or no user yes or no value Reports true or false based on the user s response to value value may be of any type but is typically a string if user yes or no Set up the model setup V variance variance list Reports the sample variance of a list of numbers Ignores other types of items Note that this computes an unbiased estimate of the variance for a sample rather than for a whole population using Bessel s correction The sample variance is the sum of the squares of the deviations of the numbers from their mean divided by one less than the number of numbers in the list show variance 2 7 4 3 5 gt 3 7 W wait wait number Wait the given number of seconds This needn t be an integer you can specify fractions of seconds Note that you can t expect complete precision the agent will never wait less than the given amount but might wait slightly more repeat 10 fd 1 wait 0 5 See also every watch NetLogo Dictionary 425 NetLogo 4 1 2 User Manual watch agent Puts a spotlight on agent In the 3D view the observer will also turn to face the subject See also follow subject reset perspective watch me watch me watch me
348. m Requirements Saved AppletS ooooocccccononooconccccnnnnccconnnanononnncccnnnnanonnnnncnnnnnnnannnnnnnos 21 System Requirements Da id ds 21 Technical Java Details for Windows US8IS ooocccconocccccnnnoccncnnncancnnnanonononananononananononnanccnnnnns 21 AN AAA O TEN 23 Known bugs all SYSTeMS oocococccocccnncconccinnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennnnennnnnnin 23 Language engine DUYS ccccccccccnccnncconcnoncnoncnnnnonononononnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennneniness 23 OUBE BUGS a A RR DU CNA 23 EXTENSIONS A A AA AA a 23 ii EAT Ko E E E ganda dona se sadna dia E 23 Macintosh only bugs aee araaaeaa anna anna area nenarenarenarenanenarenanenaneas 24 Linux UNIX 0nly DUAS ui 24 Known issues with HubNet erre narra nn nano anna n nr na narra nara nn 24 Contacting US tais E nabo Po llS dao i bk eat loga dana sb ada lt pe tte diet et heeled 25 WebSite 25 Feedback Questions Ete sic iii ii AA a a eb nee 25 REDOING BUGS i ida A A A A Ai Ravi 25 Sample AP 27 Ata Pany seoa e a A SNS RETO PE REIS SAD ND SPIDER ERRO ae 27 Challenge veria UA RN RR RREO ND A AAA 29 Thinking With ele eee 30 AAIEN Ea E E EE ee bo 30 Tutorial 17 Models coin airada aida 31 Sample Model Wolf Sheep Predation oooooccccccnnnnoconccononnncccnnnannoncnnccnnnnnnnnnnnncnnnnnnnnnnnnnnnos 31 Controlling the Model BUHTOAS 00a io 32 Controlling speed Speed SHOOK ctra 33 Adjusting Settings
349. make my own 3D shapes NetLogo automatically interprets 2D shapes so they are extruded like a cookie cutter shape in the 3D view You can also use the primitive load shapes 3d to load shapes described in an external file in a custom format described in the Custom Shapes section Currently we do not import shapes in any standard formats though we may allow this in the future Dictionary Commands and Reporters Turtle related primitives distancexyz distancexyz nowrap dz left patch at patch at heading pitch and distance tilt down tilt up right roll left roll right setxyz towards pitch towards pitch nowrap towards pitch xyz towards pitch xyz nowrap turtles at Patch related primitives distancexyz distancexyz nowrap neighbors neighbors6 patch patch at patch at heading pitch and distance Agentset primitives at points breeds at turtles at World primitives max pzcor min pzcor random pzcor random zcor world depth load shapes 3d Observer primitives face facexyz orbit down orbit left orbit right orbit up oxcor oycor ozcor setxyz zoom Link primitives link pitch Built In Variables Introducing NetLogo 3D 217 NetLogo 4 1 2 User Manual Turtles zcor pitch roll Patches pzcor A at points agentset at points x1 y 1 z1 x2 y2 z2 Reports a subset of the given agentset that includes only the agents on the patches the given distances away from this agent The distances are specified as a list of three item lists wh
350. mark are reserved Scope NetLogo is lexically scoped Local variables including inputs to procedures are accessible within the block of commands in which they are declared but not accessible by procedures called by those commands Comments The semicolon character introduces a comment which lasts until the end of the line There is no multi line comment syntax Structure A program consists of optional declarations globals breed turtles own patches own lt BREED gt own in any order followed by zero or more procedure definitions Multiple breeds may be declared with separate breed declarations the other declarations may appear once only Every procedure definition begins with to or to report the procedure name and an optional bracketed list of input names Every procedure definition ends with end In between are zero or more commands 138 Programming Guide NetLogo 4 1 2 User Manual Commands and reporters Commands take zero or more inputs the inputs are reporters which may also take zero or more inputs No punctuation separates or terminates commands no punctuation separates inputs Identifiers must be separated by whitespace or by parentheses or square brackets So for example a b is a single identifier but a b c d e contains five identifiers All commands are prefix All user defined reporters are prefix Most primitive reporters are prefix but some arithmetic operators boolean operator
351. matrix regress below Because it is impossible to take the natural log of zero or a negative number matrix forecast compound growth will result in an error if it finds a zero or negative number in data list 7 a compound growth extrapolation of the next item in the list print matrix forecast compound growth 20 25 28 32 35 39 gt 45 60964465307147 21 15254147944863 1 136621034423892 0 9760867518334806 These results tell us 7 the next predicted value is approximately 45 610 x the compound growth trend line is given by Y 21 1525 1 1366 t 7 Y grows by approximately 13 66 each period 5 the R 2 value is roughly 0 9761 a good fit matrix forecast continuous growth matrix forecast continuous growth data list Reports a four element list of the form forecast constant growth rate R2 Whereas matrix forecast compound growth assumes discrete time with Y growing by a given proportion each finite period of time e g a month or a year matrix forecast continuous growth assumes that Y is compounded continuously e g each second or fraction of a second The constant and growth rate are the parameters of the trend line Y constant e growth rate t matrix forecast continuous growth is the calculus analog of matrix forecast compound growth The two will normally yield similar but not identical results as shown in the example below growth rate may of course be negative NOTE The continuous growth fore
352. mber 5 turns red turtle set turtle set value turtle set value value Reports an agentset containing all of the turtles anywhere in any of the inputs The inputs may be individual turtles turtle agentsets nobody or lists or nested lists containing any of the above turtle set self turtle set self turtles on neighbors turtle set turtle 0 turtle 2 turtle 9 turtle set frogs mice See also patch set link set NetLogo Dictionary 419 NetLogo 4 1 2 User Manual turtles turtles Reports the agentset consisting of all turtles show count turtles 7 prints the number of turtles turtles at lt breeds gt at turtles at dx dy lt breeds gt at dx dy x Ed Reports an agentset containing the turtles on the patch dx dy from the caller The result may include the caller itself if the caller is a turtle create turtles 5 setxy 2 3 show count turtles at 1 1 of patch 12 gt 5 If the name of a breed is substituted for turtles then only turtles of that breed are included turtles here lt breed gt here turtles here lt breeds gt here Reports an agentset containing all the turtles on the caller s patch including the caller itself if it s a turtle crt 10 ask turtle 0 show count turtles here gt 10 If the name of a breed is substituted for turtles then only turtles of that breed are included breed cats cat breed dogs dog create cats 5 create dogs 1 ask dogs sh
353. mber degrees If number is negative it turns right length length list length string Reports the number of items in the given list or the number of characters in the given string let let variable value Creates a new local variable and gives it the given value A local variable is one that exists only within the enclosing block of commands If you want to change the value afterwards use set Example let prey one of sheep her if prey nobody ask prey die link link end1 end2 lt breed gt end1 end2 Given the who numbers of the endpoints reports the link connecting the turtles If there is no such link reports nobody To refer to breeded links you must use the singular breed form with the endpoints ask link 0 1 set color green 7 unbreeded link connecting turtle 0 and turtle 1 will turn green ask directed link 0 1 set color red 7 directed link connecting turtle 0 and turtle 1 will turn red See also patch at link heading link heading amp Reports the heading in degrees at least 0 less than 360 from end1 to end2 of the link Throws a runtime error if the endpoints are at the same location ask link 0 1 print link heading NetLogo Dictionary 369 NetLogo 4 1 2 User Manual 7 prints towards other end of endl of link 0 1 See also link length link length link length P Reports the distance between the endpoints of the link ask link 0 1 print link length 7
354. me org nlogo log Logger LINKS gt lt priority value off gt lt category gt lt root gt lt priority value info gt lt appender ref ref A1 gt lt root gt Logging 197 NetLogo 4 1 2 User Manual lt log4j configuration gt This configuration first defines an appender named A1 of type XMLFileAppender with an XMLLayout The appender defines where the logging data goes in this case the data goes into a file In fact if NetLogo is given a FileAppender it will automatically start a new file every time the user opens a new model The XMLFileAppender also does some formatting and writes the appropriate headers to the file The layout defines how to write each individual message Unless you are an advanced user there is no need change or worry about the appender or the layout At the end of the configuration notice the definition of the root logger All of the other loggers descend from the root logger and thus inherit the properties of the root unless explicitly set This case is fairly simple having set up the appender A1 we make that the default appender for the root and all other loggers and make the default priority INFO Messages that are logged at the INFO level or higher will be written messages logged at lower levels will not Note that with only one exception NetLogo always logs at level INFO Sets to globals that don t change the value of the global are logged at level DEBUG Which means that these me
355. milar API which allows embedding only the interface tab not the whole window in another application To access this functionality use the org nlogo lite InterfaceComponent class which extends javax swing JPanel You can use the embedded component much the same way that you use App s static methods Here is the App example converted to use InterfaceComponent import org nlogo lite InterfaceComponent public class Example3 public static void main String argv try final javax swing JFrame frame new Javax swing JFrame final InterfaceComponent comp new InterfaceComponent frame java awt EventQueue invokeAndWait new Runnable public void run frame setSize 1000 700 frame add comp frame setVisible true try comp open models Sample Models Earth Science Fire nlogo catch Exception ex ex printStackTrace 159 comp command set density 62 comp command random seed 0 comp command setup comp command repeat 50 go System out printin comp report burned trees Controlling Guide 203 NetLogo 4 1 2 User Manual catch Exception ex ex printStackTrace The equivalent code in Scala import org nlogo lite InterfaceComponent object Example3 def main args Array String val frame new javax swing JFrame val comp new InterfaceComponent frame wait frame setSize 1000 700 frame add comp
356. min list stock 10 Ifl want Flow A to deplete a Stock before Flow B is calculated can link Flow A to Flow B and modify Flow B to subtract Flow A s value from the stock min list max list 0 stock flow a 10 Link To create a Link click and hold on the starting point for the link a Variable Stock or Flow and drag the mouse to the destination Variable or Flow Working with Diagram Elements When you create a Stock Variable or Flow you see a red question mark on the element The question mark indicates that the element doesn t have a name yet The red color indicates that the Stock is incomplete it s missing one or more values required to generate a System Dynamics model When a diagram element is complete the name turns black System Dynamics Guide 173 NetLogo 4 1 2 User Manual Selecting To select a diagram element click on it To select multiple elements hold the shift key You can also select one or more elements by dragging a selection box Editing To edit a diagram element select the element and press the Edit button on the toolbar Or just double click the element You can edit Stocks Flows and Variables but you can t edit Links Moving To move a diagram element select it and drag the mouse to a new location Editing dt dt 1 0 Edit On the right side of the toolbar is the default dt the interval used to approximate the results of your System Dynamics model To change the value
357. mmands e random and turtles are primitive reporters random takes a single number as an input and reports a random integer that is less than the input in this case between 0 and 9 turtles reports the agentset consisting of all the turtles We ll explain about agentsets later setup and go can be called by other procedures or by buttons Many NetLogo models have a once button that calls a procedure called setup and a forever button that calls a procedure called go In NetLogo you must specify which agents turtles patches links or the observer are to run each command If you don t specify the code is run by the observer In the code above the observer uses ask to make the set of all turtles run the commands between the square brackets clear all and crt can only be run by the observer d on the other hand can only be run by turtles Some other commands and reporters such as set can be run by different agent types Here are some more advanced features you can take advantage of when defining your own procedures Procedures with inputs Your own procedures can take inputs just like primitives do To create a procedure that accepts inputs include a list of input names in square brackets after the procedure name For example to draw polygon num sides len pen down repeat num sides fd len rt 360 num sides end Elsewhere in the program you could ask turtles to each draw an octagon with a side length equa
358. mmands to preserve the value of the variable e g let old varl varl setup set varl old varl This works because even clear a11 doesn t clear the values of local variables made with let Another possible workaround is to change your model s setup procedure to use more specific clearing commands to clear only what you want cleared Why are some of my results cut off in Excel In some versions of Excel spreadsheets can t have more than 256 columns See a Microsoft support article on the subject Possible workarounds include e Use a newer version of Excel such as Excel 2007 Windows or Excel 2008 Mac e Use a different program besides Excel e Ask BehaviorSpace to generate results in table format instead of or in addition to spreadsheet format Excel can read our table format too e Change your experiment so the result has fewer columns Extensions FAQ Frequently Asked Questions 315 NetLogo 4 1 2 User Manual I m writing an extension Why does the compiler say it can t find org nlogo api You need to add NetLogo jar to your classpath when compiling NetLogo jar is included with NetLogo 316 FAQ Frequently Asked Questions NetLogo Dictionary Categories Turtle Patch Agentset Color Control Logic World Perspective Input Qutput Files List String Math Plotting Links Movie System HubNet Special Variables Keywords Constants Categories This is an approximate grouping
359. model can run fast since updating the view takes time that could be used for running the model itself When view updates are off completely the model continues to run in the background and plots and monitors still update but if you want to see what s happening you need to turn view updates back on by rechecking the box Many models run much faster when view updates are off for others it makes little difference 36 Tutorial 1 Models NetLogo 4 1 2 User Manual The size of the view is determined by five separate settings Min and Max X Min and Max Y and Patch Size Let s take a look at what happens when we change the size of the view in the Wolf Sheep Predation model There are more model settings than there s room for in the toolbar The Settings button lets you get to the rest of the settings e Press the Settings button in the toolbar A dialog box will open containing all the settings for the view Model Settings World o 25 25 25 25 a Location of origin Center 4 minimum x coordinate for patches max pxcor 25 maximum x coordinate for patches DYLO minimum y coordinate for patches y E el 25 25 25 25 max pycor 25 Torus 51x 51 maximum y coordinate for patches Y World wraps horizontally Y World wraps vertically View Patch size 9 Font size 14 measured in pixels of labels on agents Tick counter Y Show tick counter Tick counter label ticks Can
360. mple observer gt ask patches set pcolor yellow the observer has to ask the patches to set their pcolor to yellow But when a command is directly given to a group of agents like in the second example patches gt set pcolor white you only have to give the command itself e Press setup What happened Why did the View revert back to the old version with the black background and white road Upon pressing the setup button the model will reconfigure itself back to the settings outlined in the Procedures tab The Command Center is not often used to permanently change the model It is most often used as a tool to customize current models and allows for you to manipulate the NetLogo world to further answer those What if questions that pop up as you are investigating the models The Procedures tab is explained in the next tutorial and in the Programming Guide Now that we have familiarized ourselves with the Command Center let s look at some more details about how colors work in NetLogo Working With Colors You may have noticed in the previous section that we used two different words for changing color color and pcolor What is the difference between color and pcolor e Choose turtles from the popup menu in the Command Center or use the tab key e Type set color blue and press return What happened to the cars Think about what you did to make the cars turn blue and try to make the patches turn red If you try to a
361. n commands1 See error message carefully show 1 1 print error message gt 1 carefully show 1 0 print error message gt division by zero ceiling ceiling number Reports the smallest integer greater than or equal to number show ceiling 4 5 gt 5 show ceiling 4 5 gt 4 See also floor round precision clear all ca clear all a Resets all global variables to zero and calls reset ticks clear turtles clear patches clear drawing clear all plots and clear output NetLogo Dictionary 329 NetLogo 4 1 2 User Manual clear all plots clear all plots Clears every plot in the model See clear plot for more information clear drawing cd clear drawing ig Clears all lines and stamps drawn by turtles clear links clear links w Kills all links See also die clear output clear output a Clears all text from the model s output area if it has one Otherwise does nothing clear patches cp clear patches is Clears the patches by resetting all patch variables to their default initial values including setting their color to black clear plot clear plot In the current plot only resets all plot pens deletes all temporary plot pens resets the plot to its default values for x range y range etc and resets all permanent plot pens to their default values The default values for the plot and for the permanent plot pens are set in the plot Edit dialog whic
362. n a context where an integer is expected the fractional part is simply discarded So for example crt 3 5 creates three turtles the extra 0 5 is ignored The range of integers is 9007199254740992 2153 about 9 quadrillion Calculations that exceed this range will not cause runtime errors but precision will be lost when the least significant binary digits are rounded off in order fit the number into 64 bits With very large numbers this rounding can result in imprecise answers which may be surprising show 2 60 1 2 60 gt Lrue Calculations with smaller numbers can also produce surprising results if they involve fractional quantities since not all fractions can be precisely represented and roundoff may occur For example 112 Programming Guide NetLogo 4 1 2 User Manual SHOW A ES O Daf 6 IN ES gt 0 9999999999999999 show 1 9 te DO LL A AS LA OA TO SAS gt 1 0000000000000002 Any operation which produces the special quantities infinity or not a number will cause a runtime error Scientific notation Very large or very small floating point numbers are displayed by NetLogo using scientific notation Examples show 0 000000000001 gt 1 0E 12 show 50000000000000000000 gt 5 0E19 Numbers in scientific notation are distinguished by the presence of the letter E for exponent It means times ten to the power of so for example 1 0E 12 means 1 0 times 10 to the 12 power show 1
363. n and orientation of the Observer When in follow or ride mode the observer position and orientation are the same as the turile s Note that follow and ride are functionally exactly the same the difference is only visual in the 3D view When in watch mode the Observer does not move but updates to face the target agent Introducing NetLogo 3D 215 NetLogo 4 1 2 User Manual e Press the setup button again so you are back to the default orientation e Press the orbit right button How did the view change Was it what you expected How is it similar or different from using the mouse controls e Take a little time to experiment with orbit roll and zoom buttons notice similarities and differences to the mouse controls The direction of the the orbit commands refer to the direction that the Observer moves That is imagine that the Observer is on the surface of a sphere the center of the sphere is the point that the Observer is facing represented by the blue cross by default 0 0 0 The Observer will always face the center of the sphere and the radius of the sphere will remain constant The directions up down left and right refer to moving along the lines of latitude and the lines of longitude of the sphere When you zoom the radius of the sphere changes but the center and the Observer s orientation in relation to the center of the sphere will remain the same e Press one of the setxyz buttons How does the view change How do t
364. n from the file or file write file print file type or file show to write out to the file Note that you can only open a file for reading or writing but not both The next file i o primitive you use after this command dictates which mode the file is opened in To switch modes you need to close the file using file close Also the file must already exist if opening a file in reading mode When opening a file in writing mode all new data will be appended to the end of the original file If there is no original file a new blank file will be created in its place You must have write permission in the file s directory If you don t want to append but want to replace the file s existing contents use file delete to delete it first perhaps inside a carefully if you re not sure whether it already exists Note that the string can either be a file name or an absolute file path If it is a file name it looks in whatever the current directory is This can be changed using the command set current directory It is defaulted to the model s directory file open my file in txt print file read line gt First line in file File is in reading mode file open C NetLogo my file out txt 7 assuming Windows machine file print Hello World File is in writing mode See also file close file print file print value Prints value to an opened file followed by a carriage return This agent is not printed before the value unlike file s
365. n other words the asked agents will run one at a time Not until one agent completely finishes the entire body of the ask does the next agent start Note that even the old ask was never truly concurrent we simulated concurrent execution by interleaving execution among the agents using a turn taking mechanism described in the NetLogo FAQ We have made this change because in our experience users often wrote models that behaved in unexpected ways due to the simulated concurrency but rarely wrote models that benefited from the simulated concurrency Models exhibiting unexpected behavior could usually be fixed by adding the without interruption command in the right places but it was difficult for users to know whether that command was needed and if so where In NetLogo 4 0 without interruption is no longer necessary unless your model uses ask concurrent or a turtle or patch forever button containing code that depends on simulated concurrency In most models all uses of without interruption can be removed The simulated concurrency formerly employed by ask is still accessible in three ways e You may use the ask concurrent primitive instead of ask to get the old simulated concurrency Transition Guide 145 NetLogo 4 1 2 User Manual e Commands issued in the Command Center directly to turtles patches or links have an implied ask concurrent e Turtle patch and link forever buttons have an implied ask concurrent as well Note that ask
366. n row 1 column 2 gt 6 matrix set m 1 2 10 change the 6 to a 10 print m gt matrix Eo Pb ae aol aoe toed LIS let m2 matrix make identity 3 Matrix Extension 243 NetLogo 4 1 2 User Manual print m2 gt matrix 100 J 0103 00157 print matrix times m m2 multiplying by the identity changes nothing gt matrix EF hae 3 114 510 13 7 make a new matrix with the middle 1 changed to 1 let m3 matrix set and report m2 1 1 1 print m3 gt matrix 100 0 10 0017 print matrix times m m3 gt matrix EAS Ano dE print matrix to row list matrix plus m2 m3 gt 2 0 0 0 O 0 0 0 2 Matrix Primitives Matrix creation conversion to from lists matrix make constant matrix make identity matrix from row list matrix from column list matrix to row list matrix to column list matrix copy matrix pretty print text Matrix data retrieval and manipulation matrix get matrix get row matrix get column matrix set matrix set row matrix set column matrix swap rows matrix swap columns matrix set and report matrix dimensions matrix submatrix Math operations matrix times scalar matrix times matrix times element wise matrix plus scalar matrix plus matrix inverse matrix transpose matrix real eigenvalues matrix imaginary eigenvalues matrix eigenvectors matrix det matrix rank matrix cond matrix trace Advanced features matrix solve matrix forecast linear growth matrix forecast compound
367. n running code directly you should avoid using these primitives on fresh strings in performance critical code Can I have more than one model open at a time One instance of NetLogo can only have one model open at a time We plan to change this in a future version You can have multiple models open by opening multiple instances of NetLogo though On Windows and Linux simply start the application again On a Mac you ll need to duplicate the application not the whole folder just the application itself in the Finder then open the copy The copy takes up only a very small amount of additional disk space Can change the choices in a chooser on the fly At present no In a future version of NetLogo we plan to support this Can divide the code for my model up into several files Yes this is available on an experimental basis using the __ includes keyword Programming How is the NetLogo language different from the StarLogo and StarLogoT languages How do convert my StarLogo or StarLogoT model to NetLogo 310 FAQ Frequently Asked Questions NetLogo 4 1 2 User Manual We don t have a document that specifically summarizes the differences between these programs If you have built models in StarLogo or StarLogoT before then we suggest reading the Programming Guide section of this manual to learn about NetLogo particularly the sections on Ask and Agentsets Looking at some of the sample models and code examples in the Mod
368. n the user presses the mouse button has the tag View The second message sent when the user releases the mouse button has the tag Mouse Up Both messages consist of a two item list of the x and y coordinates For example to turn any patch that was clicked on by the client red you would use the following NetLogo code if hubnet message tag View ask patches with pxcor pycor set pcolor red round item 0 hubnet message and round item 1 hubnet message Plot Updates on the Clients If plot mirroring is enabled in the HubNet Control Center and a plot in the NetLogo model changes and a plot with the exact same name exists on the clients a message with that change is sent to the clients causing the client s plot to make the same change For example let s pretend there is a HubNet model that has a plot called Milk Supply in NetLogo and the clients Milk Supply is the current plot in NetLogo and in the Command Center you type plot 5 This will cause a message to be sent to all the clients telling them that they need to plot a point with a y value of 5 in the next position of the plot Notice if you are doing a lot of plotting all at once this can generate a lot of plotting messages to be sent to the clients 194 HubNet Authoring Guide Logging NetLogo s logging facility allows researchers to record students actions for later analysis Logging in NetLogo once initiated is invisible to the user The research
369. n this tab you will find an explanation of the model suggestions on things to try and other information You may want to read the Information tab before running a model or you might want to just start experimenting then look at the Information tab later What would happen to the sheep population if there was more initial sheep and less initial wolves at the beginning of the simulation e Turn the grass switch off e Set the initial number sheep slider to 100 34 Tutorial 1 Models NetLogo 4 1 2 User Manual e Set the initial number wolves slider to 20 e Press setup and then go e Let the model run for about 100 time ticks Try running the model several times with these settings What happened to the sheep population Did this outcome surprise you What other sliders or switches can be adjusted to help out the sheep population e Set initial number sheep to 80 and initial number wolves to 50 This is close to how they were when you first opened the model e Set sheep reproduce to 10 0 e Press setup and then go e Let the model run for about 100 time ticks What happened to the wolves in this run When you open a model all the sliders and switches are on a default setting If you open a new model or exit the program your changed settings will not be saved unless you choose to save them Note in addition to sliders and switches some models have a third kind of setting called a chooser
370. narananana 153 Additional tiles a as 153 EXTENSION SA A A A A ava nied 153 Using an alternate jar lOCatiON ooccccccccnccnnccnnncnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnninnninnnnss 153 EVE nisi c nice cce caaeceaecaaenaaecaaanananaaanaaaaaaa aaa a aaa aaaaanaaannaaa 154 Getting the rgRiversion cds 154 Increasing the available memory eee ease rea reeareesaresaee o 154 Features not supported in appleis eee eee eeaaeeaa ease eesaeesaneaa 154 Shapes Editor Guide cta ide 155 G tting STO iaa 155 IMPOMING SHADES circa ra ERA Rae ERA LOM LU E UR add das ga 155 Creating and editing turtle SDapes ccccooooccccnncccconnnononnnononoconananononcnnnnnnnnnnnonnnnnnnnnnnnannnnnnnnnos 157 NE NR AN EN NO 157 PREVIEWS ta A A IA A AS 158 Overlappia shape S n aaa 158 Bake enc DENEA AEA A PE ee ota E E DA E ato e e E 158 COM E REINA elves Sele TEE E A E E EE 158 Other DULONS a A a a A sda a Jo Sastre na dd 158 Snape derrito A RR O 158 Keeping a shape ear eeeetaaeaeaa aeee rena anna anna cana cana nana nana nana cana nanananaa 159 Creating and editing link SHADES cuca dada 159 Changing link shape prop ries ssa senisesta als tagaa o ais ia Sad ca ad dae ede aa 159 Using Shapes Ina model sas da aati CDI TARSO acedida 160 NetLogo 4 1 2 User Manual Table of Contents Behavi0rSpace QUIdO ii A A A Ea 161 What is BonaviGhS pace tna ai 161 Why Behavior Space Zisi orioa i dic 161 HOW TE A PANE EEA ENE ocd
371. nce gt Cellular Automata The forever buttons that let the user draw in the view use the display command so the user can see what they are drawing even though the tick counter is not advancing Choosing a mode Advantages of tick based updates over continuous updates include 1 Consistent predictable view update behavior which does not vary from computer to computer or from run to run 2 Continuous updates can confuse the user of your model by letting them see model states they aren t supposed to see which may be misleading 3 Increased speed Updating the view takes time so if one update per tick is enough then enforcing than there is only one update per tick will make your model faster 4 Since setup buttons don t advance the tick counter they are unaffected by the speed slider this is normally the desired behavior As mentioned above most models in our Models Library now uses tick based updates 118 Programming Guide NetLogo 4 1 2 User Manual Continuous updates are useful for models in which execution is not divided into short discrete phases An example in the Models Library is Termites See also however the State Machine Example model which shows how to re code Termites using ticks Even for models that would normally be set to tick based updates it may be useful to switch to continuous updates temporarily for debugging purposes Seeing what s going on within a tick instead of only seeing the end result of a ti
372. nce you are done exploring the Wolf Sheep Predation model you may want to take some time just to explore some of the other models available in the Models Library The Models Library The library contains five sections Sample Models Perspective Demos Curricular Models Code Examples and HubNet Computer Activities Sample Models The Sample Models section is organized by subject area and currently contains more than 210 models We are continuously working on adding new models to it so come visit this section at a later date to view the new additions to the library Some of the folders in Sample Models have folders inside them labeled unverified These models are complete and functional but are still in the process of being reviewed for content accuracy and quality of code Perspective Demos These models are all models that are also in Sample Models however they are slightly modified to demonstrate NetLogo s perspective features Curricular Models These are models designed to be used in schools in the context of curricula developed by the CCL at Northwestern University Some of these are models are also listed under Sample Models others are unique to this section See the info tabs of the models for more information on the curricula they go with Code Examples These are simple demonstrations of particular features of NetLogo They ll be useful to you later when you re extending existing models or building new ones For ex
373. nd 3D Views Command Center Plots Sliders Agent Monitors e Information Tab e Procedures Tab e Includes Menu Menus On Macs if you are running the NetLogo application the menubar is located at the top of the screen On other platforms the menubar is found at the top of the NetLogo window File Edit Tools Zoom Tabs Help NetLogo Untitled The functions available from the menus in the menubar are listed in the following chart Chart NetLogo Menus Models Library JA collection of demonstration models Save As Applet Used to save a web page in HTML format that has your model embedded in it as a Java applet Prit Sends the contents of the currently showing tab to your printer Export World Saves all variables the current state of all turtles and patches the drawing the plots the output area and the random state information to a file Interface Guide 73 NetLogo 4 1 2 User Manual Export Plot Saves the data in a plot to a file Export All Plots Saves the data in all the plots to a file FExportView Save a picture of the current view 2D or 3D to a file in PNG format Export Interface Save a picture of the current Interface tab in PNG format Export Output Save the contents of the output area or the output section of the ommand center to a file Import World Load a file that was saved by Export World Import Patch Load an image into the patches see the import pcolors comman
374. nd ahead patch left and ahead angle distance patch right and ahead angle distance Reports the single patch that is the given distance from this turtle in the direction turned left or right the given angle in degrees from the turtle s current heading Reports nobody if the patch does not exist because it is outside the world If you want to find a patch in a given absolute heading rather than one relative to the current turtle s heading use patch at heading and distance instead ask patch right and ahead 30 1 set pcolor green this turtle looks 30 degrees right of its es current heading at the patch 1 unit away and turns Ha that patch green note that this might be the same i patch the turtle is standing on See also patch patch at patch at heading and distance patch set patch set value patch set value1 value Reports an agentset containing all of the patches anywhere in any of the inputs The inputs may be individual patches patch agentsets nobody or lists or nested lists containing any of the above patch set self patch set patch here patch set self neighbors patch set patch here neighbors patch set patch 0 0 patch 1 3 patch 4 2 patch set patch at 1 1 patch at 0 1 patch at 1 1 patch set patch here of turtles patch set neighbors of turtles See also turtle set link set patch size patch size Reports the size of the patches in the view in pixels The size is typically
375. nd initializes your stocks and your converters Converters with a constant value are initialized first followed by the stocks with constant values The remaining stocks are initialized in alphabetical order system dynamics go runs the aggregate model for at time units It computes the values of Flows and Variables and updates the value of Stocks It also calls tick advance with the value of at Converters and Flows with non constant Expressions will be calculated only once when this procedure is called however their order of evaluation is undefined System Dynamics Guide 175 NetLogo 4 1 2 User Manual system dynamics do plot plots the values of Stocks in the aggregate model To use this first create a plot in the main NetLogo window You then need to define a plot pen for each Stock you want to be plotted This procedure will use the current plot which you can change using the set current plot command The System Dynamics Modeler and NetLogo The diagram you create with the System Dynamics Modeler and the procedures generated from your diagram are part of your NetLogo model When you a save the NetLogo model your diagram is saved with it in the same file Tutorial Wolf Sheep Predation Let s create a model of Wolf Sheep Predation with the System Dynamics Modeler Step 1 Sheep Reproduction e Open a new model in NetLogo e Launch the System Dynamics Modeler in the Tools menu ALS zoom Tabs Help Halt Untitled Global
376. nder Program Files on your hard drive unless 306 FAQ Frequently Asked Questions NetLogo 4 1 2 User Manual you installed NetLogo in a different location Add on a new line Dsun java2d ddoffscreen false You can see the details of the Java bug and vote for Sun to fix it here How come NetLogo won t start up on my Linux machine Ideally any Java 5 or later runtime will run NetLogo However some Java implementations do not support features which NetLogo uses such as Java2D and Swing An example is the GNU libgcj based runtime on Linux which comes preinstalled on some Linux distributions users report that NetLogo does not work with this runtime We recommend Sun s Java runtime when using NetLogo on Linux The IBM or OpenJDK builds may also work Ubuntu users should consult http help ubuntu com community Java When I try to start NetLogo on Windows get an error The JVM could not be started Help A nearly certain fix is to use a text editor to edit the NetLogo 4 1 2 vmoptions file found in the NetLogo directory by default in CAProgram Files Xmx1024M Try changing the 1024M a smaller number like 512M This should permit NetLogo to start although the lower heap size limit may affect your ability to run models with very large numbers of agents See How big can my model be If running with the lower heap size limit is unacceptable read on Some Windows systems have trouble allocating large amounts of cont
377. nder what license is NetLogo released Is the source code available 302 Do you offer any workshops or other training opportunities for NetLogo 302 NetLogo 4 1 2 User Manual Table of Contents FAQ Frequently Asked Questions Are there any Neil ogo TexIDOOKS css ai bd 303 Is NetLogo available in a Spanish version Chinese version your language here AIE RERA A es cee A AA RP O E e AE LALA A de 303 Is NetLogo compiled or interpreted occccnononoocnccncccnnnnnononnnnnnnnnnnnononnnccnnnncnnnnnnnnnnnnos 303 Has anyone built a model of exe 2 iii 303 Are NetLogo models runs scientifically reproducible nono 303 Will NetLogo and NetLogo 3D remain separate erre 304 DOWNIG AGING assassino al Dat GR AR NS 304 Can have multiple versions of NetLogo installed at the same time 304 I m on a UNIX system and can t untar the download Why2 nee 304 How do install NetLogo unattended ooccccccnnonoconcccnccoconnnononccnnnnncccnnnnnnnnnnnnncncnannnns 305 On Windows how do configure the Java installation that the without Java INStANSRUSSS 2 283 ns ses Logo de SE nega tiara o tetrad Sale 305 ADDICTS sarau assina gu sda A A ap 305 tried to run one of the applets on your site but it didn t work What should do 305 When running my model as an applet get the following error java lang OutOfMemoryError Java heap sp
378. ndom seeds see the Random Numbers section of the Programmer s Guide You may specify values either by listing the values you want used or by specifying that you want to try every value within a given range For example to give a slider named number every value from 100 to 1000 in increments of 50 you would enter number Poor so 000i Or to give it only the values of 100 200 400 and 800 you would enter number 100 200 400 800 Be careful with the brackets here Note that there are fewer square brackets in the second example Including or not including this extra set of brackets is how you tell BehaviorSpace whether you are listing individual values or specifying a range Also note that the double quotes around the variable names are required You can vary as many settings as you want including just one or none at all Any settings that you do not vary will retain their current values Not varying any settings is useful if you just want to do many runs with the current settings What order you list the variables in determines what order the runs will be done in All values for a later variable will be tried before moving to the next value for an earlier variable So for example if you vary both x and y from 1 to 3 and x is listed first then the order of model runs will be x 1 y 1 x 1 y 2 x 1 y 3 x 2 y 1 and so on Repetitions Sometimes the behavior of a model can vary a lot from run to run even if the settings don t c
379. net message source of the message the name of the client the message came from 190 HubNet Authoring Guide NetLogo 4 1 2 User Manual On an enter message we create a turtle with a user id that matches the hubnet message source which is the name that each user enters upon entering the activity it is guaranteed to be unique to create new student create students 1 set user id hubnet message sourc set label user id set step size 1 send info to clients end At this point we set any other client variables to default values and send them to the clients if appropriate We declared a student s own variable for every interface element on the client that holds state that is anything that would be a global variable on the server sliders choosers switches and input boxes It is important to make sure that these variables stay synchronized with the values visible on the client When the clients logout they send an exit message to the server which gives you a chance to clean up any information you have been storing about the client in this case we merely have to ask the appropriate turtle to die to remove student ask students with user id hubnet message source die end All other messages are interface elements identified by the hubnet message tag which is the name that appears in the client interface Every time an interface element changes a message is sent to the server Unless you store the sta
380. ng of the leaf turtle is also changed by the same amount If the link dies the tie relation is removed ert 2 fd 3 7 creates a link and ties turtle 1 to turtle 0 ask turtle 0 create link to turtle 1 tie See also untie tie mode tie mode This is a built in link variable It holds a string that is the name of the tie mode the link is currently in Using the tie and untie commands changes the mode of the link You can also set tie mode to free to create a non rigid joint between two turtles see the Tie section of the Programming Guide for details By default links are not tied See also tie untie timer timer Reports how many seconds have passed since the command reset timer was last run or since NetLogo started The potential resolution of the clock is milliseconds Whether you get resolution that high in practice may vary from system to system depending on the capabilities of the underlying Java Virtual Machine See also reset timer NetLogo Dictionary 417 NetLogo 4 1 2 User Manual Note that the timer is different from the tick counter The timer measures elapsed real time in seconds the tick counter measures elapsed model time in ticks to to procedure name to procedure name input Used to begin a command procedure to setup clear all crt 500 end to circle radius crt 100 fd radius end to report to report procedure name to report procedure name input1 Used to
381. ng the same version of NetLogo and begin your model run with the same random seed In general we suggest you write your model so that it does not depend on the exact details of how ask concurrent works We make no guarantees that its semantics will remain the same in future versions of NetLogo Tie Tie connects two turtles so that the movement of one turtles affects the location and heading of another Tie is a property of links so there must be a link between two turtles to create a tie relationship When a link s tie mode is set to fixed or free endl and end2 are tied together If the link is directed end is the root agent and end2 is the leaf agent That is when end1 moves using 4 jump setxy etc end2 also moves the same distance and direction However when end2 moves it does not affect endl 136 Programming Guide NetLogo 4 1 2 User Manual If the link is undirected it is a reciprocal tie relationship meaning if either turtle moves the other turtle will also move So depending on which turtle is moving either turtle can be considered the root or the leaf The root turtle is always the turtle that initiates the movement When the root turtle turns right or left the leaf turtle rotates around the root turtle the same amount as if a stiff were attaching the turtles When tie mode is set to fixed the heading of the leaf turtle changes by the same amount If the tie mode is set to free the heading of t
382. nge color use its coordinates e In the bottom of the patch monitor enter set pcolor blue and press return Typing a command in a turtle or patch monitor addresses only that turtle or patch You can also talk to a single patch from the Command Center e In the Command Center enter ask patch 19 0 set pcolor green and press return What s Next At this point you may want to take some time to try out the techniques you ve learned on some of the other models in the Models Library In Tutorial 3 Procedures you can learn how to alter and extend existing models and build your own models 50 Tutorial 2 Commands Tutorial 43 Procedures This tutorial leads you through the process of building a complete model built up stage by stage with every step explained along the way Agents and procedures In Tutorial 42 you learned how to use the command center and agent monitors to inspect and modify agents and make them do things Now you re ready to learn about the real heart of a NetLogo model the Procedures tab You ve already used types of agents you can give commands to in NetLogo patches turtles links and the observer Patches are stationary and arranged in a grid Turtles move over that grid Links connect two turtles The observer oversees everything that s going on and does whatever the turtles patches and links can t do for themselves All four types of agents can run NetLogo commands All three can also run proc
383. nies the NetLogo download and is also available from http www gnu org copyleft lesser html JHotDraw For the system dynamics modeler NetLogo uses the JHotDraw library which is Copyright c 1996 1997 by IFA Informatik and Erich Gamma The library is covered by the GNU LGPL Lesser General Public License The text of that license is included in the docs folder which accompanies the NetLogo download and is also available from http www gnu org copyleft lesser html Copyright and License Information 5 NetLogo 4 1 2 User Manual MovieEncoder For movie making NetLogo uses code adapted from sim util media MovieEncoder java by Sean Luke distributed under the MASON Open Source License The copyright for that code is as follows This software is Copyright 2003 by Sean Luke Portions Copyright 2003 by Gabriel Catalin Balan Liviu Panait Sean Paus and Dan Kuebrich All Rights Reserved Developed in Conjunction with the George Mason University Center for Social Complexity By using the source code binary code files or related data included in this distribution you agree to the following terms of usage for this software distribution All but a few source code files in this distribution fall under this license the exceptions contain open source licenses embedded in the source code files themselves In this license the Authors means the Copyright Holders listed above and the license itself is Copyright 2003 by Sean Luke The Author
384. nnnnnnnnnnnnnnnnnnnneness 13 Version 4 1 December 2009 oooccccoconcnnccccoconccccncononnoncnncnnoncnnnnnononnnnnononronnnnonrnnnnnencnnencaninnnnns 14 Version 4 0 5 December 200Dl occccooonnnnccccoccnncccnconcnnoncnnnnnoncnnonnononcnnnononrnnonnnnrnnnnnoncnnnnnenonennos 17 Version 4 0 4 November 200B l occooonccnccccoccnccccoconcnncnconcnnoncnnonnononnnnnononrononnnnrnnnnnoncnnennenenennns 17 Version 4 0 September 2007 ius es aa 17 Version 3 1 April 2006 cintia ita 19 Versi n 3 0 September 2005 ita A dE md 19 Version 2 1 December 2004 oooccccoconcnnccccoconccccnconcnnonconcnnononnnnnononnnnnononronnnnonrnnennoncnnnnnenonnonos 19 Version 2 0 2 August 2004 oooooocooccconcconcconononcnncnnnnnoncnnnonononononnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnoss 19 Version 2 0 December 2003B oocccccoconcnnccccocnnccccnconcnnoncnnnnnoncnnonnononnnnnononronnnnnnrnnnnnencnnennoninnones 19 Version 1 3 JUNE 200 sites rage re a atri ca Enio dese o da Ot s 19 Version 1 2 March 200B oocccooocccnccococonncococoncnconconcnnoncononnononnnnnononnnnnononronnnnnnrnnnnnencnnennenonnones 20 Version July 2002 ea ie a ade tddi 20 Version tO April 2002 mimar to apa AA ad 20 NetLogo 4 1 2 User Manual Table of Contents System Requirements titiritero das it 21 System Requirements Application sesassssaniniissoosa ca ld lcd 21 WING OWS curar ti ista 21 MacOSX aire do a PR e Dl e a a O es A e 21 Other D AS aiii T E AAA 21 Syste
385. nnnnnns 382 NOAA ido 383 Netlog VEO 383 A rnia a ig ss ates Sgt dd aa A a e shuns shane 383 alo io E e VAA DURE E EUR RDNS o 383 NODOAV iaa lara 384 HOARS aae a doa gados IN cado Dos ate Sas N een Nee 384 NO PalcheS sr ses seuss bets hee sn Hanada aad en satan ead SIS lara Maan ee inca nani adora edi aah 384 MOD ss a cote a ale ra a aD le e ORE ee eh ae e rs ed Rie alia bs 384 A re ee 384 o 385 O O RO 385 A A O A 385 NN 386 DOME A EA A AAA AA AA a 386 OMEN oito dio des a a at o dd e a cd teas het Dia na 386 out lt breed gt neighbor out link Neighbor ooccccccnnnococonncnncccnnnnononnnnnccncnnnnnnnncnnnnnnnns 386 NetLogo 4 1 2 User Manual Table of Contents NetLogo Dictionary out lt breed gt neighbors out link neighbors essere 387 out lt breed gt LO QUEINKLO sessao eres cuudsavergenetzces era e a e ie ii aeeiiaii 387 output print output show output type output write ie 388 Piet cs Sp arta teases st cabia ti e a A iD RS o dei 388 Dalias A A ENE GREEN ino 388 paich ahCad iv A A AA eis Ain ET 388 A RN 389 patch at heading and distance ran r ran 389 Pai ii a A A ada ra 389 patch left and ahead patch right and ahead ccccccnocoooconnnoncnononannnnnnnnncncnnannnonnnnnnnnnnn 390 A O E 390 palCh SIZO ii id 390 DA a NA a Wane Nata 391 DANS OWN sado AD a era aa US CTA SA SS a Pa 391 01070 A Ad ad Saad 391 pen down pd pen erase pe pen up pu rn nr rn rr 391 DE
386. not starting the Controlling Guide 199 NetLogo 4 1 2 User Ma VM in the top level NetLogo directory then libs subdirectory of the NetLogo installation Current working directory nual hould be changed to point to the 1ib The NetLogo application assumes that the current working directory at startup time is the top level of the NetLogo installation Example with GUI Here is a small but complete program that starts the full NetLogo application opens a model moves a slider sets the random seed runs the model for 50 ticks import org nlogo app App public class Examplel public static void main String argv App main argv try d java awt EventQueue invokeAndWait new Runnable public void run try 4 App app open and then prints a result Earth Science models Sample Models Fire nlogo catch java io IOException ex ex printStackTrace 13 app command set density 62 app command random seed 0 App app command setup APp app command repeat 50 System out println App app report burned trees App App go 1 catch Exception ex ex printStackTrace The equivalent code in Scala import java awt EventQueue import org nlogo app App object Examplel def main args Array String App main args wait App app open models Sample Models App app command set density 62 App ap
387. nputs the who numbers of the two turtles it connects And the patch at primitive reporter takes offsets distances in the x and y directions from the first agent In the example above the turtle with who number 0 is asked to get the patch east and no patches north of itself You can also select a subset of turtles or a subset of patches or a subset of links and ask them to do something This involves a concept called agentsets The next section explains this concept in detail When you ask a set of agents to run more than one command each agent must finish before the next agent starts One agent runs all of the commands then the next agent runs all of them and so on For example if you write Programming Guide 101 NetLogo 4 1 2 User Manual ask turtles fd 1 set color red first one turtle moves and turns red then another turtle moves and turns red and so on But if you write it this way ask turtles fd 1 ask turtles set color red first all of the turtles move After they have all moved they all turn red Another form of the ask command with a different ordering rule is also available See Ask Concurrent below Agentsets An agentset is exactly what its name implies a set of agents An agentset can contain either turtles patches or links but not more than one type at once An agentset is not in any particular order In fact it s always in a random order And every time you use it the agentse
388. ns without interruption if you need the old style concurrent behavior use ask concurrent turtle who numbers are now never reused until clear turtles or clear all all numbers are now represented internally using double precision floating point the operator only adds numbers now it doesn t work on strings or lists anymore models must be changed by hand to use word instead for strings and sentence instead for numbers create turtles now makes turtles with random headings and colors to get evenly spaced turtles with sequential colors and id numbers use create ordered turtles cro for short extension primitives must now by default be referred to using the extension name e g sound drums instead of just drums new uphill uphi114 downhill and downhi114 commands for doing hill climbing replace old reporters with same names new tick counter primitives tick ticks tick advance reset ticks new primitive of replaces VARIABLE of value from values from What s New NetLogo 4 1 2 User Manual other new primitives a11 other move to turtle set patch set link set no turtles no patches no links tie untie min n of max n of with local randomness file flush base colors plot pen exists import pcolors rgb netlogo applet Version 3 1 April 2006 e topologies wrapping at world edges now optional e automatically randomized ordering of agentsets e experimental link primitives Version 3 0 Septemb
389. ns 2 4 19 and earlier but we have observed the problem on more recent kernel versions We assume the problem is Linux specific and does not happen on other Unix based systems We are not sure if the problem ever occurs in practice during actual NetLogo model runs or only occurs in the context of our testing regimen The bug in the Sun s Java VM and not in NetLogo itself We hope that only the exp reporter is affected but we can t be entirely certain of this NetLogo users are encouraged to visit http developer java sun com developer bugParade bugs 5023712 html free registration required and vote for Sun to fix this bug e If NetLogo cannot find the font Lucida menus will be illegible This has been known to happen on Fedora Core 3 after upgrading packages Restarting the X Font Server xfs has resolved the problem in all reported cases Known issues with HubNet See the HubNet Guide for a list of known HubNet issues 24 Known Issues Contacting Us Feedback from users is very valuable to us in designing and improving NetLogo We d like to hear from you Web Site Our web site at ccl northwestern edu includes our mailing address and phone number It also has information about our staff and our various research activities Feedback Questions Etc For help using NetLogo try this group http groups yahoo com group netlogo users If you have feedback suggestions or questions you may write us at feedback ccl northwest
390. ns Project web site e Bug Hunters Camouflage students hunt bugs and camouflaging emerges e Dice Stalagmite HubNet students roll dice and explore the space of dependent and independent events e Disease A disease spreads through the simulated population of students e Disease Doctors A slight modification to the Disease activity where some students can recover from the disease e Gridlock Students use traffic lights to control the flow of traffic through a city e Polling Ask students questions and plot their answers e Root Beer Game An adaptation of a popular game created at MIT in the early 1960s that shows how small delays in a distribution system can create big problems e Sampler Students engage in statistical analysis as individuals and as a classroom Through these activities students discover the meaning and use of basic concepts in statistics e Tragedy of the Commons Students work as farmers sharing a common resource Clients There are two ways to use the client with computer HubNet through the client application and as a Java applet To use the client application you simply need to launch the HubNet client application that is bundled with NetLogo To use the applet you will need to save the client as an applet and put iton a web server more detailed instructions can be found in the applets section Requirements To use Computer HubNet you need a networked computer with NetLogo installed for the server
391. ntation and or other materials provided with the distribution Neither the name of Sun Microsystems Inc or the names of contributors may be used to endorse or promote products derived from this software without specific prior written permission This software is provided AS IS without a warranty of any kind ALL EXPRESS OR IMPLIED CONDITIONS REPRESENTATIONS AND WARRANTIES INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE OR NON INFRINGEMENT ARE HEREBY EXCLUDED SUN MICROSYSTEMS INC SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES INNO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE PROFIT Copyright and License Information 7 NetLogo 4 1 2 User Manual OR DATA OR FOR DIRECT INDIRECT SPECIAL CONSEQUENTIAL INCIDENTAL OR PUNITIVE DAMAGES HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES You acknowledge that this software is not designed or intended for use in the design construction operation or maintenance of any nuclear facility Matrix3D For 3D matrix operations NetLogo uses the Matrix3D class It is distributed under the following license Copyright c 1994 1996 Sun Microsystems Inc All Rights Reserved Sun grants you
392. number in the range 0 to 140 not including 140 itself that represents the given color specified in the RGB spectrum in NetLogo s color space All three inputs should be in the range 0 to 255 The color reported may be only an approximation since the NetLogo color space does not include all possible colors See approximate hsb for a description of what parts of the HSB color space NetLogo colors cover this is difficult to characterize in RGB terms show approximate rgb 0 0 0 gt 0 black show approximate rgb 0 255 255 gt 85 2 cyan See also extract rgb approximate hsb and extract hsb Arithmetic Operators 4 lt gt lt gt All of these operators take two inputs and all act as infix operators going between the two inputs as in standard mathematical use NetLogo correctly supports order of operations for infix operators The operators work as follows is addition is multiplication is subtraction is division is exponentiation lt is less than gt is greater than is equal to is not equal to lt is less than or equal gt is greater than or equal Note that the subtraction operator always takes two inputs unless you put parentheses around it in which case it can take one input For example to take the negative of x write x with the parentheses All of the comparison operators also work on strings All of the comparison operators work on agents
393. o Keywords breed directed link breed end extensions globals __includes patches own to to report turtles own undirected link breed Constants Mathematical Constants e 2 718281828459045 pi 3 141592653589793 Boolean Constants false true Color Constants black 0 gray 5 white 9 9 red 15 orange 25 brown 35 yellow 45 green 55 lime 65 320 NetLogo Dictionary NetLogo 4 1 2 User Manual turquoise 75 cyan 85 sky 95 blue 105 violet 115 magenta 125 pink 135 See the Colors section of the Programming Guide for more details A abs abs number Reports the absolute value of number show abs 7 gt 7 show abs 5 gt 5 acos acos number Reports the arc cosine inverse cosine of the given number The input must be in the range 1 to 1 The result is in degrees and lies in the range O to 180 all all agentset reporter Reports true if all of the agents in the agentset report true for the given reporter Otherwise reports false as soon as a counterexample is found If the agentset is empty reports true The reporter must report a boolean value for every agent either true or false otherwise an error occurs if all turtles color red show every turtle is red See also any NetLogo Dictionary 321 NetLogo 4 1 2 User Manual and condition and condition2 Reports true if both condition and condition are true Note that if condition is
394. o random number generator to the integer part of number The seed may be any integer in the range supported by NetLogo 9007199254740992 to 9007199254740992 See the Random Numbers section of the Programming Guide for more details random seed 47822 show random 100 gt 50 show random 100 gt 35 random seed 47822 show random 100 gt 50 show random 100 gt 35 random xcor random ycor random xcor random ycor NetLogo Dictionary 397 NetLogo 4 1 2 User Manual Reports a random floating point number from the allowable range of turtle coordinates along the given axis x or y Turtle coordinates range from min pxcor 0 5 inclusive to max pxcor 0 5 exclusive horizontally vertically substitute y for x ask turtles 77 move each turtle to a random point setxy random xcor random ycor See also random pxcor random pycor read from string read from string string Interprets the given string as if it had been typed in the Command Center and reports the resulting value The result may be a number list string or boolean value or the special value nobody Useful in conjunction with the user input primitive for converting the user s input into usable form show read from string 3 read from string 5 gt 8 show length read from string 1 2 3 gt 3 crt read from string user input Make how many turtles the number of turtles input by the user are created r
395. o use it things to explore ways to extend the model and NetLogo features 890 NetLogo Wolf Sheep Predation Interface _ Information Procedures 2 PF Find Edit This model explores the stability of predator prey ecosystems Such a system is called unstable if it tends to result in extinction for one or more species involved In contrast a system is stable if it tends to maintain itself over time despite fluctuations in population sizes There are two main variations to this model In the first variation wolves and sheep wander randomly around the landscape while the wolves look for sheep to prey on Each step costs the wolves energy and they must eat sheep in order to replenish their energy when they run out of energy they die To allow the naniilatinn ta enantiniia aarh uinlf ar chaan hee a fivad nrahabhiliti af ranrardurina at aarh tima We recommend reading the Information tab before starting the model The Information tab explains what system is being modeled and how the model was created This display of the Information tab is not editable To edit the content of the Info tab click the Edit button or double click on a word which will also scroll you to the location you clicked on and highlight the word 606 NetLogo Wolf Sheep Predation Interface Procedures LP Find WHAT IS IT This model explores the stability of predator prey ecosystems Such a system is called unstable if it tends to
396. oadcast view This broadcasts the current state of the 2D view in the NetLogo model to all the Computer HubNet Clients It does nothing for Calculator HubNet Note This is an experimental primitive and its behavior may change in a future version See the HubNet Authoring Guide for details and instructions hubnet clear override hubnet clear overrides hubnet clear override client agent or set variable name hubnet clear overrides client Remove overrides from the override list on client hubnet clear override removes only the override for the specified variable for the specified agent or agentset hubnet clear overrides removes all overrides from the specified client See also hubnet send override hubnet enter message hubnet enter message Reports true if a new computer client just entered the simulation Reports false otherwise hubnet message source will contain the user name of the client that just logged on See the HubNet Authoring Guide for details and instructions hubnet exit message hubnet exit message Reports true if a computer client just exited the simulation Reports false otherwise hubnet message source will contain the user name of the client that just logged off See the HubNet Authoring Guide for details and instructions hubnet fetch message hubnet fetch message If there is any new data sent by the clients this retrieves the next piece of data so that it can be accessed by hubnet message hubn
397. odel file e min pycor lt number gt override world size setting in model file e max pycor lt number gt override world size setting in model file 166 BehaviorSpace Guide NetLogo 4 1 2 User Manual model is required If you don t specify experiment you must specify setup file By default no results are generated so you ll usually want to specify either t able or spreadsheet or both If you specify any of the world dimensions you must specify all four Examples It is easiest if you create your experiment setup ahead of time in the GUI so it is saved as part of the model To run an experiment setup saved in a model here is an example command line java server Xmx1024M cp NetLogo jar org nlogo headless Main model Fire nlogo N xperiment experimentl table For this to work Net Logo jar must be present along with the 1ib subdirectory containing necessary libraries Both NetLogo jar and 1ib are included with NetLogo After the named experiment has run the results are sent to standard output in table format as CSV is how you specify standard output instead of output to a file When running the headless Main class as an application it forces the system property java awt headless to be true This tells Java to run in headless mode allowing NetLogo to run on machines when a graphical display is not available Note the user of the server flag to tell Java to optimi
398. oefficients at x to report evaluate polynomial coefficients x report reduce x 1 2 coefficients end 7 evaluate 3x 2 2x 1 at x 4 show evaluate polynomial 3 2 1 4 gt 57 remainder remainder number number2 Reports the remainder when number is divided by number2 This is equivalent to the following NetLogo code numberl int numberl number2 number2 show remainder 62 5 e ee show remainder 8 3 gt 2 See also mod mod and remainder behave the same for positive numbers but differently for negative numbers remove NetLogo Dictionary 399 NetLogo 4 1 2 User Manual remove tem list remove string1 string2 For a list reports a copy of list with all instances of tem removed For strings reports a copy of string2 with all the appearances of string1 as a substring removed set mylist 2 7 4 7 Bob set mylist remove 7 mylist 5 mylist is now 2 4 Bob show remove to phototonic gt phonic remove duplicates remove duplicates list Reports a copy of list with all duplicate items removed The first of each item remains in place set mylist 2 7 4 7 Bob 7 set mylist remove duplicates mylist 5 mylist is now 2 7 4 Bob remove item remove item index list remove item index string For a list reports a copy of list with the item at the given index removed For strings reports a copy of string2 with the character at the given index removed Note
399. of the default dt for your aggregate model press the Edit button next to the dt display and enter a new value Errors When you click the check button or when you edit a stock flow or variable the modeler will automatically generate the NetLogo code the corresponds to your diagram and try to compile that code If there is an error the Procedures tab will turn red and a message will appear and the portion of the the generated code that is causing the trouble will be highlighted use temporary variables so order of computation doesn t affect result let new sheep max list sheep local sheep births gt gt set sheep new sheep tick advance dt end Report value of flow to report sheep births report sheep birth rate shep dt end Plot the current state of the system dynamics model s stocks Call this procedure in your model s GO procedure to system dynamics do plot if plot pen exists sheep set current plot pen sheep plotxy ticks sheep end This should give you a better idea which element in the diagram is causing problem 174 System Dynamics Guide NetLogo 4 1 2 User Manual 0960 Flow Name sheep births Expression sheep birth rate shep Cancel OK Procedures Tab The System Dynamics Modeler generates NetLogo variables and procedures based on the contents of your diagram These procedures are what make the diagram actually perform calculations The Procedures tab in the System
400. of thing Reports the envelope bounding rectangle of thing in GIS coordinates The thing may be an Agent an AgentSet a RasterDataset a VectorDataset or a VectorFeature An envelope consists of a four element list of the form minimum x maximum x minimum y maximum y 282 GIS Extension NetLogo 4 1 2 User Manual gis envelope union of gis envelope union of envelope1 envelope2 gis envelope union of envelope Reports an envelope bounding rectangle that entirely contains the given envelopes An envelope consists of a four element list of the form minimum x maximum x minimum y maximum y No assumption is made about the coordinate system of the arguments though if they are not in the same coordinate system results will be unpredictable gis load coordinate system gis load coordinate system file Loads a new global projection used for projecting or re projecting GIS data as it is loaded from a file The file must contain a valid Well Known Text WKT projection description WKT projection files are frequently distributed alongside GIS data files and usually have a prj filename extension Relative paths are resolved relative to the location of the current model or the user s home directory if the current model hasn t been saved yet The GIS extension does not support all WKT coordinate systems and projections Only geographic GEOGCS and projected PROJCS coordinate systems are supported For projected co
401. ogo 4 1 2 User Manual For the off button it would be very similar gogo talk to output ports a gogo output port off The other set of on and off buttons used to control the second motor would have very similar code except that we would use the second output port b so gogo talk to output ports b We could make our model more interesting by adding a toggle direction button adding a button with the following code which would reverse the direction of motors a and b gogo talk to output ports a b gogo output port reverse A simple sensing project To create a simple sensing project we will assume that you have added the GoGo extension to your model and successfully opened a connection to the GoGo board e adding the extensions command to the Procedures Tab and adding a setup button as previously described For this sensing project we do not need motors but we will need another device a temperature sensor click to see more information about a typical temperature sensor at Digikey s web site Instructions on how to purchase and assemble a temperature sensor can be found in the Making Sensors tutorial on the GoGo Board s web site This is how a temperature sensor will look after it has been assembled 0 The simplest use of a temperature sensor obviously is to display the temperature We could achieve this by adding a monitor to the NetLogo interface with this code gogo sensor
402. ogo the name of the extension and the location of the ClassManager The manifest must contain three tags e Extension Name the name of the extension e Class Manager the fully qualified name of a class implementing org nlogo api ClassManager e Net Logo Extension API Version the version of NetLogo Extension API for which this JAR is intended If a user opens the extension with NetLogo that has a different Extension API version a warning message is issued To tell which version of the Extension API your NetLogo supports choose the About NetLogo item in the Help menu Or you can launch the NetLogo jar with the extension api version argument Here s a manifest for our example extension manifest txt anifest Version 1 0 Extension Name exampl Class Manager SampleExtension tLogo Extension API Version 4 1 The NetLogo Extension API Version line should match the actual version of NetLogo Extension API you are using Make sure even the last line ends with a newline character 4 Create a JAR To create an extension s JAR file first compile your classes as usual either from the command line or using an IDE Important You must add NetLogo jar from the NetLogo distribution to your classpath when compiling Here s an example of how compiling your extension might look from the command line mkdir p classes create the classes subfolder if it does not exist javac classpath NetLogo jar d
403. ogramming Guide 107 NetLogo 4 1 2 User Manual computation on each value in a list The NetLogo Dictionary has a section that lists all of the list related primitives Constant lists You can make a list by simply putting the values you want in the list between brackets like this set mylist 2 4 6 8 Note that the individual values are separated by spaces You can make lists that contain numbers and strings this way as well as lists within lists for example 2 4 3 517 The empty list is written by putting nothing between the brackets like this Building lists on the fly If you want to make a list in which the values are determined by reporters as opposed to being a series of constants use the list reporter The List reporter accepts two other reporters runs them and reports the results as a list If wanted a list to contain two random values might use the following code set random list list random 10 random 20 This will set random 1ist to a new list of two random integers each time it runs To make longer or shorter lists you can use the List reporter with fewer or more than two inputs but in order to do so you must enclose the entire call in parentheses e g list random 10 list random 10 random 20 random 30 For more information see Varying number of inputs Some kinds of lists are most easily built using the n values reporter which allows you to construct a list of a specific length by repeat
404. oint of the link This is fairly simple in a non wrapping world to report link xcor report mean xcor of both ends end to report link ycor report mean ycor of both ends end it is a little bit trickier in a wrapping world but still fairly straightforward to report link xcor let other guy end2 let x 0 ask endl hatch 1 face other guy fd distance other guy of myself 2 set x Xcor die 144 Transition Guide NetLogo 4 1 2 User Manual report x end and similarly for ycor If you used either the size or heading of the link turtles you can use the reporters 1ink 1ength and link heading instead New of syntax We have replaced three different language constructs of with hyphen value from and values from with a single of construct no hyphen new lor of turtle 0 color of turtle 0 size size of lue from turtle 0 size size mean values from turtles size mean size of turtles When of is used with a single agent it reports a single value When used with an agentset it reports a list of values in random order since agentsets are always in random order Note that when opening old models in the new version of value from and values from will automatically be converted to use of instead but some nested uses of these constructs are too complex for the converter and must be converted by hand Serial ask The ask command is now serial rather than concurrent I
405. old value In this tutorial we won t actually write any code like that but nonetheless it is generally good practice to call tick after your agents have done their actions but before you plot Now that your model uses ticks you ll probably want to use the menu at the top of the Interface tab to change from continuous updates to tick based updates That means that NetLogo will only update that is redraw the view that is the display area where you see your agents between ticks never in the middle of a tick This makes your model run faster and ensures a consistent appearance since the updates will happen at consistent times See the Programming Guide for a fuller discussion of view updates Some more details First instead of always using 100 turtles you can have a variable number of turtles e Make a slider variable called number using the monitor icon on the Toolbar and click on an open spot in the Interface Try changing the minimum and maximum values in the slider e Then inside of setup turtles instead of create turtles 100 you can type to setup turtles create turtles number ask turtles setxy random xcor random ycor end Test this change and compare how having more or fewer turtles initially affect the plots over time Second wouldn t it be nice to adjust the energy the turtles gain and lose as they eat grass and reproduce e Make a slider called energy from grass e Make another slider
406. olors In the Procedures tab and elsewhere in the NetLogo user interface program code is color coded by the following scheme e Keywords are green e Constants are orange e Comments are gray e Primitive commands are blue e Primitive reporters are purple e Everything else is black Programming Guide 137 NetLogo 4 1 2 User Manual Notice The remainder of this section contains technical terminology which will be unfamiliar to some readers Keywords The only keywords in the language are globals breed turtles own patches own to to report and end plus extensions and the experimental __ includes keyword Built in primitive names may not be shadowed or redefined so they are effectively a kind of keyword as well Identifiers All primitives global and agent variable names and procedure names share a single global case insensitive namespace local names 1et variables and the names of procedure inputs may not shadow global names or each other Identifiers may contain letters digits and the following ASCII characters 2 1 lt gt 3 _ amp Non ASCII characters are not currently allowed in identifiers We realize this is troublesome for international users and plan to address the issue in a future release Some primitive names begin with two underscores to indicate that they are experimental and are especially likely to change or be removed in future NetLogo releases Identifiers beginning with a question
407. om output let comprop exp item 1 item 0 com output let comR2 item 0 item 1 com output Note the 6 here is because we want to forecast the value at time t 6 print list comcnst comprop 6 comenst comprop comR2 5 this is equivalent to what the matrix forecast continuous growth does let con log data list map ln 20 25 28 32 35 39 let con indep var2 n values length con log data list 0 1 2 5 let con output matrix regress matrix from column list list con log data list con indep var2 let concnst exp item 0 item 0 con output let conrate item 1 item 0 con output let conR2 item 0 item 1 con output print list concnst exp conrate 6 concnst conrate conR2 7 example of a regression with two independent variables Pretend we have a dataset and we want to know how well happiness 7 is correlated to snack food consumption and accomplishing goals let happiness 2 4 5 8 10 let snack food consumed 3 4 3 7 8 let goals accomplished 2 3 5 8 9 print matrix regress matrix from column list list happiness snack food consumed goals accomplished gt 0 14606741573033788 0 3033707865168543 0 8202247191011234 0 9801718440185063 40 8 0 80898876404 7 linear regression happiness 0 146 0 303 snack food consumed 0 820 goals accomplished 7 Since the 0 820 coefficient is higher than the 0 303 coefficient it appears that each goal 252 Matrix Extension NetLogo
408. on You might have bugs in your model If you are using a combination of no wrap and wrap primitives either it doesn t matter for some reason or there is a bug in your model we found a few bugs in our models For example the Conductor model compared distance no wrap to distance to determine whether the next position is wrapped around the world in which case the electron exits the system This is a clever way to solve the problem but unfortunately it is flawed Electrons that wrap in the y direction were also exiting the system which is incorrect in this case The only correct way to exit is to reach the cathode at the left end of the wire If you remove no wrap commands the topology is no longer hard coded into the model so it s easier to test out your model on a different shape of world without a lot of extra coding you may have to add a few extra checks to go from torus to box this is explained more in depth in the How to convert section Note that though we ve removed the no wrap primitives from the dictionary they are still available for you to use we did this so that old models don t have to be changed in order to run How to convert your model When you first open up your model in 3 1 NetLogo will automatically change all cases of screen edge x to min pxcor and all cases of screen edge x to max pxcor and similarly for y Though this is not directly related to the topology changes you may also want to think about whether moving
409. on If NetLogoLite jar and your model are in different directories you must modify the archive and value lines in the HTML code to point to their actual locations For example if you have multiple applets in different directories on the same web server you may want to put a single copy of NetLogoLite jar in one central place and change the archive lines of all the HTML files to point to that one central copy This will save disk space for you and download time for your users Applets 153 NetLogo 4 1 2 User Manual Java requirements Getting the right version Current versions of NetLogo require that your web browser support Java 5 or higher Here s how to get the right Java e If you re on Windows Vista XP or 2000 you need to download the Java browser plugin from http www java com en download windows manual jsp e If you re on Mac OS X you need Mac OS X 10 4 or higher NetLogo 4 0 was the last version to support Mac OS X 10 2 and 10 3 e If you re on Linux or another Unix you will need version 5 or higher of the Sun Java Runtime Environment It is available for download at http www java com Check your browser s home page for information about installing the Java plugin If you think you have the right browser and plugin but it still doesn t work check your browser s preferences to make sure that Java is enabled The following web site may be helpful for figuring out what Java you have and getting the right version
410. on my patch turtles here with color red 7 patches on right side of view patches with pxcor gt 0 102 Programming Guide NetLogo 4 1 2 User Manual all turtles less than 3 patches away turtles in radius 3 the four patches to the east north west and south patches at points 1 0 0 1 1 0 0 1 Shorthand for those four patches neighbors4 7 turtles in the first quadrant that are on a green patch turtles with xcor gt 0 and ycor gt 0 and pcolor green 7 turtles standing on my neighboring four patches turtles on neighbors4 all the links connected to turtle 0 my links of turtle 0 Note the use of other to exclude this agent This is common Once you have created an agentset here are some simple things you can do e Use ask to make the agents in the agentset do something e Use any to see if the agentset is empty e Use a11 to see if every agent in an agentset satisfies a condition e Use count to find out exactly how many agents are in the set And here are some more complex things you can do e Pick a random agent from the set using one of For example we can make a randomly chosen turtle turn green ask one of turtles set color green Or tell a randomly chosen patch to sprout a new turtle ask one of patches sprout 1 e Use the max one of Or min one of reporters to find out which agent is the most or least along some scale For example to remove the richest turtle
411. on strings not lists Of course the NetLogo language also contains many additional features not found in most other Logos most importantly agents and agentsets 140 Programming Guide Transition Guide Many models created in earlier versions of NetLogo also work in NetLogo 4 1 However some models will need changes If your old model isn t working this section of the User Manual may be able to help you What issues you need to be aware of depends on how old your model is The older the NetLogo version it was made with the more issues you may need to be aware of This section does not list every change that was made in the NetLogo versions discussed It covers only the changes that are most likely to be issues for users For a complete list of changes see the What s New section e Since NetLogo 4 0 e Since NetLogo 3 1 e Since NetLogo 3 0 Since NetLogo 4 0 Combining set and of The following syntax is no longer supported set lt variable gt of lt agent gt lt value gt Commands of this form must be rewritten using ask ask lt agent gt set lt variable gt lt value gt Or if the new value must be computed by the asking agent and not by the agent whose variable is being set OPTION 1 using let let new value lt value gt ask lt agent gt set lt variable gt new value 7 OPTION 2 using myself ask lt agent gt set lt variable gt value of myself So for example this se
412. oooocconccconnnoonccccononccononannnonnnnncnnnnnnnnnnnnnnncnnnnnannnnnnnennnnnn 194 Plot Updates on Me Clients an adds 194 LOA RR RD O RARE 195 STAR Lole le 101S 1E E A A SD EE E E 195 Mac OS X or WiNdQOWS Se 195 Linux and others sas a A a A das 195 Using logging a A A Cedo pad ba a 195 Where logs are StOred oococcccnicocicononenineninenenennninenenenenennnnnnnnrnnr rr r rr 195 How to configure the logging OUtpUt ooooooocccccccnnonononccnnoncnnnnnononocnnnnncocnnnnn non nnnnncnnnnnnnnos 197 Advanced Conmigo ida 198 Controilng Guide ici T 199 Starting a Java VM for Neto aos 199 Recommended options for both GUI and headless ia 199 Additional recommended options for GUI only rrenan 199 Current working dITectory ccoooonooocccccnccnnonoonnncccnnnnccononnnnnnnnnnncnnnnnnn no nrrnnncnnnnnannnorennnnnnnns 200 Example WIEN in 200 Example headl sS atuais atas A Aia 201 Example embedding sis aa e cnn ad ceia a dn dd a dad ago 203 GONCIUSION A Lisa e A a det ia ADO E Da dias SEL ASAS a ca 204 Mathematica Link cada den and 205 WV nais ss ras tati d 205 Wihai can l do Withitt a A Siad dao do o S 205 SEE APA o oops EPA GAS SEN te SGA stn ipa ght i US UNE ale eg ESA scat 205 Dl iaa A A at 206 KNOWS eS ic a a e E N T E E E 207 CrediiS A E E ta E E E dd ET O 207 INTFOGUCING NOTE OGO Diane E 209 Introductorio letrado edna oad 209 SUSVVOHAS Cuica ads A a SA a nd ade ND E eat A Ae dp el 209
413. op note sound play drum sound play drum drum velocity Plays a drum sound play drum ACOUSTIC SNARE 64 sound play note sound play note instrument keynumber velocity duration Plays a note for a specified duration in seconds The agent does not wait for the note to finish before continuing to next command 7 play a trumpet at middle C for two seconds sound play note TRUMPET 60 64 2 sound play note later sound play note later delay instrument keynumber velocity duration Waits for the specified delay before playing the note for a specified duration in seconds The agent does not wait for the note to finish before continuing to next command 7 in one second play a trumpet at middle C for two seconds sound play note later 1 TRUMPET 60 64 2 sound play sound sound play sound filename Plays a sound file It does not wait for the sound file to finish before moving to the next command It supports WAV AIFF and AU files plays the beep wav sample file sound play sound beep wav sound play sound and wait 256 Sound Extension NetLogo 4 1 2 User Manual sound play sound and wait filename Plays a sound file waiting for it to finish playing before moving to the next command lt supports WAV AIFF and AU files 7 plays the beep wav sample file waiting for it to finish before 7 playing boop wav sound play sound and walt beep wav sound play sound and wait boop wav sound play sound later so
414. operty over all of the VectorFeatures in the given dataset String values are compared using case sensitive lexicographic order as defined in the Java Documentation gis property maximum gis property maximum VectorDataset property name Reports the largest value for the given property over all of the VectorFeatures in the given dataset String values are compared using case sensitive lexicographic order as defined in the Java GIS Extension 287 NetLogo 4 1 2 User Manual Documentation gis apply coverage gis apply coverage VectorDataset property name patch variable Copies values from the given property of the VectorDataset s features to the given patch variable The dataset must be a polygon dataset points and lines are not supported For each patch it finds all VectorFeatures that intersect that patch Then if the property is a string property it computes the majority value by computing the total area of the patch covered by VectorFeatures having each possible value of the property then returning the value which represents the largest proportion of the patch area If the property is a numeric property it computes a weighted average of property values from all VectorFeatures which intersect the patch weighted by the proportion of the patch area they cover There are two exceptions to this default behavior e If a percentage of a patches area greater than the coverage maximum threshold is covered by a single VectorFeature then the prop
415. or the Java Virtual Machine such as Scala Clojure Groovy JRuby Jython etc Note The controlling facility is considered experimental It is likely to continue to change and grow Code you write now that uses it may need changes in order to continue to work in future NetLogo versions e Starting a Java VM for NetLogo e Example with GUI e Example headless e Example embedding e Conclusion The NetLogo API Specification contains further details Starting a Java VM for NetLogo NetLogo makes several assumptions about the Java VM that it is running in and therefore there are arguments which should be given to the VM at startup Recommended options for both GUI and headless Server Use server VM for highest performance Xmx1024m Use up to 1 gigabyte of memory for Java VM heap You may need to grow this number in order to run some models Additional recommended options for GUI only XX MaxPermSize 128m Prevent the VM from running out of memory when repeatedly compiling a model with very long code Djava ext dir Ignore any existing native libraries on the system This avoids conflicts with other versions of JOGL You may need to leave this option out or modify it to point to your native libraries if you are using Java VM extensions Djava library path lib Not needed on Mac or Windows may be needed on other OS s such as Linux Ensures NetLogo can find native libraries for JOGL and other extensions If you are
416. or y coordinate of the mouse in the 2D view The value is in terms of turtle coordinates so it might not be an integer If you want patch coordinates use round mouse xcor and round mouse ycor Note If the mouse is outside of the 2D view reports the value from the last time it was inside to make the mouse draw in red 1f mouse down ask patch mouse xcor mouse ycor set pcolor red move to move to agent The turtle sets its x and y coordinates to be the same as the given agent s If that agent is a patch the effect is to move the turtle to the center of that patch NetLogo Dictionary 377 NetLogo 4 1 2 User Manual move to turtle 5 5 turtle moves to same point as turtle 5 move to one of patches 7 turtle moves to the center of a random patch move to max one of turtles size 7 turtle moves to same point as biggest turtle Note that the turtle s heading is unaltered You may want to use the face command first to orient the turtle in the direction of motion See also setxy movie cancel movie cancel Cancels the current movie movie close movie close Stops the recording of the current movie movie grab view movie grab interface movie grab view movie grab interface Adds an image of the current view or the interface panel to the current movie 7 make a 20 step movie of the current view setup movie start out mov repeat 20 movie grab view go movie close movie set fram
417. order Deleting Select the element or elements you want to delete then press the Delete button on the Interface Toolbar You may also delete an element by control clicking Macintosh or right clicking other systems it and choosing Delete from the popup menu If you use this latter method it is not necessary to select the element first To learn more about the different kinds of interface elements refer to the chart below Chart Interface Toolbar Icon amp Name Description a Button Buttons can be either once only buttons or forever buttons When you click on a once button it executes its instructions once The forever button executes the instructions over and over until you click on the button again to stop the action If you have assigned an action key to the button pressing the corresponding keyboard key will act just like a button press when the button is in focus Buttons with action keys have a letter in the upper right corner of the button to show what the action key is If the input cursor is in another interface element such as the Command Center pressing the action key won t trigger the button The letter in the upper right hand corner of the button will be dimmed in this situation To enable action keys click in the white background of the Interface tab SEE slider Sliders are global variables which are accessible by all agents They are used in models as a quick way to change a variable without having to recode th
418. order will appear around the element to indicate that it is selected Selecting multiple items You can select multiple interface elements at the same time by including them in the rectangle you drag If multiple elements are selected one of them is the key item which means that if you use the Edit or Delete buttons on the Interface Toolbar only the key item is affected The key item is indicated by a darker gray border than the other items 76 Interface Guide NetLogo 4 1 2 User Manual Unselecting To unselect all interface elements click the mouse on the white background of the Interface tab To unselect an individual element control click Macintosh or right click other systems the element and choose Unselect from the popup menu Editing To change the characteristics of an interface element select the element then press the Edit button on the Interface Toolbar You may also double click the element once it is selected A third way to edit an element is to control click Macintosh or right click other systems it and choose Edit from the popup menu If you use this last method it is not necessary to select the element first Moving Select the interface element then drag it with your mouse to its new location If you hold down the shift key while dragging the element will move only straight up and down or straight left and right Resizing Select the interface element then drag the black handles in the selection b
419. ordinate systems only the following projections are supported Albers_Conic_Equal_Area Lambert Conformal Conic 2SP Polyconic Lambert Azimuthal Equal Area Mercator 1SP Robinson Azimuthal Equidistant Miller Stereographic Cylindrical Equal Area Oblique Mercator Transverse Mercatpr Equidistant Conic hotine oblique mercator Gnomonic Orthographic See remotesensing org for a complete list of WKT projections and their parameters gis set coordinate system gis set coordinate system system Sets the global projection used for projecting or re projecting GIS data as it is loaded The system must be either a string in Well Known Text WKT format or a NetLogo list that consists of WKT converted to a list by moving each keyword inside its associated brackets and putting quotes around it The latter is preferred because it makes the code much more readable GIS Extension 283 NetLogo 4 1 2 User Manual The same limitations on WKT support apply as described above in the documentation for load coordinate system Dataset Primitives gis load dataset gis load dataset file Loads the given data file re projecting the data as necessary if a global projection is defined and if the data file itself has an associated prj file then reports the resulting dataset If no prj file is present then 1oad dataset assumes that the projection of the data being loaded is the same as the current global coordinate system Relative paths are re
420. ou got a brief introduction to what it s like to interact with a NetLogo model This section will go into more depth about the features that are available while you re exploring the models in the Models Library Throughout all of the tutorials we ll be asking you to make predictions about what the effects of making changes to the models will be Keep in mind that the effects are often surprising We think these surprises are exciting and provide excellent opportunities for learning Some people have found it helpful to print out the tutorials in order to work through them When the tutorials are printed out there s more room on your computer screen for the NetLogo model you re looking at Sample Model Wolf Sheep Predation We ll open one of the Sample Models and explore it in detail Let s try a biology model Wolf Sheep Predation a predator prey population model e Open the Models Library from the File menu NetLogo MIES Edit Tools Zoon a New 3N tl 0 3 Open Models Library 3M 3 Save 3S E Save AS Save As Applet Print dE P e Choose Wolf Sheep Predation from the Biology section and press Open The Interface tab will fill up with lots of buttons switches sliders and monitors These interface elements allow you to interact with the model Buttons are blue they set up start and stop the model Sliders and switches are green they alter model settings Monitors and plots are beige they display dat
421. ouse button e f there is another turtle close to the red turtle you ll see more than one turtle listed at the bottom of the menu Move your mouse over the turtle selections notice when your mouse highlights a turtle menu item that turtle is highlighted in the view Select inspect turtle from the sub menu for the red turtle A turtle monitor for that car will appear 46 Tutorial 2 Commands NetLogo 4 1 2 User Manual 22 819848429529475 turtles false up 1649588621167962 The mini view at the top of the agent monitor will always stay centered this agent You can zoom the view in and out using the slider below the view and you can watch this turtle in the main view by pressing the watch me button Taking a closer look at this turtle monitor we can see all of the variables that belong to the red car A variable is a place that holds a value that can be changed Remember when it was mentioned that all colors are represented in the computer as numbers The same is true for the agents For example every turtle has an ID number we call its who number Let s take a closer look at the turtle monitor Tutorial 2 Commands 47 NetLogo 4 1 2 User Manual What is this turtle s who number What color is this turtle What shape is this turtle This turtle monitor is showing a turtle who that has a who number of 0 a color of 15 red see above chart and the shape of a car There are two other
422. ow count cats here gt 5 420 NetLogo Dictionary NetLogo 4 1 2 User Manual turtles on lt breeds gt on turtles on agent turtles on agentset lt breeds gt on agent lt breeds gt on agentset Reports an agentset containing all the turtles that are on the given patch or patches or standing on the same patch as the given turtle or turtles ask turtles if not any turtles on patch ahead 1 fa 1 ask turtles if not any turtles on neighbors die of loneliness If the name of a breed is substituted for turtles then only turtles of that breed are included turtles own lt breeds gt own turtles own var7 lt breeds gt own var7 The turtles own keyword like the globals breed lt breeds gt own and patches own keywords can only be used at the beginning of a program before any function definitions It defines the variables belonging to each turtle If you specify a breed instead of turtles only turtles of that breed have the listed variables More than one turtle breed may list the same variable breed cats cat breed dogs dog breed hamsters hamster turtles own eyes legs 7 applies to all breeds cats own fur kittens hamsters own fur cage dogs own hair puppies See also globals patches own breed lt breeds gt own type type value Prints value in the Command Center not followed by a carriage return unlike print and show The lack of a carriage r
423. p e How come NetLogo won t start up on my Linux machine e When try to start NetLogo on Windows get an error The JVM could not be started Help e Can run NetLogo from the command line without the GUI e Does NetLogo take advantage of multiple processors cores e Can distribute NetLogo model runs across a cluster or grid of computers e Is there any way to recover lost work if NetLogo crashes or freezes Usage e When move the speed slider all the way to the right why does my model seem to stop e Can use the mouse to paint in the view e How big can my model be How many turtles patches procedures buttons and so on can my model contain e Can use GIS data in NetLogo e Can I have more than one model open at a time e Can change the choices in a chooser on the fly e Can divide the code for my model up into several files Programming e How is the NetLogo language different from the StarLogo and StarLogoT languages How do convert my StarLogo or StarLogoT model to NetLogo e How does the NetLogo language differ from other Logos e How come my model from an earlier NetLogo doesn t work right e Why does my code have strange characters in it e How do take the negative of a number e My turtle moved forward 1 but it s still on the same patch Why e How do keep my turtles on patch centers e patch ahead 1 is reporting the same patch my turtle is already standing on Why e How do give my
424. p command random seed 0 App app command setup App app command repeat 50 go println App app report burned trees 200 Earth Science Fire nlogo Controlling Guide NetLogo 4 1 2 User Manual def wait block gt Unit EventQueue invokeAndWait new Runnable def run block In order to compile and run this Net Logo jar from the NetLogo distribution must be in the classpath In addition the 1ib directory also from the NetLogo distribution must be in same location it contains additional libraries used by Net Logo jar If you are using Scala you ll need to make sure you are using exactly the right version of Scala In order to run NetLogo in the same class loader with your own Scala code you must use the specific Scala build dated 2009 04 16 revision r17517 available here scala 2 8 0 r17517 zip We apologize for the inconvenience of requiring this particular Scala version in a future version of NetLogo we plan to require the final released version of Scala 2 8 0 instead once it becomes available Note that if you are a JVM wizard you may actually be able to run your own Scala code using a different Scala version than NetLogo requires by using the two Scala versions in different class loaders At least we don t know of a reason why this wouldn t work Note the use of EventQueue invokeAndWait to ensure that a method is called from the right thread This is becau
425. pened between ticks but it didn t get rid of the intermediate updates You had to use no display and display to lock them out We still support continuous updates They are the default when you start up NetLogo But most Models Library models now use tick based updates With tick based updates updates happen only when the tick counter advances The display command can be used to force additional updates see below The advantages of tick based updates as we see them are as follows 1 Consistent predictable view update behavior which does not vary from computer to computer or from run to run 2 Intermediate updates can confuse the user of your model by letting them see things they aren t supposed to see which may be misleading 3 Increased speed Updating the view takes time so if one update per tick is enough then enforcing than there is only one update per tick will make your model faster 4 Instead of having a force view update checkbox in every button like in NetLogo 3 1 we only need one choice which applies to the entire model 146 Transition Guide NetLogo 4 1 2 User Manual 5 Using the speed slider to slow down a model now just inserts pauses between ticks So with tick based updates setup buttons are no longer affected by the speed slider This was a real annoyance with the old speed slider The annoyance persists for models that use continuous updates though As mentioned above most models in our Models Library
426. period 7 a linear extrapolation of the next item in the list print matrix forecast linear growth 20 25 28 32 35 39 gt 42 733333333333334 20 619047619047638 3 6857142857142824 0 9953743395474031 These results tell us 5 the next predicted value is roughly 42 7333 7 the linear trend line is given by Y 20 6190 3 6857 t 7 Y grows by approximately 3 6857 units each period 77 the R 2 value is roughly 0 9954 a good fit matrix forecast compound growth matrix forecast compound growth data list Reports a four element list of the form forecast constant growth proportion R2 Whereas matrix forecast linear growth assumes growth by a constant absolute amount each period matrix forecast compound growth assumes that Y grows by a constant proportion each period The constant and growth proportion are the parameters of the trend line Y constant growth proportiont 250 Matrix Extension NetLogo 4 1 2 User Manual Note that the growth proportion is typically interpreted as growth proportion 1 0 growth rate Therefore if matrix forecast compound growth returns a growth proportion of 1 10 that implies that Y grows by 1 10 1 0 10 each period Note that if growth is negative matrix forecast compound growth will return a growth proportion of less than one E g a growth proportion of 0 90 implies a growth rate of 10 NOTE The compound growth forecast is achieved by taking the In of Y See
427. pment tips Instantiation Your class manager is instantiated at the time a model using the extension is loaded Command and reporter objects are instantiated whenever NetLogo code is compiled that uses your commands and reporters Classpath Don t forget to include NetLogo jar in your class path when compiling This is the most common mistake made by new extension authors If the compiler can t find NetLogo jar you ll get error messages about classes in the org nlogo api package not being found Debugging extensions There are special NetLogo primitives to help you as you develop and debug your extension These are considered experimental and may be changed at a later date That s why they have 236 Extensions Guide NetLogo 4 1 2 User Manual underscores in their name eprint _ dump extensions prints information about loaded extensions eprint _ dump extension prims prints information about loaded extension primitives e_ reload extensions forces NetLogo to reload all extensions the next time you compile your model Without this command changes in your extension JAR will not take effect until you open a model or restart NetLogo Third party JARs If your extension depends on code stored in a separate JAR copy the extra JARs into the extension s directory Whenever an extension is imported NetLogo makes all the JARs in its folder available to the extension If you plan to distribute your extension to other NetLogo users m
428. polygon e An agentset whose spatial representation is the union of the representations of all of the agents it contains e A list containing of any of the items listed here including another list The spatial representation of such a list is the union of the spatial representations of its contents gis contained by GIS Extension 289 NetLogo 4 1 2 User Manual gis contained by x y Reports true if every point of xs spatial representation is also a part of ys spatial representation The objects x and y may be any one of e a VectorDataset in which case the object s spatial representation is the union of all the points lines or polygons the dataset contains e a VectorFeature in which case the object s spatial representation is defined by the point line or polygon the feature contains e A turtle in which case the spatial representation is a point e A link whose spatial representation is a line segment connecting the two points represented by the turiles the link is connecting e A patch whose spatial representation is a rectangular polygon e An agentset whose spatial representation is the union of the representations of all of the agents it contains e A list containing of any of the items listed here including another list The spatial representation of such a list is the union of the spatial representations of its contents gis have relationship gis have relationship x y relationship Reports true if the spatial
429. prints distance other end of endl of link O 1 See also link heading link set link set value link set value1 value Reports an agentset containing all of the links anywhere in any of the inputs The inputs may be individual links link agentsets nobody or lists or nested lists containing any of the above link set self link set my links of nodes with color red See also turtle set patch set link shapes link shapes Reports a list of strings containing all of the link shapes in the model New shapes can be created or imported from other models in the Link Shapes Editor show link shapes gt default links links Reports the agentset consisting of all links show count links 7 prints the number of links 370 NetLogo Dictionary NetLogo 4 1 2 User Manual links own lt link breeds gt own links own var7 lt link breeds gt own var The links own keyword like the globals breed lt breeds gt own turtles own and patches own keywords can only be used at the beginning of a program before any function definitions It defines the variables belonging to each link If you specify a breed instead of links only links of that breed have the listed variables More than one link breed may list the same variable undirected link breed sidewalks sidewalk directed link breed streets street links own traffic 7 applies to all breeds sidewalks own pedestrians streets
430. put in the list are Doubles not Integers All numbers used as NetLogo values must be of type Double even if they happen to have no fractional part e To access arguments use org nlogo api Argument s typesafe helper methods such as getDoubleValue e Throw org nlogo api ExtensionException to signal a NetLogo runtime error to the modeler A Command is just like a Reporter except that reporters implement Object report while commands implement void perform 2 Write a ClassManager Each extension must include in addition to any number of command and reporter classes a class that implements the interface org nlogo api ClassManager The ClassManager tells NetLogo which primitives are part of this extension In simple cases extend the abstract class org nlogo api DefaultClassManager which provides empty implementations of the methods from ClassManager that you aren t likely to need Here s the class manager for our example extension src SampleExtension java import org nlogo api public class SampleExtension extends DefaultClassManager public void load PrimitiveManager primitiveManager primitiveManager addPrimitive first n integers new IntegerList 232 Extensions Guide NetLogo 4 1 2 User Manual addPrimitive tells NetLogo that our reporter exists and what its name is 3 Write a Manifest The extension must also include a manifest The manifest is a text file which tells NetL
431. r If you want to stop your experiment before it s finished press the Abort button Any results generated so far will still be saved When all the runs have finished the experiment is complete Advanced usage Running from the command line It is possible to run BehaviorSpace experiments headless that is from the command line without any graphical user interface GUI This is useful for automating runs on a single machine or a cluster of machines No Java programming is required Experiment setups can be created in the GUI and then run later from the command line or if you prefer you can create or edit experiment setups directly using XML How to use it Run Java with the org nlogo headless Main class The Main main method supports these arguments e model lt path gt pathname of model to open required e setup file lt path gt read experiment setups from this file instead of the model file e experiment lt name gt name of experiment to run e table lt path gt pathname to send table output to or for standard output e spreadsheet lt path gt pathname to send table output to or for standard output e threads lt number gt use this many threads to do model runs in parallel or 1 to disable parallel runs defaults to one thread per processor e min pxcor lt number gt override world size setting in model file e max pxcor lt number gt override world size setting in m
432. r Minimum Increment Maximum min pxcor Ha max pxcor Value so Units optional _ vertical Cancel Cok Agent Monitors You can open agent monitors though the Tools Menu or by using the inspect command Agent monitors display both the values of all the variables for a particular agent and a mini view that displays the agent a small radius around it Interface Guide 85 NetLogo 4 1 2 User Manual You can zoom in or out using the slider beneath the view and you can wat ch the agent using the watch me button and 0 Below the slider the current values of the each agent variable is displayed You can enter new values directly into the fields on the right It will be as if for example the code set pcolor had been executed Below agent variable area there is a mini command center Rather that executing code as the observer or talking to all of the turtles patches or links the code entered in this command center is executed by only by this agent set pcolor blue ow You can close the agent monitors by clicking the box in the upper left corner or by press escape If you hold down shift while you click the box all open agent monitors will close or you can close all the 86 Interface Guide NetLogo 4 1 2 User Manual agent monitors using the Close All Monitors option in the Tools Menu Information Tab The Information tab provides an introduction to the model and an explanation of how t
433. r file Opens a dialog that allows the user to choose an existing file on the system It reports a string with the absolute file path or false if the user cancels file open user fil NetLogo Dictionary 423 NetLogo 4 1 2 User Manual Assumes the user will choose a file user new file user new file Opens a dialog that allows the user to choose a location and name of a new file to be created lt reports a string with the absolute file path or false if the user cancels file open user new fil Assumes the user will choose a file Note that this reporter doesn t actually create the file normally you would create the file using file open as in the example If the user chooses an existing file they will be asked if they wish to replace it or not but the the reporter itself doesn t cause the file to be replaced To do that you would use file delete user input user input value Reports the string that a user types into an entry field in a dialog with title value value may be of any type but is typically a string show user input What is your name user message user message value Opens a dialog with value displayed as the message value may be of any type but is typically a string user message word There are count turtles turtles user one of user one of value list of choices Opens a dialog with value displayed as the message and ist of choices displayed as a popup menu for the user to select fro
434. r to the 3D view in NetLogo 2D However there are a few more ways to control the observer You can set the point that the observer is facing by using face and facexyz which work the same way as the turtle commands the Observer turns so the center of the view is on the given point or the location of the given agent at the time it is called You can change the location of the Observer using setxyz The Observer will move to view the world as if standing on the given location the point the observer faces will stay the same For example create a new model and Observer will be located at 0 O 49 5 that is on the z axis 49 5 patch units away from the origin and the Observer is facing the origin 0 0 0 If you setxyz 0 49 5 0 the Observer will move so it is on the positive y axis but it will keep the origin at the center of the view You can also move the observer using the rotation primitives that will allow you to move the observer around the world as if on the surface of a sphere where the center is the location the Observer is facing You may notice from the above examples that the Observer is not constrained to be within the bounds of the world Custom Shapes You can load your own shapes using the load shapes 3d primitive which takes a text file as an input Once you have loaded the shapes into the model you can use them just like the built in shapes Note that a 2D shape of the same name must exist as well You can create the 2D shape in the
435. r what license is NetLogo released Is the source code available e Do you offer any workshops or other training opportunities for NetLogo e Are there any NetLogo textbooks e Is NetLogo available in a Spanish version Chinese version your language here version etc e Is NetLogo compiled or interpreted e Has anyone built a model of lt x gt e Are NetLogo models runs scientifically reproducible e Will NetLogo and NetLogo 3D remain separate applications Downloading e Can have multiple versions of NetLogo installed at the same time e I m on a UNIX system and can t untar the download Why e How do install NetLogo unattended e On Windows how do configure the Java installation that the without Java installer uses Applets e tried to run one of the applets on your site but it didn t work What should do e When running my model as an applet get the following error java lang OutOfMemoryError Java heap space e Can make my model available as an applet while keeping the code secret e Can a model saved as an applet use import world file open and other commands that read files e When tried loading my model as an applet get an error like java lang ClassFormatError Incompatible magic value Running e Can run NetLogo from a CD a network drive or a USB drive FAQ Frequently Asked Questions 299 NetLogo 4 1 2 User Manual e Why is NetLogo so much slower when unplug my Windows lapto
436. rantee due not only to the possibility of random hardware failure but also the possibility of human error in the design of your model NetLogo your Java VM your hardware and so on Will NetLogo and NetLogo 3D remain separate Although NetLogo 3D is now included in the NetLogo download it is still a separate application However the split is temporary Eventually a single unified application will support both 2D and 3D modeling We will be sure to design the 3D world support in such a way that it doesn t get in the way when you are building 2D models Models built in NetLogo 3D may require changes in order to run in the eventual unified application Downloading Can have multiple versions of NetLogo installed at the same time Yes When you install NetLogo the folder that is created contains has the version number in its name so multiple versions can coexist On Windows systems whichever version you installed last will be the version that opens when you double click a model file in Windows Explorer On Macs you can control what version opens via Get Info in the Finder I m on a UNIX system and can t untar the download Why Some of the files in the tarball have long pathnames too long for the standard tar format You must use the GNU version of tar instead or another program which understands the GNU tar extensions On some systems the GNU version of tar is available under the name gnutar You can find out if you are
437. rd since parallel runs progress independently of each other table format output may contain interleaved out of order results When you analyze your table data you may wish to sort it by run number first Spreadsheet format output is not affected by this issue since it is not written until the experiment completes or is aborted Fourth using all available processor cores may make your computer slow to use for other tasks while the experiment is running BehaviorSpace Guide 165 NetLogo 4 1 2 User Manual Fifth doing runs in parallel will multiply the experiment s memory requirements accordingly You may need to increase NetLogo s memory ceiling see this FAQ entry Observing runs After you complete the run options dialog another dialog will appear titled Running Experiment In this dialog you ll see a progress report of how many runs have been completed so far and how much time has passed If you entered any reporters for measuring the runs and if you left the Measure runs at every step box checked then you ll see a plot of how they vary over the course of each run You can also watch the runs in the main NetLogo window If the Running Experiment dialog is in the way just move it to a different place on the screen The view and plots will update as the model runs If you don t need to see them update then use the checkboxes in the Running Experiment dialog to turn the updating off This will make the experiment go faste
438. re white e 10 20 and so on are all so dark they appear black e 19 9 29 9 and so on are all so light they appear white Code Example The color chart was made in NetLogo with the Color Chart Example model If you use a number outside the O to 140 range NetLogo will repeatedly add or subtract 140 from the number until it is in the O to 140 range For example 25 is orange so 165 305 445 and so on are orange too and so are 115 255 395 etc This calculation is done automatically whenever you set the turtle variable color or the patch variable pcolor Should you need to perform this calculation in some other context use the wrap color primitive If you want a color that s not on the chart more can be found between the integers For example 26 5 is a shade of orange halfway between 26 and 27 This doesn t mean you can make any color in NetLogo the NetLogo color space is only a subset of all possible colors It contains only a fixed set of discrete hues one hue per row of the chart Starting from one of those hues you can either decrease its brightness darken it or decrease its saturation lighten it but you cannot decrease both brightness and saturation Also only the first digit after the decimal point is significant Thus color values are rounded down to the next 0 1 so for example there s no visible difference between 98 Programming Guide NetLogo 4 1 2 User Manual 26 5 and 26 52 or 26 58 Color primitives
439. re written simulations that can be used and modified These simulations address many content areas in the natural and social sciences including biology and medicine physics and chemistry mathematics and computer science and economics and social psychology Several model based inquiry curricula using NetLogo are currently under development NetLogo can also power a classroom participatory simulation tool called HubNet Through the use of networked computers or handheld devices such as Texas Instruments graphing calculators each student can control an agent in a simulation Follow this link for more information NetLogo is the next generation of the series of multi agent modeling languages that started with StarLogo It builds off the functionality of our product StarLogoT and adds significant new features and a redesigned language and user interface NetLogo runs on the Java virtual machine so it works on all major platforms Mac Windows Linux et al It is run as a standalone application or from the command line Models and HubNet activities can be run as Java applets in a web browser Features e System 4 Cross platform runs on Mac Windows Linux et al e Language Fully programmable Simple language structure Language is Logo dialect extended to support agents Mobile agents turtles move over a grid of stationary agents patches 4 Link agents connect turtles to make networks graphs and aggregates Large vocabulary of b
440. red in pixels of labels on agents Tick counter Y Show tick counter Tick counter label ticks Cancel Apply OK Notice that the settings are broken up into three groups There are world view and ticks counter settings World settings affect the properties of the world that the turtles live in changing them may require resetting the world View and tick counter settings only affect the appearance changing them will not affect the outcome of the model The world settings allow you to define the boundaries and topology of the world At the top of the left side of the world panel you can choose a location for the origin of the world either Center Corner Edge or Custom By default the world has a center configuration where 0 0 is at the center of the world and the user defines the number of patches from the center to the right and left boundaries and the number of patches from the center to the top and bottom boundaries For Interface Guide 79 NetLogo 4 1 2 User Manual Example If you set Max Pxcor 10 Min Pxcor will automatically be set to 10 thus there are 10 patches to the left of the origin and 10 patches to the right of patch 0 0 A Corner configuration allows the user to define the location of the origin as one of the corners of the world upper left upper right lower left or lower right Then you define the far boundary in the x and y directions For example if you choose to put the origin in the
441. reen 5 Of the view turn green end The models in the Models Library are full of other examples A good place to start looking is in the Code Examples section Usually the observer uses ask to ask all turtles all patches or all links to run commands You can also use ask to have an individual turtle patch or link run commands The reporters turtle patch link and patch at are useful for this technique For example to setup clear all EXE 3 make 3 turtles ask turtle 0 tell the first one fa 1 5 to go forward ask turtle 1 tell the second one set color green 5 to become green ask turtle 2 tell the third one rt 90 J SR 2a O Carn eight ask patch 2 2 7 ask the patch at 2 2 set pcolor blue 27 to become blue ask turtle 0 7 ask the first turtle ask patch at 1 0 7 to ask patch to the east set pcolor red j7 to become red ask turtle 0 tell the first turtle create link with turtle 1 make a link with the second ask link 0 1 tell the link between turtle 0 and 1 set color blue j to become blue end Every turtle created has a who number The first turtle created is number 0 the second turtle number 1 and so forth The turtle primitive reporter takes a who number as an input and reports the turtle with that who number The patch primitive reporter takes values for pxcor and pycor and reports the patch with those coordinates The Link primitive takes two i
442. relays and other devices The GoGo Extension for NetLogo provides simple primitives to communicate with a GoGo board GoGo Board a low cost robotics and data logging board A GoGo Board is an open source easy to build low cost general purpose serial interface board especially designed to be used in school and for educational projects It was created by Arnan Sipitakiat with the collaboration of Paulo Blikstein at the MIT Media Lab in 2001 and has been actively developed since then It is currently used in over 10 countries such as the United States China Thailand Brazil Portugal Mexico Malaysia and Egypt Up to 8 sensors i e temperature light pressure and 4 output devices i e motors light bulbs LEDs relays can be connected to the board simultaneously The board also has a connector for add on devices such as a small display or a wireless communication module Coupled to a serial Bluetooth dongle such as the logear or WCSC models instead of a serial cable it can be used as a wireless device as well Sensor and actuator toolkits NetLogo models can interact with the physical world in two ways First they can gather data from the environment This information can be used by the model to change or calibrate its behavior This data is gathered using electronic sensors which can measure a wide range of phenomena NetLogoLab and the GoGo Board Extension 261 NetLogo 4 1 2 User Manual temperature light touch see
443. rence Replace all will change all instances of the the find phrase in the search area with the replace phrase 90 Interface Guide NetLogo 4 1 2 User Manual To find a particular procedure definition in your code use the Procedures popup menu in the Procedures Toolbar The menu lists all procedures in alphabetical order The Shift Left Shift Right Comment and Uncomment items on the Edit menu are used in the procedures tab to change the indentation level of your code or add and remove semicolons which mark comments from sections of code For more information about writing procedures read Tutorial 3 Procedures and the Programming Guide Includes Menu When you add the __includes keyword to a model a menu to the right of the procedures menu appears This is the includes menu which lists all the NetLogo source files nls included in this file either nlogo or nls D Y Find Checl includes foo nls J You can click on the file names in the menu to open a new tab containing that file or you can open new files or files in the file system using the other New Source File and Open Source File respectively New Source File Open Source File Procedures w Includes w Once you ve opened new tabs you can navigate them similarly to the other tabs They are accessible from the Tabs menu and you can use the keyboard to move from tab to tab Command number on Mac Control number on
444. renderer not the Sun renderer Version 4 1 December 2009 e system NetLogo 3D is no longer a separate download but is still a separate application Java 5 or higher is now required NetLogo and its applets no longer support Mac OS X 10 2 Mac OS X 10 3 Windows 98 or Windows ME the Windows installer and launcher are new and should be compatible with more systems on Windows we now bundle Java 6 instead of Java 5 on 64 bit Linux 3D now works on Mac OS X the application now works with 64 bit Java though by default it still runs in 32 bit BehaviorSpace is now free and open source software under the LGPL e features BehaviorSpace is now multi threaded so runs happen in parallel 14 What s New NetLogo 4 1 2 User Manual Controlling API now supports embedding of models in a surrounding application automatic indenter for code in the Procedures tab Models Library dialog now offers searching 4 links turtles and the drawing may now be partially transparent RGB colors only 2D view only agent monitors now include a mini view centered on the agent extensions that use additional jars now work in applets the sound extension is now supported in applets new resize world and set patch size commands allow changing the dimensions of the patch grid applet web pages now include color coded Procedures tab contents new bitmap and QTJ QuickTime for Java extensions allow importing image and video data the Go
445. rently hidden i e invisible You can set this variable to make a turtle or link disappear or reappear NetLogo Dictionary 351 NetLogo 4 1 2 User Manual See also hide turtle show turtle hide link show link Example set hidden not hidden 5 if turtle was showing it hides and if it was hiding it reappears hide link hide link The link makes itself invisible Note This command is equivalent to setting the link variable hidden to true See also show link hide turtle ht hide turtle x The turtle makes itself invisible Note This command is equivalent to setting the turtle variable hidden to true See also show turtle histogram histogram list Histograms the values in the given list Draws a histogram showing the frequency distribution of the values in the list The heights of the bars in the histogram represent the numbers of values in each subrange Before the histogram is drawn first any previous points drawn by the current plot pen are removed Any non numeric values in the list are ignored The histogram is drawn on the current plot using the current plot pen and pen color Use set plot x range to control the range of values to be histogrammed and set the pen interval either directly with set plot pen interval or indirectly via set histogram num bars to control how many bars that range is split up into Be sure that if you want the histogram drawn with bars that the current pen is in bar
446. reporter if there are not number agents with that value then the agents with the second lowest value are found and so on At the end if there is a tie that would make the resulting agentset too large the tie is broken randomly 77 assume the world is 11 x 11 show min n of 5 patches pxcor 7 shows 5 patches with pxcor min pxcor show min n of 5 patches with pycor 0 pxcor 7 shows an agentset containing 5 patch 5 0 patch 4 0 patch 3 0 patch 2 0 patch 1 0 See also min one of with min min one of min one of agentset reporter Reports a random agent in the agentset that reports the lowest value for the given reporter If there is a tie this command reports one random agent that meets the condition If you want all such agents use with min instead show min one of turtles xcor ycor reports the first turtle with the smallest sum of coordinates NetLogo Dictionary 375 NetLogo 4 1 2 User Manual See also with min min n of min pxcor min pycor min pxcor min pycor These reporters give the minimum x coordinate and minimum y coordinate respectively for patches which determines the size of the world Unlike in older versions of NetLogo the origin does not have to be at the center of the world However the minimum x and y coordinates must be less than or equal to zero Note You can set the size of the world only by editing the view these are reporters which cannot be set
447. res new experimental includes keyword allows splitting model code into multiple source files color variables can now contain either a NetLogo color or an RGB color as a list of three numbers programmable slider bounds you can now use any NetLogo reporter as the min max or increment of a slider exporting the world now includes all plot data and when you import a world the contents of plots are restored the sound extension can now play audio files in addition to MIDI sounds notes monitors and output areas now have editable font size the color of text in notes is now editable and a note s background may now optionally be transparent Snap to Grid in Interface tab added menu items and F1 keyboard shortcut for quickly accessing NetLogo Dictionary sliders may now be vertical or horizontal model files with unsaved changes are auto saved to a temporary files directory in case of freezes crashes HubNet clients are much easier to edit now the client is no longer a separate model Mathematica NetLogo link provides a real time link between Mathematica and NetLogo for controlling model runs and visualizing and analyzing results after the fact or in real time the run and runresult primitives are now drastically faster when called repeatedly on the same string internally lists are now represented as linked lists not arrays plotting is now supported when running headless e language changes 4 4 4 4 o the ask command now always ru
448. riable It indicates the second endpoint turtle of a link For directed links this will always be the destination for undirected links it will always be the turtle with the higher who number You cannot set end2 Ore 2 ask turtle 1 create link with turtle 0 ask links show end2 shows turtle 1 error message error message Reports a string describing the error that was suppressed by carefully This reporter can only be used in the second block of a carefully command See also carefully every every number commands Runs the given commands only if it s been more than number seconds since the last time this agent ran them in this context Otherwise the commands are skipped By itself every doesn t make commands run over and over again You need to use every inside a loop or inside a forever button if you want the commands run over and over again every only limits how often the commands run Above in this context means during the same ask or button press or command typed in the Command Center So it doesn t make sense to write ask turtles every 0 5 because when the ask finishes the turtles will all discard their timers for the every The correct usage is shown below every 0 5 ask turtles fd 1 twice a second the turtles will move forward 1 every 2 set index index 1 340 NetLogo Dictionary NetLogo 4 1 2 User Manual 7 every 2 seconds index is incremented See also wait
449. ributed random number with the mean and in the case of the normal distribution the standard deviation random exponential reports an exponentially distributed random floating point number It is equivalentto mean In random float 1 0 random gamma reports a gamma distributed random floating point number as controlled by the floating point alpha and lambda parameters Both inputs must be greater than zero Note for results with a given mean and variance use inputs as follows alpha mean mean variance lambda 1 variance mean random normal reports a normally distributed random floating point number random poisson reports a Poisson distributed random integer 396 NetLogo Dictionary NetLogo 4 1 2 User Manual show random exponential 2 7 prints an exponentially distributed random floating 7 point number with a mean of 2 show random normal 10 1 5 2 7 prints a normally distributed random floating point 7 number with a mean of 10 1 and a standard deviation ee OE Fee show random poisson 3 4 5 prints a Poisson distributed random integer with a mean of 3 4 random pxcor random pycor random pxcor random pycor Reports a random integer ranging from min pxcor or y to max pxcor or y inclusive ask turtles 7 move each turtle to the center of a random patch setxy random pxcor random pycor See also random xcor random ycor random seed random seed number Sets the seed of the pseud
450. rimenting with and expanding this model if you d like experimenting with different variables and behaviors for the agents Alternatively you may want to revisit the first model in the tutorial Wolf Sheep Predation This is the model you used in Tutorial 1 In the Wolf Sheep Predation model you saw sheep move around consume resources that are replenished occasionally grass reproduce under certain conditions and die if they ran out of resources But that model had another type of creature moving around wolves The addition of wolves requires some additional procedures and some new primitives Wolves and sheep are two different breeds of turtle To see how to use breeds study Wolf Sheep Predation Alternatively you can look at other models including the many models in the Code Examples section of the Models Library or even go ahead and build your own model You don t even have to model anything It can be interesting just to watch patches and turtles forming patterns to try to create a game to play or whatever Tutorial 43 Procedures 69 NetLogo 4 1 2 User Manual Hopefully you have learned some things both in terms of the NetLogo language and about how to go about building a model The entire set of procedures that was created above is shown below Appendix Complete code The complete model is also available in NetLogo s Models Library in the Code Examples section It s called Tutorial 3 Notice that this listing is fu
451. rld will grow in increments of two adding one to the maximum and subtracting one from the minimum If one of the edges is set to O the world will grow by one in the other direction to keep the origin along the edge If the origin is at a custom location the black arrows will be disabled There are a number of settings associated with the Views There are a few ways of changing the settings by using the control strip along the top edge of the View or by editing the 2D View as 78 Interface Guide NetLogo 4 1 2 User Manual described in the Working With Interface Elements section above or pressing the Settings button in the toolbar Notice that the control strip in the 3D View combines the ticks counter from the 2D view control strip and the controls from the right portion of the interface toolbar dd M view updates ticks O Tr r Settings y continuous oo normal speed Here are the settings for the View accessible by editing the View or by pressing the Settings button in the Interface Toolbar Model Settings World e 16 16 16 16 Location of origin Center 4 j pxcor minimum x coordinate for patches max pxcor 16 maximum x coordinate for patches 1 pycor minimum y coordinate for patches 16 16 16 16 e max pycor 16 Torus 33 x 33 maximum y coordinate for patches Y World wraps horizontally Y World wraps vertically View Patch size 13 Font size 10 measu
452. rly you can set the shape variable of links Assuming there is a link shape called road in this model observer gt crt 5 create links with other turtles turtles gt fd 5 links gt set shape road The set default shape command is also useful for assigning shapes to turtles and links 160 Shapes Editor Guide BehaviorSpace Guide This guide has three parts e What is BehaviorSpace A general description of the tool including the ideas and principles behind it e How It Works Walks you through how to use the tool and highlights its most commonly used features e Advanced Usage How to use BehaviorSpace from the command line or from your own Java code e Source Code About the source code for BehaviorSpace What is BehaviorSpace BehaviorSpace is a software tool integrated with NetLogo that allows you to perform experiments with models BehaviorSpace runs a model many times systematically varying the model s settings and recording the results of each model run This process is sometimes called parameter sweeping It lets you explore the model s space of possible behaviors and determine which combinations of settings cause the behaviors of interest If your computer has multiple processor cores then by default model runs will happen in parallel one per core BehaviorSpace is free and open source software Why BehaviorSpace The need for this type of experiment is revealed by the following observations Mo
453. rovide users with a highly interactive self documenting work flow that neither can provide alone Mathematica includes many of the tools that agent based modelers rely on throughout the research process advanced import capabilities statistical functions data visualization and document creation With the NetLogo Mathematica link you can run all of these tools side by side with NetLogo Because all Mathematica documents or notebooks contain comments code images annotations and interactive objects the integration of NetLogo and Mathematica provides a more complete solution for complex model exploration for students and researchers alike The basic functionality of the link is much like the NetLogo Controlling API you can load models execute commands and report back data from NetLogo Unlike the Controlling API which is based on Java all interactions with the link are interpreted making it ideal not only for rapidly designing custom BehaviorSpace like experiments but also as a companion to NetLogo in debugging your model For more information about Mathematica please visit the Wolfram Research web site What can I do with it Here are a few examples of what you can do with the Mathematica NetLogo link e Analyze your model in real time with seamless two way data conversion e Develop high quality custom visualizations of model data e Collect detailed simulation data across large multi dimensional parameter spaces e Rapidly
454. rst loaded to startup setup end stop stop This agent exits immediately from the enclosing procedure ask or ask like construct e g crt hatch sprout Only the current procedure stops not all execution for the agent if not any turtles stop exits if there are no more turtles Note stop can be used to stop a forever button If the forever button directly calls a procedure then when that procedure stops the button stops In a turtle or patch forever button the button won t stop until every turtle or patch stops a single turtle or patch doesn t have the power to stop the whole button subject subject Reports the turile or patch that the observer is currently watching following or riding Reports nobogy if there is no such turtle or patch See also watch follow ride 414 NetLogo Dictionary NetLogo 4 1 2 User Manual sublist substring sublist list position1 position2 substring string position position2 Reports just a section of the given list or string ranging between the first position inclusive and the second position exclusive Note The positions are numbered beginning with 0 not with 1 show sublist 99 88 77 66 1 3 gt 88 77 show substring apartment 1 5 gt part subtract headings subtract headings heading1 heading2 Computes the difference between the given headings that is the number of degrees in the smallest angle by which heading2 could be rotated
455. rtain operations are especially efficient namely operations at the front of the list The first but first and fput reporters are all very fast they take the same amount of time to run no matter how long the list is So if you re building up a list by adding items to it one at a time it s much faster to use fput than 1put If that causes your list to end up backwards from how you wanted it you can always use reverse to reverse the list once you re done building it The length reporter is also fast NetLogo always keeps track of how long every list is so it never needs to actually measure Examples of reporters which are slower on longer lists include item lput but last last and one of Math All numbers in NetLogo are stored internally as double precision floating point numbers as defined in the IEEE 754 standard They are 64 bit numbers consisting of one sign bit an 11 bit exponent and a 52 bit mantissa See the IEEE 754 standard for details An integer in NetLogo is simply a number that happens to have no fractional part No distinction is made between 3 and 3 0 they are the same number This is the same as how most people use numbers in everyday contexts but different from some programming languages Some languages treat integers and floating point numbers as distinct types Integers are always printed by NetLogo without the trailing 0 show 1 5 1 5 observer 3 If a number with a fractional part is supplied i
456. rty name Reports the value of the property with the given name for the given VectorDataset The reported value may be a number a string or a boolean value depending on the type of the field in the underlying data file For shapefiles values from dBase CHARACTER and DATE fields are returned as strings values from NUMBER and FLOAT fields are returned as numbers and values from LOGICAL fields are returned as boolean values MEMO fields are not supported DATE values are converted to strings using ISO 8601 format Y YYY MM DD gis find features gis find features VectorDataset property name string Reports a list of all VectorFeatures in the given dataset whose value for the property property name matches the given string Value comparison is not case sensitive and the wildcard character will match any number of occurrences including zero of any character gis find one feature 286 GIS Extension NetLogo 4 1 2 User Manual gis find one feature VectorDataset property name string Reports the first VectorFeature in the dataset whose value for the property property name matches the given string Value comparison is not case sensitive and the wildcard character will match any number of occurrences including zero of any character Features are searched in the order that they appear in the data file that was the source of the dataset and searching stops as soon as a match is found Reports nobody if no ma
457. s HubNet Guide 187 NetLogo 4 1 2 User Manual that are available for Computer HubNet The Calculator HubNet extension is available from Inquire Learning LLC in collaboration with Texas Instruments Inquire Learning also offers support curricular materials and professional development for the Calculator HubNet system For more information on the Tl Navigator system itself please visit the Texas Instruments web site at http education ti com navigator For more information on the Calculator HubNet extension for TI Navigator please contact Inquire Learning at calc hubnet inquirelearning com or visit http www inquirelearning com calc hubnet html Teacher workshops For information on upcoming workshops and NetLogo and HubNet use in the classroom please contact us at feedback ccl northwestern edu HubNet Authoring Guide To learn about authoring or modifying HubNet activities see the HubNet Authoring Guide Getting help If you have any questions about Computer HubNet or Calculator HubNet or need help getting started please email us at feedback ccl northwestern edu 188 HubNet Guide HubNet Authoring Guide This guide presents information you will need to understand and modify the code of existing HubNet Activities as well as write your own HubNet activities This guide assumes you are familiar with running HubNet activities basic NetLogo code and NetLogo interface elements for more general information about HubNet see th
458. s and NetLogo colors using approximate hsb and approximate rgb from RGB HSB to NetLogo colors and extract hsb and extract rgb in the opposite direction You can use rgb to generate rgb lists and hsb to convert from an HSB color to RGB Since many colors are missing from the NetLogo color space approximate hsb and approximate rab often can t give you the exact color you ask for but they try to come as close as possible You can change any turtle from it s existing NetLogo color to a half transparent version of that color using set color lput 125 extract rgb color Code Examples HSB and RGB Example lets you experiment with the HSB and RGB color systems Transparency Example Programming Guide 99 NetLogo 4 1 2 User Manual Color Swatches dialog The Color Swatches dialog helps you experiment with and choose colors Open it by choosing Color Swatches on the Tools Menu 606 Color Swatches gray 5 8 7 white 9 9999 A Praviaw 9 9999 red 15 19 19 9999 orange 25 29 29 9999 brown 35 39 39 9999 yellow 45 green 55 lime 65 turquoise 75 cyan 85 as as 9999 2 E 2 amp amp Ra a a o lo g E sky 95 so 99 9999 blue 105 108 109 109 9999 wiolet 115 118 119 119 9999 magenta 125 128 129 129 9999 pink 135 138 139 139 9999 Copy selected color black M Numbers 10 0 50 0 1 Increment When you click on a color swatch or a color button th
459. s and some agentset operators like with and in points are infix All commands and reporters both primitive and user defined take a fixed number of inputs by default That s why the language can be parsed though there is no punctuation to separate or terminate commands and or inputs Some primitives are variadic that is may optionally take a different number of inputs than the default parentheses are used to indicate this e g list 1 2 3 since the list primitive only takes two inputs by default Parentheses are also used to override the default operator precedence e g 1 2 3 asin other programming languages Sometimes an input to a primitive is a command block zero or more commands inside square brackets or a reporter block a single reporter expression inside square brackets User defined procedures may not take a command or reporter block as input Operator precedences are as follows high to low e with at points in radius in cone e all other primitives and user defined procedures e A ex mod Compared to other Logos There is no agreed upon standard definition of Logo itis a loose family of languages We believe that NetLogo has enough in common with other Logos to earn the Logo name Still NetLogo differs in some respects from most other Logos The most important differences are as follows Surface differences e The precedence of mathematical operators is different Infix math operators like
460. s or pairs The first element in the pair is the key and the second element is the value table get table get table key Reports the value that key is mapped to in the table Causes an error if there is no entry for the key table has key table has key table key Reports true if key has an entry in table table keys Array and Table Extensions 241 NetLogo 4 1 2 User Manual table keys table Reports a list of all the keys in table table length table length table Reports the number of entries in table table make table make Reports a new empty table table put table put table key value Maps key to value in table If an entry already exists in the table for the given key it is replaced table remove table remove table key Removes the mapping in table for key table to list table to list table Reports a list with the content of table The list will be a list of two element lists or pairs The first element in the pair is the key and the second element is the value 242 Array and Table Extensions Matrix Extension The Matrix extension adds a new matrix data structure to NetLogo similar to how the the array table data structures were added by their respective extensions When to use A matrix is a 2 dimensional array containing only numeric data Although it can be used to store numbers in the same way as a list of lists or an array of arrays the primary reason to use the matrix data type is to take advant
461. s you should then go back Tutorial 3 Procedures 53 NetLogo 4 1 2 User Manual over the directions to see if there is any step you might have missed Making the go button Now make a button called go Follow the same steps you used to make the setup button except e For Commands enter go instead of setup e Check the forever checkbox in the edit dialog a A setup 890 Button Agent s Observer HH M Forever Commands go Display name Action key Cancel The forever checkbox makes the button stay down once pressed so its commands run over and over again not just once e Then add a go procedure to the Procedures tab Lo go move turtles end But what ismove turtles ls it a primitive in other words built in to NetLogo like clear a11 is No it s another procedure that you re about to add So far you have introduced two procedures that you added yourself setup and go e Add the move turtles procedure after the goprocedure EO do 54 Tutorial 3 Procedures NetLogo 4 1 2 User Manual move turtles end to move turtles ask turtles right random 360 forward 1 end Note there are no spaces around the dash in move turtles In Tutorial 2 we used red 2 with spaces in order to subtract two numbers but here we want move turt les without spaces The combines move and turtles into a single name Here is what each command in the move t
462. s Monitor ation P Turtle Monitor ser c Patch Monitor Hide Command Center 3D View Shapes Editor BehaviorSpace onti tel Our model will have a population of wolves and a population of sheep Let s start with the sheep First create a Stock that holds a population of Sheep e Press the Stock button in the toolbar CE O variable Flow Link 176 System Dynamics Guide NetLogo 4 1 2 User Manual e Click in the diagram area You see a Stock with a red question mark in the middle e Double click the Stock to edit e Name the stock sheep e Set the initial value to 100 e Deselect the Allow Negative Values checkbox It doesn t make sense to have negative sheep e06 Name sheep Initial value 100 Allow negative values Our sheep population can increase if new sheep are born To add this to our diagram we create a Flow into the stock of sheep e Click on the Flow button in the toolbar and press the mouse button in an empty area to the left of the sheep Stock Drag the Flow to the right until it connects to the sheep Stock and let go e Edit the Flow and name it sheep births e For now enter a constant such as 1 into the Expression field The number of sheep born during a period of time depends on the number of sheep that are alive more sheep means more reproduction e Draw a Link from the sheep Stock to the sheep births Flow The rate of sheep births al
463. s by Sean Luke The copyright for that code is as follows Copyright c 2003 by Sean Luke Portions copyright c 1993 by Michael Lecuyer All rights reserved Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met e Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer e Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided 4 Copyright and License Information NetLogo 4 1 2 User Manual with the distribution e Neither the name of the copyright owners their employers nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE COPYRIGHT OWNERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEOR
464. s hereby grant you a world wide royalty free non exclusive license subject to third party intellectual property claims to use reproduce modify display perform sublicense and distribute all or any portion of the source code or binary form of this software or related data with or without modifications or as part of a larger work and under patents now or hereafter owned or controlled by the Authors to make have made use and sell Utilize all or any portion of the source code or binary form of this software or related data but solely to the extent that any such patent is reasonably necessary to enable you to Utilize all or any portion of the source code or binary form of this software or related data and not to any greater extent that may be necessary to Utilize further modifications or combinations In return you agree to the following conditions If you redistribute all or any portion of the source code of this software or related data it must retain the above copyright notice and this license and disclaimer If you redistribute all or any portion of this code in binary form you must include the above copyright notice and this license and disclaimer in the documentation and or other materials provided with the distribution and must indicate the use of this software in a prominent publically accessible location of the larger work You must not use the Authors s names to endorse or promote products derived from this software without the
465. s interrupted in the middle of whatever it was doing you may get unexpected results if you try to continue running the model without first pressing setup to start the model run over Globals Monitor Displays the values of all global variables 74 Turtle Monitor Displays the values of all of the variables in a particular turtle You can an also edit the values of the turtle s variables and issue commands to he turtle You can also open a turtle monitor via the View see the View Patch Monitor Displays the values of all of the variables in a particular patch You can an also edit the values of the patch s variables and issue commands to Interface Guide NetLogo 4 1 2 User Manual he patch You can also open a patch monitor via the View see the View section below Link Monitor Displays the values of all of the variables in a particular link You can an also edit the values of the link s variables and issue commands to he link na can also open a link monitor via the View see the View Close All Agent Closes all open agent monitor windows Monitors Hide Show Makes the command center visible or invisible Note that the command Command Center center can also be shown or hidden or resized with the mouse 3D View Opens the 3D view See the Views section for more information Color Swatches Opens the Color Swatches See the Color Section of the Programming Guide for details Turtle Shapes Draw turtle s
466. s store dataset primitive There is currently no way to distinguish positive area shell polygons from negative area hole polygons or to determine which holes are associated with which shells GIS primitives Coordinate System Primitives set transformation set transformation ds set world envelope set world envelope ds world envelope envelope of envelope union of load coordinate system set coordinate system Dataset Primitives load dataset store dataset type of patch dataset turtle dataset link dataset VectorDataset Primitives shape type of property names feature list of vertex lists of centroid of location of property value find features find one feature find less than find greater than find range property minimum property maximum apply coverage coverage minimum threshold set coverage minimum threshold coverage maximum threshold set coverage maximum threshold intersects contains contained by have relationship relationship of RasterDataset Primitives width of height of raster value set raster value minimum of maximum of sampling method of set sampling method raster sample raster world envelope create raster resample convolve apply raster Drawing Primitives drawing color set drawing color draw fill paint 280 GIS Extension NetLogo 4 1 2 User Manual Coordinate System Primitives gis set transformation gis set transformation gis envelope netlogo envelope Defines a mapping between GIS coordinates and NetLogo coordinates The
467. s were sometimes rendered incorrecily in some sizes fixed bug where saved applets that used extensions didn t load additional jars used by the extension fixed bug where closing a browser window containing applet could cause a spurious error dialog to appear fixed bug where the 1ink primitive could fail when given a non existent turtle number fixed bug where the mini views in agent inspectors could have incorrect appearance with very small patch grids fixed bug where the context menu on the view in applets contained some non working items fixed bug where movie primitives didn t fail gracefully when used in parallel BehaviorSpace runs fixed bug where changing a plot pen s mode on the fly didn t refresh the plot fixed bug causing models using links not to work in the NetLogo Logging application fixed bug where new seed primitive could theoretically return duplicate seeds in a parallel BehaviorSpace experiment fixed sound extension bug where the wrong instrument sometimes played fixed bug where using follow could cause turtle labels not to be drawn fixed bug where the remove primitive didn t fail gracefully if given incorrect input fixed HubNet bug where the drawing layer wasn t always mirrored to clients fixed GIS extension bug where clipping of coordinates to user s GIS envelope was causing errors saving link datasets fixed bitmap extension so it works in applets on Mac OS X always force use of the Quartz
468. s4 set pcolor red turns the four neighboring patches red lt breed gt neighbors link neighbors lt breed gt neighbors link neighbors Reports the agentset of all turtles found at the other end of undirected links connected to this turtle crt 3 ask turtle 0 create links with other turtles ask link neighbors set color red turtles 1 and 2 turn red ask turtle 1 ask link neighbors set color blue turtle 0 turns blue end lt breed gt neighbor link neighbor lt breed gt neighbor turtle link neighbor turtle Reports true if there is an undirected link between turtle and the caller crt 2 ask turtle 0 create link with turtle 1 show link neighbor turtle 1 prints true 382 NetLogo Dictionary NetLogo 4 1 2 User Manual ask turtle 1 show link neighbor turtle 0 7 prints true netlogo applet netlogo applet Reports true if the model is running as an applet netlogo version netlogo version Reports a string containing the version number of the NetLogo you are running show netlogo version gt 4 1 2 new seed new seed Reports a number suitable for seeding the random number generator The numbers reported by new seed are based on the current date and time in milliseconds and lie in NetLogo s allowed range of integers 9007199254740992 to 9007199254740992 new seed never reports the same number twice in succession This is accomplished by waiting a millise
469. se Example print gogo ping gogo sensor gogo sensor sensor Reports the numeric value of the sensor named sensor Sensors are identified by numbers 1 to 8 Values range between 0 1023 1023 is returned when there is no sensor attached to the port highest resistance or when the sensor is an open state Zero is returned when the sensor is short circuited no resistance Examples print gogo sensor 1 7 prints the value of sensor 1 foreach 12345678 print word Sensor gogo sensor 7 prints the value of all sensors if gogo sensor 1 lt 500 ask turtles fd 10 7 will move all turtles 10 steps forward if sensor 1 s value is less than 500 loop if gogo sensor 1 lt 500 ask turtles fd 10 1 7 will continuously check sensor 1 s value and 77 move all turtles 10 steps forward every time 7 that the sensor value is less than 500 gogo set burst mode gogo set burst mode sensor list high speed mode Turns on burst mode for the sensors in sensor list If high speed mode is true then high speed burst mode will be used If it is false then low speed burst mode will be used See also gogo burst value and gogo stop burst mode Examples gogo set burst mode 1 2 3 true 5 turns on high speed burst mode for sensors 1 2 and 3 gogo set burst mode 4 false 272 NetLogoLab and the GoGo Board Extension NetLogo 4 1 2 User Manual 5 turns on low speed burst mode for sensor 4 5 this
470. se four buttons will rotate or flip the entire shape unless an element is selected in which case only that element is affected These buttons are especially handy in conjunction with the Duplicate button if you want to make shapes that are symmetrical For example if you were making a butterfly you could draw the butterfly s left wing with the polygon tool then duplicate the wing with the Duplicate button then turn the copy into a right wing with the Flip Horizontal button Shape design It s tempting to draw complicated interesting shapes but remember that in most models the patch size is so small that you won t be able to see very much detail Simple bold iconic shapes are usually best 158 Shapes Editor Guide NetLogo 4 1 2 User Manual Keeping a shape When the shape is done give it a name and press the Done button at the bottom of the editing window The shape and its name will now be included in the list of shapes along with the default shape Creating and editing link shapes Managing link shapes is very similar to managing turtle shapes So you can create a new shape but pressing the New button or you can edit existing shapes when you are done editing a shape press Done if you want to keep it Changing link shape properties There are several different properties for each link shape that you are allowed to change e Name link shapes can have the same name as turtle shapes but must be unique among link shapes
471. se most of the methods on the App class may only be called some certain threads Most of the methods may only be called from the AWT event queue thread but a few methods such as main and commmand may only be called from threads other than the AWT event queue thread such as in this example the main thread Rather than continuing to discuss this example in full detail we refer you to the NetLogo API Specification which documents all of the ins and outs of the classes and methods used above Additional methods are available as well Example headless The example code in this case is very similar to the previous example but with methods on an instance of the HeadlessWorkspace Class substituted for static methods on App import org nlogo headless HeadlessWorkspace public class Example2 public static void main String argv HeadlessWorkspace workspace HeadlessWorkspace newInstance try workspace open models Sample Models Earth Science Fire nlogo workspace command set density 62 workspace command random seed 0 workspace command setup workspace command repeat 50 go System out println workspace report burned trees workspace dispose catch Exception ex ex printStackTrace Controlling Guide 201 NetLogo 4 1 2 User Manual The equivalent code in Scala import org nlogo headless HeadlessWorkspace object Example2 def main args Array String
472. section under Sample Models in NetLogo s Models Library Examples of NetLogoLab models Controlling a car The first step when creating a NetLogoLab model is to add the extensions command to NetLogo s procedure tab Just go to the procedures tab and add this line NetLogoLab and the GoGo Board Extension 265 NetLogo 4 1 2 User Manual extensions gogo The second step is to create a button to connect NetLogo to the GoGo board using the correct serial port for your operating system as described above gogo open COM1 for Windows machines When you are done creating the button the edit dialog should look like this Button Agent s Observer Forever Commands gogo open COML Display name setup Action key Now let s actually start the model Imagine that we want to control a car with four wheels and two motors attached to the back wheels We will assume that you have built such as car and connected the motors to the output ports a and b on the GoGo board One very simple approach could be to create two buttons for each motor on and off Interface Information Procedures F r B pam Edit Delete Add Motor Motor B e off off The code associated with these buttons is very simple for the on button we could simply have gogo talk to output ports a gogo output port on 266 NetLogoLab and the GoGo Board Extension NetL
473. sers Group and or search past messages on the group Are NetLogo models runs scientifically reproducible Yes NetLogo s agent scheduling algorithms are deterministic and NetLogo always uses Java s strict math library which gives bit for bit identical results regardless of platform But keep the following cautions in mind FAQ Frequently Asked Questions 303 NetLogo 4 1 2 User Manual e If your model uses random numbers then in order to get reproducible behavior you must use the random seed command to set the random seed in advance so that your model will receive the exact same sequence of random numbers every time Remember that agentsets are always in random order so anything you do with agentsets uses random numbers e If your model uses the every or wait Commands in such a way that affects the outcome of the model then you may get different results on different computers or even on the same computer since the model may run at a different speed e In order to reproduce model runs exactly you must be using the exact same version of NetLogo The details of the agent scheduling mechanism and the random number generator may change between NetLogo versions and other changes bugfixes in the engine language changes and so forth may also affect the behavior of your model Then again they may not e We have expended every effort to make NetLogo model runs fully reproducible but of course this can never truly be an iron clad gua
474. ses 50 of its variable 77 chemical to its neighboring 4 patches Thus each patch gets 1 4 of 50 of the chemical from each neighboring patch directed link breed directed link breed lt ink breeds gt lt link breed gt This keyword like the globals and breeds keywords can only be used at the beginning of the Procedures tab before any procedure definitions It defines a directed link breed Links of a particular breed are always all directed or all undirected The first input defines the name of the agentset associated with the link breed The second input defines the name of a single member of the breed Directed links can be created using create link s to and create link s from but not create link s with Any link of the given link breed e is part of the agentset named by the link breed name e has its built in variable breed set to that agentset 336 NetLogo Dictionary NetLogo 4 1 2 User Manual e is directed or undirected as declared by the keyword Most often the agentset is used in conjunction with ask to give commands to only the links of a particular breed directed link breed streets street directed link breed highways highway to setup clear all ert 2 7 create a link from turtle 0 to turtle 1 ask turtle 0 create street to turtle 1 Create a link from turtle 1 to turtle 0 ask turtle 0 create highway from turtle 1 end ask turtle 0 show one of in links 7 prints street 0 1
475. ses it If it doesn t watch something else such as a plot To get a feel for what s going on it may help to gradually move the slider to the right rather than moving it all the way to the right all at once If you find the updates too infrequent at the rightmost position just don t push the slider that far Can I use the mouse to paint in the view NetLogo does not have a built in set of painting tools for painting in the view But with only a few lines of code you can add painting capability to your model To see how it s done look at Mouse Example in the Code Examples section of the Models Library The same techniques can be used to let the user interact with your model using the mouse in other ways too 308 FAQ Frequently Asked Questions NetLogo 4 1 2 User Manual Another possibility is to create an image in another program and import it using the import items on the File menu or the import primitives How big can my model be How many turtles patches procedures buttons and so on can my model contain We have tested NetLogo with models that use hundreds of megabytes of RAM and they work fine We haven t tested models that use gigabytes of RAM though Theoretically it should work but you might hit some limits that are inherent in the underlying Java VM and or operating system either designed in limits or bugs The NetLogo engine has no fixed limits on size By default though NetLogo ships with a one gigabyte ce
476. sible for the tick counter to take on in between floating point values To advance the tick counter by a fractional amount use the tick advance command This command takes a numeric input specifying how far to advance the tick counter A typical use of fractional ticks is to approximate continuous or curved motion See for example the GasLab models in the Models Library under Chemistry amp Physics These models calculate the exact time at which a future event is to occur then advance the tick counter to exactly that time View Updates The view in NetLogo lets you see the agents in your model on your computer s screen As your agents move and change you see them moving and changing in the view Of course you can t really see your agents directly The view is a picture that NetLogo paints showing you how your agents look at a particular instant Once that instant passes and your agents move and change some more that picture needs to be repainted to reflect the new state of the world Repainting the picture is called updating the view When does the view get updated This section discusses how NetLogo decides when to update the view and how you can influence when it gets updated NetLogo offers two updates modes continuous updates and tick based updates You can switch between NetLogo s two view update modes using a popup menu at the top of the Interface tab Continuous updates are the default when you start up NetLogo or st
477. sk the patches to set color red an error message occurs Command Center MA Clear turtles gt set color yellow ERROR You can t use COLOR in a patch context because COLOR is turtle only patches gt set color red e Type set pcolor red instead and press return 44 Tutorial 2 Commands NetLogo 4 1 2 User Manual We call color and pcolor variables Some commands and variables are specific to turtles and some are specific to patches For example the color variable is a turtle variable while the pcolor variable is a patch variable Go ahead and practice altering the colors of the turtles and patches using the set command and these two variables To be able to make more changes to the colors of turtles and patches or shall we say cars and backgrounds we need to gain a little insight into how NetLogo deals with colors In NetLogo all colors have a numeric value In all of the exercises we have been using the name of the color This is because NetLogo recognizes 16 different color names This does not mean that NetLogo only recognizes 16 colors There are many shades in between these colors that can be used too Here s a chart that shows the whole NetLogo color space black 0 white 9 9 gray 5 8 o 9 9 red 15 13 om 19 199 orange 25 21 22 23 28 29 299 brown 35 a o p a 38 39 399 yellow 45 AQ M22 dg 48 49 499 green 55 SM E 58 59 599 lime 65 61 62 63 68 69 69 9 turquoise 75 P 2 F222 73
478. sn t include everything you might expect to be present Some facilities exist but are not yet documented If you don t see a capability you want please let us know Do not hesitate to contact us at feedback ccl northwestern edu with questions as we may be able to find a workaround or provide additional guidance where our documentation is thin Extensions Guide 237 NetLogo 4 1 2 User Manual Hearing from users of this API will also allow us to appropriately focus our efforts for future releases We are committed to making NetLogo flexible and extensible and we very much welcome your feedback 238 Extensions Guide Array and Table Extensions These extensions add two new data structures to NetLogo arrays and hash tables When to use In general anything you can do with an array or table you could also just use a list for But you may want to consider using an array or table instead for speed reasons All three data structures list array and table have different performance characteristics so you may be able to make your model run faster by selecting the appropriate data structure Arrays are useful when you need a collection of values whose size is fixed You can quickly access or alter any item in an array if you know its position Tables are useful when you need to do associate values with other values For example you might make a table of words and their definitions Then you can look up the definition of any word Here t
479. so preserving the round shape of the that the earth covers the entire Earth in this Orthographic NetLogo View which in this case GIS Extension 281 NetLogo 4 1 2 User Manual projection distorts the shape of the Earth gis set world envelope gis set world envelope gis envelope A shorthand for setting the transformation by mapping the envelope of the NetLogo world to the given envelope in GIS space while keeping the scales along the x and y axis the same It is equivalent to set transformation gis envelope list min pxcor max pxcor min pycor max pycor This primitive is supplied because most of the time you ll want to set the envelope of the entire NetLogo world rather than just a part of it gis set world envelope ds gis set world envelope ds gis envelope A shorthand for setting the transformation by mapping the envelope of the NetLogo world to the given envelope in GIS space using different scales along the x and y axis if necessary Itis equivalent to set transformation ds gis envelope list min pxcor max pxcor min pycor max pycor See the pictures above for the difference between using equal scales for x and y coordinates and using different scales gis world envelope gis world envelope Reports the envelope bounding rectangle of the NetLogo world transformed into GIS space An envelope consists of a four element list of the form minimum x maximum x minimum y maximum y gis envelope of gis envelope
480. so depends on some constant factors that are beyond the scope of this model the rate of reproduction etc System Dynamics Guide 177 NetLogo 4 1 2 User Manual e Create a Variable and name it sheep birth rate Set its value to 0 04 e Draw a Link from the sheep birth rate Variable to the sheep births Your diagram should look something like this sheep birth rate sheep births The sheep births Flow has a red label because we haven t given it an expression Red indicates that there s something missing from that part of the diagram The amount of sheep flowing into our stock will depend positively with the number of sheep and the sheep birth rate e Edit the sheep births Flow and set the expression to sheep birth rate sheep We now have a complete diagram To see the NetLogo code generated by our diagram you can click on the Procedures tab of the System Dynamics Modeler window It looks like this 178 System Dynamics Guide NetLogo 4 1 2 User Manual gt System dynamics model globals globals constants sheep birth rate stock values sheep size of each step see SYSTEM DYNAMICS GO dt Initializes the system dynamics model Call this in your model s SETUP procedure to system dynamics setup reset ticks set dt 0 1 5 initialize constant values set sheep birth rate 04 5 initialize stock values set sheep 100 end Step through the system dynamics model by performing next iter
481. solved relative to the location of the current model or the user s home directory if the current model hasn t been saved yet Currently two types of data file are supported e shp ESRI shapefile contains vector data consisting of points lines or polygons When the target file is a shapefile 1vad dataset reports a VectorDataset e asc or grd ESRI ascii grid contains raster data consisting of a grid of values When the target file is an ascii grid file load dataset reports a RasterDataset gis store dataset gis store dataset dataset file Saves the given dataset to the given file If the name of the file does not have the proper file extension the extension will be automatically appended to the name Relative paths are resolved relative to the location of the current model or the user s home directory if the current model hasn t been saved yet Currently this primitive only works for RasterDatasets and it can only save those datasets as ESRI ascii grid files gis type of gis type of dataset Reports the type of the given GIS dataset either VECTOR or RASTER gis patch dataset gis patch dataset patch variable Reports a new raster whose cells correspond directly to NetLogo patches and whose cell values consist of the values of the given patch variable This primitive is basically the inverse of 284 GIS Extension NetLogo 4 1 2 User Manual apply raster apply raster copies values from a raster dataset to a p
482. some interesting behavior in your model now Some turtles die off some new turtles are created hatched and some grass grows back This is exactly what we set out to do If you continue to watch your monitors in your model you will see that the count turtles and green patches monitors both fluctuate Is this pattern of fluctuation predictable Is there a relationship between the variables It d be nice if we had a easier way to track the changes in the model behavior over time NetLogo allows us to plot data as we go along That will be our next step Plotting To make plotting work we ll need to create a plot in the Interface tab and set some settings in it Then we ll add one more procedure to the Procedures tab which will update the plot for us Let s do the Procedures tab part first 64 Tutorial 3 Procedures NetLogo 4 1 2 User Manual e Change setup to call the new procedure do plots which we re about to add to setup clear all setup patches setup turtles do plots end e Also change go to call the do plots procedure LO go move turtles gat grass check death reproduce regrow grass do plots end e Now add the new procedure What we re plotting will be be the number of turtles and the number of green patches versus time At each time step a single run through the go procedure these values are added to the plot tordo plots set current plot Totals set current plot pen turtles plot count turtles set
483. sorted bugfixes to view mirroring and plot mirroring removed obsolete hubnet send view command new activity Memory HubNet improved activity Sampler overhauled now verified improved Code Example Template new Code Examples Client Perspective Example Client Overrides Example s NIELS suite of electromagnetism models expanded and revamped and is now found in Curricular Models new biology model Sunflower Emergent new social science models Sugarscape 1 2 and 3 new computer science models Simulated Annealing PageRank new game Projectile Attack eff 40 o o e mode new code examples Move Towards Target Example Transparency Example new evolution model Bug Hunt Drift in Curricular Models new ProbLab probability models in Curricular Models Histo Blocks 4 Blocks 4 Block Stalagmites 4 Block Two Stalagmites Sampler Solo improved evolution models Bug Hunt Camouflage includes RGB genes measure of genetic variance Bird Breeder conceptual fix Bug Hunt Speeds overhaul improved Biology models Daisyworld bugfix Flocking bugfix Wolf Sheep Predation bugfix improved Earth Science model Percolation colors clarified info improved Computer Science models Artificial Neural Net code overhaul Dining Philosophers simplified improved chemistry models Simple Kinetics 1 amp 2 bugfix Connected Chemistry 3 Circular Particles bugfix improved code examples Moore and
484. ssages are disabled by default since debug is lower level than info The rest of the body of the configuration file overrides properties of the root logger in a few specific loggers or categories as they are known in the configuration file the terms can be assumed to be synonymous for the proposes of this document That is it turns off the WIDGET TURTLES and LINKS loggers by default To re enable them you can changes the priority from off to info like this lt category name org nlogo log Logger TURTLES gt lt priority value info gt lt category gt or you can simply remove the entire reference to the category from the configuration file as it is not serving any other purpose Advanced Configuration This is only a basic introduction to configuration files for logging in NetLogo There are many more configuration options available through the log4j framework See the log4j documentation 198 Logging Controlling Guide NetLogo can be invoked and controlled by another program running on the Java Virtual Machine For example you might want to call NetLogo from a small program that does something simple like automate a series of model runs Or you might want to embed NetLogo models in a larger application This section of the User Manual introduces this facility for Java programmers We ll assume that you know the Java language and related tools and practices But note that our API s are also usable from other languages f
485. st See also n of NetLogo Dictionary 385 NetLogo 4 1 2 User Manual or boolean1 or boolean2 Reports true if either boolean1 or boolean2 or both is true Note that if condition1 is true then condition2 will not be run since it can t affect the result if pxcor gt 0 or pycor gt 0 set pcolor red patches turn red except in lower left quadrant other other agentset Reports an agentset which is the same as the input agentset but omits this agent show count turtles here gt 10 show count other turtles here gt 9 other end other end If run by a turtle reports the turtle at the other end of the asking link If run by a link reports the turtle at the end of the link that isn t the asking turtle These definitions are difficult to understand in the abstract but the following examples should help ask turtle O create link with turtle 1 ask turtle 0 ask link 0 1 show other end prints turtle 1 ask turtle 1 ask link O 1 show other end prints turtle 0 ask link 0 1 ask turtle 0 show other end prints turtle 1 As these examples hopefully make plain the other end is the end that is neither asking nor being asked out lt breed gt neighbor out link neighbor out lt breed gt neighbor turtle out link neighbor turtle Reports true if there is a directed link going from the caller to turtle 386 NetLogo Dictionary NetLogo 4 1 2 User Manual CEU 2 as
486. st be called before this reporter can be used and there must be data remaining in the file Use the reporter file at end to determine if you are at the end of the file file open my file txt print file read characters 5 Current line in file is Hello World gt Hello See also file open 346 NetLogo Dictionary NetLogo 4 1 2 User Manual file read line file read line Reads the next line in the file and reports it as a string It determines the end of the file by a carriage return an end of file character or both in a row It does not return the line terminator characters Also note that the file open command must be called before this reporter can be used and there must be data remaining in the file Use the reporter file at end to determine if you are at the end of the file file open my file txt print file read line gt Hello World See also file open file show file show value Prints value to an opened file preceded by this agent agent and followed by a carriage return This agent is included to help you keep track of what agents are producing which lines of output Also all strings have their quotes included similar to file write Note that this command is the file i o equivalent of show and file open needs to be called before this command can be used See also file print file type and file write file type file type value Prints value to an opened file not followed by a carriage r
487. stalled you can load the package by entering the following into your Mathematica notebook lt lt NetLogo Launching NetLogo from Mathematica To begin your NetLogo session in Mathematica type the following into your notebook Nistar uyou r ne rogor pala where your netlogo path is the directory that netlogo is located in Typically on a Macintosh computer this will be Applications NetLogo 4 1 Loading a model To load a model you must specify the full path of the model In this example we will load the Forest Fire model and the path will be given using the typical Macintosh install location NLLoadModel Applications NetLogo 4 1 models Sample Models Earth Science Fire nlogo Executing a NetLogo command Commands can be executed by passing a string of commands to NLCommand The NLCommand function automatically splices common Mathematica data types into strings suitable for NetLogo The following commands set the density using a single string or set the density using a Mathematica defined variable myDensit y NLCommand set density 50 myDensity 60 NLCommand set density myDensity Reporting information from NetLogo NetLogo data can be reported back to Mathematica using NLReport This includes numbers strings boolean values and lists NLReport count turtles 206 Mathematica Link NetLogo 4 1 2 User Manual NiReportluQqiistp coripycom ot not MO patches For more in
488. stead Here s an example sort by size of 1 lt size of 2 turtles This returns a list of turtles sorted in ascending order by their turtle variable size Asking a list of agents Once you have a list of agents you might want to ask them each to do something To do this use the foreach and ask commands in combination like this foreach sort turtles ask This will ask each turtle in ascending order by who number Substitute patches for turtles to ask patches in left to right top to bottom order If you use foreach like this the agents in the list run the commands inside the ask sequentially not concurrently Each agent finishes the commands before the next agent begins them Note that you can t use ask directly on a list of turtles ask only works with agentsets and single agents Performance of lists Programming Guide 111 NetLogo 4 1 2 User Manual If your model makes especially heavy use of lists especially long lists you may need to know the speed of the various NetLogo list operations to help you write code that runs fast NetLogo lists are singly linked lists This is a technical term from computer science that means that when NetLogo needs to find an item in a list it must start at the beginning of the list and go from item to item until it finds the one it wants For example to find the 100th item NetLogo must step through the previous 99 items one at a time It also means that ce
489. stributed under the following license Copyright c 2000 2005 INRIA France Telecom All rights reserved Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met 1 Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer 8 Copyright and License Information NetLogo 4 1 2 User Manual 2 Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided with the distribution 3 Neither the name of the copyright holders nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDI
490. t ride me ride me x Asks the observer to ride this turtle See also ride right rt right number The turtle turns right by number degrees If number is negative it turns left round round number Reports the integer nearest to number If the decimal portion of number is exactly 5 the number is rounded in the positive direction Note that rounding in the positive direction is not always how rounding is done in other software programs In particular it does not match the behavior of StarLogoT which always rounded numbers ending in 0 5 to the nearest even integer The rationale for this behavior is that it matches how turtle coordinates relate to patch coordinates in NetLogo For example if a turtle s xcor is 4 5 then it is on the boundary between a patch whose pxcor is 4 and a patch whose pxcor is 5 but the turtle must be considered to be in one patch or the other so the turtle is considered to be in the patch whose pxcor is 4 because we round towards the positive numbers show round 4 2 gt Y show round 4 5 gt 5 show round 4 5 gt 4 See also precision ceiling floor NetLogo Dictionary 403 NetLogo 4 1 2 User Manual run run string This agent interprets the given string as a sequence of one or more NetLogo commands and runs them The code runs in the agent s current context which means it has access to the values of local variables myself and so on The code must be compi
491. t color of turtle 0 red Can be rewritten as ask turtle 0 set color red It is not necessary to use let or myself since red is red from the point of view of both agents However this Transition Guide 141 NetLogo 4 1 2 User Manual set color of turtle 0 color Must be rewritten as let new color color ask turtle O set color new color or ask turtle 0 set color color of myself in order not to change the meaning since the two agents may have different starting values for color The form using myse1 is briefer but the former using let may be considered clearer depending on context and individual preference Applets Applets created using previous versions of NetLogo will not work unaltered with the 4 1 NetLogoLite jar Resave the applet in 4 1 to make it work Alternately you may edit the HTML find this part code org nlogo window Applet and change it to code org nlogo lite Applet Since NetLogo 3 1 Who numbering Prior to NetLogo 4 0 a dead turtle s who number stored in the who turtle variable could be reassigned to a later newborn turtle In NetLogo 4 0 who numbers are never reused until who numbering is reset to O by the clear all or clear turtles command This change in behavior may break a few old models Turtle creation randomized vs ordered NetLogo 4 0 provides two different observer commands for creating turtles create turtles crt and create ordered turtles cro
492. t finishes If procedure name is not defined then reports 0 profiler start profiler start Instructs the profiler to begin recording user defined procedure calls profiler stop profiler stop Instructs the profiler to stop recording user defined procedure calls profiler reset profiler reset Instructs the profiler to erase all collected data profiler report profiler report Reports a string containing a breakdown of all user defined procedure calls The Calls column contains the number of times a user defined procedure was called The Incl T ms column is the total time in milliseconds it took for the call to complete including the time spent in other user defined procedures The Excl T ms column is the total time in milliseconds spent within that user defined procedure not counting other user define procedures it called The Excl calls column is an estimate of the time in milliseconds spent in that user defined procedure for each call Here is example output 276 Profiler Extension Sorted by Exclusive Time Name CALLTHE CALLME REPORT Sorted by Inclusive Time Name CALLTHE CALLME REPORT Sorted by Number of Calls Name CALLTHEM Profiler Extension NetLogo 4 1 2 User Manual Calls 13 13 13 Calls w w Calls 13 Incl T ms 26 066 6 413 0 177 Excl T ms 19 476 6 413 0 177 Excl calls 1 498
493. t is in a different random order This helps you keep your model from treating any particular turtles patches or links differently from any others unless you want them to be Since the order is random every time no one agent always gets to go first You ve seen the turtles primitive which reports the agentset of all turtles the patches primitive which reports the agentset of all patches and the Links primitive which reports the agentset of all links But what s powerful about the agentset concept is that you can construct agentsets that contain only some turtles some patches or some links For example all the red turtles or the patches with pxcor evenly divisible by five or the turtles in the first quadrant that are on a green patch or the links connected to turtle 0 These agentsets can then be used by ask or by various reporters that take agentsets as inputs One way is to use turtles here Or turtles at to make an agentset containing only the turtles on my patch or only the turtles on some other patch at some x and y offsets There s also turtles on so you can get the set of turtles standing on a given patch or set of patches or the set of turtles standing on the same patch as a given turtle or set of turtles Here are some more examples of how to make agentsets all other turtles other turtles all other turtles on this patch other turtles here all red turtles turtles with color red all red turtles
494. t path allowed by Programming Guide 129 NetLogo 4 1 2 User Manual the topology For example the distance from the center of the patches in the bottom right corner min pxcor min pycor and the upper left corner max pxcor max pycor will be as follows for each topology given that the min and max pxcor and pycor are 2 e Torus sqrt 2 1 414 this will be the same for all world sizes since the patches are directly diagonal to each other in a torus e Box sqrt world width 2 world height 2 7 07 e Vertical Cylinder sqrt world height 2 1 5 099 e Horizontal Cylinder sqrt world width 2 1 5 099 All the other primitives will act similarly to distance If you formerly used no wrap primitives in your model we recommend removing them and changing the topology of the world instead There are a number of reasons to change your model to use topologies rather than no wrap primitives First we expect if you are using no wrap primitives you are actually modeling a world that is not a torus If you use a topology that matches the world you are modeling NetLogo does automatic bounds checking for you it should make your life easier your code simpler to understand and it adds visual cues to help the model user understand what you are modeling Note that even with no wrap primitives it was very difficult to model cylinders since the no wrap primitives report the distance or heading when wrapping is not allowed in either directi
495. t that client in a turtle variable Since we don t want to require users to log out and log back in every time we setup the activity we don t want to kill all the turtles instead we want to set all the variables back to initial values and notify the clients of any changes we make more on that later Receiving messages from clients During the activity you will be transferring data between the HubNet clients and the server Most HubNet activities will call a procedure in the go loop that checks for new messages from clients in this case it s called listen clients to listen clients while hubnet message waiting hubnet fetch messag ifelse hubnet enter message create new student ifelse hubnet exit message remove student execute command hubnet message tag end As long as there are messages in the queue this loop fetches each message one at a time hubnet fetch message makes the next message in the queue the current message and sets the reporters hubnet message source hubnet message tag and hubnet message to the appropriate values The clients send messages when the users login and logout any time the user manipulates one of the interface elements that is pushes a button moves a slider clicks in the view etc We step through each message and decide what action to take depending on the type of message enter exit or other the hubnet message tag the name of the interface element and the hub
496. t you will be able to see relationships form between different sliders and the behavior of the system After all the runs are over a dataset is generated which you BehaviorSpace Guide 161 NetLogo 4 1 2 User Manual can open in a different tool such as a spreadsheet database or scientific visualization application and explore By enabling you to explore the entire space of behaviors a model can exhibit BehaviorSpace can be a powerful assistant to the modeler How lt Works To begin using BehaviorSpace open your model then choose the BehaviorSpace item on NetLogo s Tools menu Managing experiment setups The dialog that opens lets you create edit duplicate delete and run experiment setups Experiments are listed by name and how by model runs the experiment will consist of Experiment setups are considered part of a NetLogo model and are saved as part of the model To create a new experiment setup press the New button Creating an experiment setup In the new dialog that appears you can specify the following information Note that you don t always need to specify everything some parts can be left blank or left with their default values depending on your needs Experiment name If you have multiple experiments giving them different names will help you keep them straight Vary variables as follows This is where you specify which settings you want varied and what values you want them to take Variables can inclu
497. tLogo 4 1 2 User Manual Code Examples Network Example Network Import Example Giant Component Small Worlds Preferential Attachment Ask Concurrent In previous versions of NetLogo ask was concurrent by default As of NetLogo 4 0 ask is serial that is the agents run the commands inside the ask one at a time The following information describes the behavior of the ask concurrent command which behaves the way the old ask behaved ask concurrent produces simulated concurrency via a mechanism of turn taking The first agent takes a turn then the second agent takes a turn and so on until every agent in the asked agentset has had a turn Then we go back to the first agent This continues until all of the agents have finished running all of the commands An agent s turn ends when it performs an action that affects the state of the world such as moving or creating a turtle or changing the value of a global turtle patch or link variable Setting a local variable doesn t count The forward d and back bk commands are treated specially When used inside ask concurrent these commands can take multiple turns to execute During its turn the turtle can only move by one step Thus for example fd 20 is equivalentto repeat 20 fd 1 where the turtle s turn ends after each run of fd If the distance specified isn t an integer the last fraction of step takes a full turn So for example fd 20 3 is equivalent to repeat 20 fd 1
498. tch 4 0 patch 5 0 See also max one of with max max one of max one of agentset reporter Reports the agent in the agentset that has the highest value for the given reporter If there is a tie this command reports one random agent with the highest value If you want all such agents use with max instead show max one of patches count turtles here 7 prints the first patch with the most turtles on it See also max n of with max max pxcor max pycor max pxcor max pycor NetLogo Dictionary 373 NetLogo 4 1 2 User Manual These reporters give the maximum x coordinate and maximum y coordinate respectively for patches which determines the size of the world Unlike in older versions of NetLogo the origin does not have to be at the center of the world However the maximum x and y coordinates must be greater than or equal to zero Note You can set the size of the world only by editing the view these are reporters which cannot be set crt 100 setxy random float max pxcor random float max pycor 7 distributes 100 turtles randomly in the first quadrant See also min pxcor min pycor world width and world height mean mean list Reports the statistical mean of the numeric items in the given list Ignores non numeric items The mean is the average i e the sum of the items divided by the total number of items show mean xcor of turtles 7 prints the average of all the turtles x coordinates medi
499. tching VectorFeature is found gis find less than gis find less than VectorDataset property name value Reports a list of all VectorFeatures in the given dataset whose value for the property property name is less than the given value String values are compared using case sensitive lexicographic order as defined in the Java Documentation Using a string value for a numeric property or a numeric value for a string property will cause an error gis find greater than gis find greater than VectorDataset property name value Reports a list of all VectorFeatures in the given dataset whose value for the property property name is greater than the given value String values are compared using case sensitive lexicographic order as defined in the Java Documentation Using a string value for a numeric property or a numeric value for a string property will cause an error gis find range gis find range VectorDataset property name minimum value maximum value Reports a list of all VectorFeatures in the given dataset whose value for the property property name is strictly greater than minimum value and strictly less than maximum value String values are compared using case sensitive lexicographic order as defined in the Java Documentation Using a string value for a numeric property or a numeric value for a string property will cause an error gis property minimum gis property minimum VectorDataset property name Reports the smallest value for the given pr
500. te of the values currently displayed in the client interface will not be accessible in other parts of the model That s why we ve declared a student s own variable for every interface element that has a state sliders switches etc When we receive the message from the client we set the turtle variable to the content of the message if hubnet message tag step size ask students with user id hubnet message source set step size hubnet message Since buttons don t have any associated data there is generally no associated turtle variable instead they indicate an action taken by the client just as with a regular button there is often procedure associated with each button that you call whenever you receive a message indicating the button has been pressed Though itis certainly not required the procedure is often a turtle procedure that is something that the student turtle associated with the message source can execute if command move left set heading 270 Bel ay HubNet Authoring Guide 191 NetLogo 4 1 2 User Manual Sending messages to clients As mentioned earlier you can also send values to any interface elements that display information monitors sliders switches choosers and input boxes note that plots and the view are special cases that have their own sections There are two primitives that allow you to send information hubnet send and hubnet broadcast Broadcast sends the information to all the
501. tem list position string1 string2 On a list reports the first position of item in list or false if it does not appear On strings reports the position of the first appearance string1 as a substring of string2 or false if it does not appear Note The positions are numbered beginning with 0 not with 1 7 suppose mylist is 2 7 4 7 Bob show position 7 mylist gt 1 show position 10 mylist gt false show position in string gt 3 See also member precision precision number places Reports number rounded to places decimal places If places is negative the rounding takes place to the left of the decimal point show precision 1 23456789 3 gt 1 235 show precision 3834 3 gt 4000 See also round ceiling floor 394 NetLogo Dictionary NetLogo 4 1 2 User Manual print print value Prints value in the Command Center followed by a carriage return This agent is not printed before the value unlike show See also show type and write See also output print pxcor pycor pxcor ER A These are built in patch variables They hold the x and y coordinate of the patch They are always integers You cannot set these variables because patches don t move pxcor is greater than or equal to min pxcor and less than or equal to max pxcor similarly for pycor and min pycor and max pycor All patch variables can be directly accessed by any turtle standing on the patch See also xcor ycor
502. tensions Since NetLogo 3 0 Agentsets If your model is behaving strangely or incorrectly perhaps it s because since NetLogo 3 1 agentsets are now always in random order In prior versions of NetLogo agentsets were always in a fixed order If your code depended on that fixed order then it won t work anymore How to fix your model to work with randomized agentsets depends on the details of what your code is doing In some situations it is helpful to use the sort or sort by primitives to convert an agentset random order into a list of agents fixed order See Lists of agents in the Lists section of the Programming Guide Wrapping If you are seeing pieces of turtle shapes wrapping around the view edges it s because NetLogo 3 0 allowed you to turn off such wrapping in the view without affecting the behavior of the model Since NetLogo 3 1 if you don t want the view to wrap you must make it so the world doesn t wrap using the new topology feature Making this change may require other changes to your model though See the Topology section of the Programming Guide for a thorough discussion of how to convert your model to take advantage of this new feature Random turtle coordinates Many models made in NetLogo 3 0 or earlier use setxy random world width random world height to scatter turtles randomly using either random or random float It only works if world wrapping is on Why Because when wrapping is on you can set coordinat
503. terns forming For example in social settings people tend to exhibit different behavior than when they are at work or home Individuals who are confident within their work environment may become shy and timid at a social gathering And others who are quiet and reserved at work may be the party starter with friends The patterns may also depend on what kind of gathering it is In some settings people are trained to organize themselves into mixed groups for example party games or school like activities But in a non structured atmosphere people tend to group in a more random manner Is there any type of pattern to this kind of grouping Let s take a closer look at this question by using the computer to model human behavior at a party NetLogo s Party model looks specifically at the question of grouping by gender at parties why do groups tend to form that are mostly men or mostly women Let s use NetLogo to explore this question What to do 1 Start NetLogo 2 Choose Models Library from the File menu NetLogo MES Edit Tools Zoon 8 4 New N tl 3 Open O Models Library 3M t mi tet t B Deleg Save 36S Save AS Save As Applet Print dE P 3 Open the Social Science folder 4 Click on the model called Party Sample Model Party 27 NetLogo 4 1 2 User Manual 5 Press the open button 6 Wait for the model to finish loading 7 optional Make the NetLogo window bigger so you can see e
504. the agentset capabilities described above are immediately available with the sheep agentset The following new primitives are also automatically available once you define a breed create sheep hatch sheep sprout sheep sheep here sheep at sheep on and is a sheep Also you can use sheep own to define new turtle variables that only turtles of the given breed have It s allowed for more than one breed to own the same variable A turtle s breed agentset is stored in the breed turtle variable So you can test a turile s breed like this if breed wolves 104 Programming Guide NetLogo 4 1 2 User Manual Note also that turtles can change breeds A wolf doesn t have to remain a wolf its whole life Let s change a random wolf into a sheep ask one of wolves set breed sheep The set default shape primitive is useful for associating certain turtle shapes with certain breeds See the section on shapes below Here is a quick example of using breeds breed mice mouse breed frogs frog mice own cheese to setup clear all create mice 50 set color white set cheese random 10 create frogs 50 set color green end Code Example Breeds and Shapes Example Link Breeds Link breeds are very similar to turtle breeds however there are a few differences When you declare a link breed you must declare whether it is a breed of directed or undirected links by using the directed 1ink breed
505. the allowable range of turtle coordinates along the z axis Turtle coordinates range from min pzcor 0 5 inclusive to max pzcor 0 5 exclusive ask turtles 77 move each turtle to a random point setxyz random xcor random ycor random zcor See also random xcor random ycor right right number The turtle turns right by number degrees relative to its current orientation While right in a 2D world only modifies the turtle s heading right in a 3D world may also modify the turtle s pitch and roll Introducing NetLogo 3D 223 NetLogo 4 1 2 User Manual See also right and left roll roll x This is a built in turtle variable Roll is the angle between the wing tip of the turtle and the xy plane This is a number greater than or equal to 0 and less than 360 You can set this variable to make a turtle roll Since roll is always from the turtle s point of view rolling right and left only only change roll regardless of turtle orientation Example set roll 45 77 turtle rotated right set roll roll 10 same effect as roll right 10 See also heading pitch roll left roll right roll left roll left number The wingtip of the turtle rotates to the left number degrees with respect to the current heading and pitch roll right roll right number The wingtip of the turtle rotates to the right number degrees with respect to the current heading and pitch S setxyz setxyz x y Z ig 3D version of setxy
506. the new turtles different colors headings or whatever The new turtles are created all at once then run one at a time in random order If the sprout lt breeds gt form is used the new turtles are created as members of the given breed sprout 5 sprout wolves 10 sprout 1 set color red sprout sheep 1 set color black See also create turtles hatch sart sqrt number Reports the square root of number stamp stamp This turtle or link leaves an image of its shape in the drawing at its current location Note The shapes made by stamp may not be pixel for pixel identical from computer to computer stamp erase stamp erase This turtle or link removes any pixels below it in the drawing inside the bounds of its shape Note The shapes made by stamp erase may not be pixel for pixel identical from computer to computer NetLogo Dictionary 413 NetLogo 4 1 2 User Manual standard deviation standard deviation list Reports the sample standard deviation of a list of numbers Ignores other types of items Note that this estimates the standard deviation for a sample rather than for a whole population using Bessel s correction show standard deviation 1 2 3 4 5 6 gt 1 8708286933869707 show standard deviation energy of turtles 7 prints the standard deviation of the variable energy from all the turtles startup startup gt User defined procedure which if it exists will be called when a model is fi
507. the pitch from this agent to the coordinates x y z If the wrapped distance around the edges of the screen is shorter than the on screen distance towards pitch will report the pitch of the wrapped path towards pitch nowrap never uses the Introducing NetLogo 3D 225 NetLogo 4 1 2 User Manual wrapped path Note In order to get a turtle to face a given location you need to use both towards pitch xyz and towardsxy Note asking for the pitch from an agent to the location it is standing on will cause a runtime error See also towardsxy turtles at lt breeds gt at turtles at dx dy dz lt breeds gt at dx dy dz MEN 3D versions of turtles at and breeds at Reports an agentset containing the turtles on the patch dx dy dz from the caller including the caller itself if it s a turtle 7 suppose I have 40 turtles at the origin show count turtles at 0 0 0 of turtle 0 gt 40 W world depth world depth Reports the total depth of the NetLogo world The depth of the world is the same as max pzcor min pzcor 1 See also max pzcor min pzcor world width and world height Z zcor zcor This is a built in turtle variable It holds the current z coordinate of the turtle This is a floating point number not an integer You can set this variable to change the turtle s location This variable is always greater than or equal to screen edge z and strictly less than screen edge z 226 Introducing NetLogo 3D
508. the plot to readjust itself when it runs out of room If you forget which pen is which click on the Pens label on the top right corner of the plot You might try running the model several times to see what aspects of the plot are the same and which are different Tick counter To make comparisons between plots from one model run and another it is often useful to do the comparison for the same length of model run Learning how to stop or start an action at a specific time can help make this happen by stopping the model at the same point each model run Keeping track of how many times the go procedure is run is a useful way to cue these actions To keep track of this we will use NetLogo s built in tick counter e Change the go procedure to qo OS gt OOO ices move turtles cal grass check death reproduce regrow grass ipa do plots end Tutorial 3 Procedures 67 NetLogo 4 1 2 User Manual e Now setup and run the model The graph and model won t keep running forever They should stop automatically when the tick counter in the Interface tab s toolbar reaches 500 The tick command advances the tick counter by 1 ticks is a reporter which reports the current value of the tick counter clear a11 takes care of resetting the tick counter to O when a new run starts Note that we put tick before do plots That s so if we write plotting code that uses the value of the tick counter it will see the new value not the
509. tial representation is a line segment connecting the two points represented by the turtles the link is connecting e A patch whose spatial representation is a rectangular polygon e An agentset whose spatial representation is the union of the representations of all of the agents it contains e A list containing of any of the items listed here including another list The spatial representation of such a list is the union of the spatial representations of its contents gis intersecting patch set gis intersecting data Reports a new agent set containing only those members of the given agent set which intersect given GIS data which may be any one of a VectorDataset a VectorFeature an Agent an Agent Set or a list containing any of the above RasterDataset Primitives 292 GIS Extension NetLogo 4 1 2 User Manual gis width of gis width of RasterDataset Reports the number of columns in the dataset Note that this is the number of cells from left to right not the width of the dataset in GIS space gis height of gis height of RasterDataset Reports the number of rows in the dataset Note that this is the number of cells from top to bottom not the height of the dataset in GIS space gis raster value gis raster value RasterDataset x y Reports the value of the given raster dataset in the given cell Cell coordinates are numbered from left to right and from top to bottom beginning with zero So the upper left cell is 0 0 and the
510. tio de cian drid dada 429 NR 430 A RSRSRS A DMD NO 430 IM CO ES RR RSRS UND RR ROS 430 E CO TREE PERES RUE RA ee E De MIN E E A ANO e SORTED O 430 BN ARDE RR RR RP RR a PAR e RE SENDA ER OUR eo 430 PEOP e A 430 a A A qu es Dam ta Da 431 PER ES CARS a ERREI ER ND ta alk E D ni 431 XXIV What is NetLogo NetLogo is a programmable modeling environment for simulating natural and social phenomena It was authored by Uri Wilensky in 1999 and has been in continuous development ever since at the Center for Connected Learning and Computer Based Modeling NetLogo is particularly well suited for modeling complex systems developing over time Modelers can give instructions to hundreds or thousands of agents all operating independently This makes it possible to explore the connection between the micro level behavior of individuals and the macro level patterns that emerge from the interaction of many individuals NetLogo lets students open simulations and play with them exploring their behavior under various conditions It is also an authoring environment which enables students teachers and curriculum developers to create their own models NetLogo is simple enough that students and teachers can easily run simulations or even build their own And it is advanced enough to serve as a powerful tool for researchers in many fields NetLogo has extensive documentation and tutorials lt also comes with a Models Library which is a large collection of p
511. tion e user primitives which query the user for input such as user yes or no will cause an exception The NetLogo API Specification contains further details In order to run 3D headless you must make sure that the org nlogo is3D property is set you can either do this by starting Java with the Dorg nlogo is3d true option or you can set it from within Java by using System setProperty as follows public static void main String args org nlogo awt Utils invokeLater new Runnable public void run System setProperty org nlogo is3d true HeadlessWorkspace workspace HeadlessWorkspace newInstance 202 Controlling Guide NetLogo 4 1 2 User Manual try workspace open models 3D Sample Models DLA 3D nlogo workspace command set wiggle angle 70 workspace command random seed 0 workspace command setup workspace command repeat 50 go J System out printin workspace report count patches with pcolor green workspace dispose catch Exception ex ex printStackTrace Note that org nlogo is3D must be set before creating the workspace Example embedding When your program controls NetLogo using the App class the entire NetLogo application is present including tabs menubar and so forth This arrangement is suitable for controlling or scripting NetLogo but not ideal for embedding a NetLogo model in a larger application We also have a distinct but si
512. tionary Here is how they are typically used e print is useful in most situations e show lets you see which agent is printing what e type lets you print several things on the same line e write lets you print values in a format which can be read back in using file read A NetLogo model may optionally have an output area in its Interface tab separate from the Command Center To send output there instead of the Command Center use the output print output show output type and output write commands The output area can be cleared with the clear output command and saved to a file with export output The contents of the output area will be saved by the export world command The import world command will clear the output area and set its contents to the value in imported world file It should be noted that large amounts of data being sent to the output area can increase the size of your exported worlds If you use output print output show output type output write clear output or export output in a model which does not have a separate output area then the commands apply to the output portion of the Command Center Programming Guide 123 NetLogo 4 1 2 User Manual File I O In NetLogo there is a set of primitives that give you the power to interact with outside files They all begin with the prefix file There are two main modes when dealing with files reading and writing The difference is the direction of the flow of dat
513. tivity HubNet is a technology that lets you use NetLogo to run participatory simulations in the classroom In a participatory simulation a whole class takes part in enacting the behavior of a system as each student controls a part of the system by using an individual device such as a networked computer or Texas Instruments graphing calculator For example in the Gridlock simulation each student controls a traffic light in a simulated city The class as a whole tries to make traffic flow efficiently through the city As the simulation runs data is collected which can afterwards be analyzed on a computer or calculator For more information on participatory simulations and their learning potential please visit the Participatory Simulations Project web site Understanding HubNet NetLogo NetLogo is a programmable modeling environment It comes with a large library of existing simulations both participatory and traditional that you can use and modify Content areas include social science and economics biology and medicine physics and chemistry and mathematics and computer science You and your students can also use it to build your own simulations In traditional NetLogo simulations the simulation runs according to rules that the simulation author specifies HubNet adds a new dimension to NetLogo by letting simulations run not just according to rules but by direct human participation Since HubNet builds upon NetLogo we recommend that
514. tle commands create link from turtle create link from turtle commands create link with turtle create link with turtle commands create links to turtleset create links to turtleset commands create links from turtleset create links from turtleset commands create links with turtleset create links with turtleset commands Used for creating breeded and unbreeded links between turtles create link with creates an undirected link between the caller and agent create link to creates a directed link from the caller to agent create link from creates a directed link from agent to the caller When the plural form of the breed name is used an agentset is expected instead of an agent and links are created between the caller and all agents in the agentset The optional command block is the set of commands each newly formed link runs The links are created all at once then run one at a time in random order A node cannot be linked to itself Also you cannot have more than one undirected link of the same breed between the same two nodes nor can you have more than one directed link of the same breed going in the same direction between two nodes If you try to create a link where one of the same breed already exists nothing happens If you try to create a link from a turtle to itself you get a runtime error to setup ert 5 7 turtle 1 creates links with all other turtles 7 the link between the turtle and itself is ignor
515. tle variable Pitch is the angle between the nose of the turtle and the xy plane Heading and pitch together define the forward vector of the turtle or the direction that the turtle is facing This is a number greater than or equal to 0 and less than 360 0 is parallel to the xy plane 90 is parallel to the z axis While you can set pitch we recommend that you use the primitives to turn the turtle Depending on the position more than one relative angle heading pitch and roll may change at once Example j assume roll and heading are 0 set pitch 45 turtle is now north and up set heading heading 10 same effect as tilt up 10 See also heading roll tilt up tilt down right left 222 Introducing NetLogo 3D NetLogo 4 1 2 User Manual pzcor Es w This is a built in patch variable It holds the z coordinate of the patch It is always an integer You cannot set this variable because patches don t move pzcor is greater than or equal to min pzcor and less than or equal to max pzcor All patch variables can be directly accessed by any turtle standing on the patch See also pxcor pycor zcor R random pzcor random pzcor Reports a random integer ranging from min pzcor to max pxcor inclusive ask turtles 7 move each turtle to the center of a random patch setxyz random pxcor random pycor random pzcor See also random pxcor random pycor random zcor random zcor Reports a random floating point number from
516. tles and patches use the wrapped distance around the edges of the world if wrapping is allowed by the topology and the wrapped distance is shorter ask turtles show max one of turtles distance myself 7 each turtle prints the turtle farthest from itself distancexy distancexy xcor ycor Reports the distance from this agent to the point xcor ycor The distance from a patch is measured from the center of the patch Turtles and patches use the wrapped distance around the edges of the world if wrapping is allowed by the topology and the wrapped distance is shorter if distancexy 0 0 gt 10 set color green 7 all turtles more than 10 units from 7 the center of the world turn green downhill downhill4 downhill patch variable downhill4 patch variable Moves the turtle to the neighboring patch with the lowest value for patch variable If no neighboring patch has a smaller value than the current patch the turtle stays put If there are multiple patches with the same lowest value the turtle picks one randomly Non numeric values are ignored downhill considers the eight neighboring patches downhill4 only considers the four neighbors Equivalent to the following code assumes variable values are numeric move to patch here go to patch center let p min one of neighbors patch variable 7 or neighbors4 if patch variable of p lt patch variable face p move to p 338 NetLogo Dictionary NetLogo 4 1
517. to be up to date after the go button stops If you need to specify both the x and y values of the point you want plotted then use plotxy instead Code Example Plotting Example Other kinds of plots By default NetLogo plot pens plot in line mode so that the points you plot are connected by a line If you want to move the pen without plotting you can use the plot pen up command After this command is issued the plot and plotxy commands move the pen but do not actually draw anything Once the pen is where you want it use plot pen down to put the pen back down If you want to plot individual points instead of lines or you want to draw bars instead of lines or points you need to change the plot pen s mode Three modes are available line bar and point Line is the default mode Normally you change a pen s mode by editing the plot This changes the pen s default mode It s also possible to change the pen s mode temporarily using the set plot pen mode command That command takes a number as input O for line 1 for bar 2 for point Histograms A histogram is a special kind of plot that measures how frequently certain values or values in certain ranges occur in a collection of numbers that arise in your model For example suppose the turiles in your model have an age variable You could create a histogram of the distribution of ages among your turtles with the histogram command like this 120 Programming Guide NetLogo 4
518. to the beginning of a list set mylist lput 42 mylist mylist is now 2 7 10 Bob 3 0 2 42 But what if you changed your mind The but 1ast b1 for short reporter reports all the list items but the last set mylist but last mylist mylist is now 2 7 10 Bob 3 0 2 Suppose you want to get rid of item 0 the 2 at the beginning of the list set mylist but first mylist mylist is now 7 10 Bob 3 0 2 Suppose you wanted to change the third item that s nested inside item 3 from 2 to 9 The key is to realize that the name that can be used to call the nested list 3 O 2 is item 3 mylist Then the replace item reporter can be nested to change the list within a list The parentheses are added for clarity set mylist replace item 3 mylist replace item 2 item 3 mylist 9 mylist is now 7 10 Bob 3 0 9 Iterating over lists If you want to do some operation on each item in a list in turn the foreach command and the map reporter may be helpful foreach is used to run a command or commands on each item in a list It takes an input list and a block of commands like this foreach 2 4 6 Every 2 show word created turtles gt created 2 turtles gt created 4 turtles gt created 6 turtles In the block the variable 2 holds the current value from the input list Programming Guide 109 NetLogo 4 1 2 User Manual Here are some more examples of foreach foreach 1 2 3 ask turtles fd
519. top working if the computer goes to sleep If this happens quit the NetLogo application and start over Change the settings on your computer so it won t sleep again My problem is not addressed on this page Please send us an email at feedback ccl northwestern edu Known Limitations If HubNet malfunctions please send us an email at bugs ccl northwestern edu Please note that e HubNet has not yet been extensively tested with large numbers of clients i e more than about 25 Unexpected results may occur with more clients e Out of memory conditions are not handled gracefully e Sending large amounts of plotting messages to the clients can take a long time e NetLogo does not handle malicious clients in a robust manner in other words it is likely vulnerable to denial of service type attacks e Performance does not degrade gracefully over slow or unreliable network connections e If you are on a wireless network or sub LAN the IP address in the HubNet Control Center is not always the entire IP address of the server e Computer HubNet has only been tested on LANs and not on dial up connections or WANs Calculator HubNet Calculator HubNet for Tl Navigator The Tl Navigator Classroom Learning System is a wireless classroom network for TI graphing calculators Tl Navigator users can install a free NetLogo extension which integrates with Tl Navigator and allows the calculators to act as clients for participatory simulations like the one
520. try to run the startup procedure when you open any model That makes it a good place to put code that you want to run once and only once no matter how many times the user runs the model For HubNet we put the commands that initialize the network in startup because once the network is setup we don t need to do so again First specify the type of clients using hubnet set client interface in this case we will be using computer clients hubnet set client interface COMPUTER Then initialize the system using hubnet reset which will ask the user for a session name and open up the HubNet Control Center NetLogo is now ready to start listening for client messages HubNet Authoring Guide 189 NetLogo 4 1 2 User Manual Now that the network is all setup you don t need to worry about calling hubnet set client interface Or hubnet reset again Take a look at the setup procedure in the template model to setup cp cd clear output ask turtles set step size 1 hubnet send user id step size step siz end For the most part it looks like most other setup procedures however you should notice that it does not call clear a11 In this model and in the great majority of HubNet activities in the Models Library we have a breed of turtles that represent the currently logged in clients In this case we ve called this breed students Whenever a client logs in we create a student and record any information we might need later abou
521. ts The first element is a list containing the regression constant followed by the coefficients on each of the independent variables The second element is a 3 element list containing the R statistic the total sum of squares and the residual sum of squares The following code example shows how the matrix regress primitive can be used to perform the same function as the code examples shown in the matrix forecast growth primitives above However keep in mind that the matrix regress primitive is more powerful than this and can have many more independent variables in the regression as indicated in the fourth example below this is equivalent to what the matrix forecast linear growth does let data list 20 25 28 32 35 39 let indep var n values length data list 0 1 2 5 let lin output matrix regress matrix from column list list data list indep var let lincnst item O item 0 lin output let linslpe item 1 item 0 lin output let linR2 item 0 item 1 lin output Note the 6 here is because we want to forecast the value at time t 6 print list lincnst linslpe 6 lincnst linslpe linR2 this is equivalent to what the matrix forecast compound growth does let com log data list map ln 2 20 25 28 32 35 39 let com indep var2 n values length com log data list 0 1 2 5 let com output matrix regress matrix from column list list com log data list com indep var2 let comcnst exp item 0 item 0 c
522. ts an agentset of all the directed links coming in from other nodes to the caller crt 5 ask turtle 0 create links to other turtles show my in links shows an empty agentset ask turtle 1 show my in links shows an agentset containing the link 0 1 my out lt breeds gt my out links my out lt breeds gt my out links Reports an agentset of all the directed links going out from the caller to other nodes ert 5 ask turtle 0 create links to other turtles show my out links shows agentset containing all the links ask turtle 1 show my out links shows an empty agentset myself myself self and myself are very different self is simple it means me patch who asked me to do what I m doing right now myself means the turtle or When an agent has been asked to run some code using myself in that code reports the agent turtle or patch that did the asking myself is most often used in conjunction with of to read or set variables in the asking agent myself can be used within blocks of code not just in the ask command but also hatch sprout of with all with min with max min one of max one of min n of max n of ask turtles 380 NetLogo Dictionary NetLogo 4 1 2 User Manual ask patches in radius 3 set pcolor color of myself each turtle makes a colored splotch around itself See the Myself Example code example for more examples See also self N
523. ts its turn In the following examples setup is a once button and go is a forever button Example 1 The user presses setup then presses go immediately before the setup has popped back up Result setup finishes before go starts Example 2 While the go button is down the user presses setup Result the go button finishes its current iteration Then the setup button runs Then go starts running again Example 3 The user has two forever buttons down at the same time Result first one button runs its code all the way through then the other runs its code all the way through and so on alternating Note that if one button gets stuck in an infinite loop then no other buttons will run Turtle patch and link forever buttons There is a subtle difference between putting commands in a turtle patch or link forever button and putting the same commands in an observer button that does ask turtles ask patches or ask links An ask doesn t complete until all of the agents have finished running all of the commands in the ask So the agents as they all run the commands concurrently can be out of sync with each other but they all sync up again at the end of the ask The same isn t true of turtle patch and link forever buttons Since ask was not used each turtle or patch runs the given code over and over again so they can become and remain out of sync with each other At present this capability is very rarely used
524. turtle and link variable It holds a string that is the name of the turtle or link s current shape You can set this variable to change the shape New turtles and links have the shape default unless the a different shape has been specified using set default shape Example ask turtles set shape wolf 7 assumes you have made a wolf 7 Shape in NetLogo s Turtle Shapes Editor ask links set shape link 1 77 assumes you have made a link 1 shape in 5 the Link Shapes Editor See also set default shape shapes shapes shapes Reports a list of strings containing all of the turtle shapes in the model New shapes can be created or imported from the shapes library or from other models in the Shapes Editor show shapes gt default airplane arrow box bug ask turtles set shape one of shapes show show value Prints value in the Command Center preceded by this agent and followed by a carriage return This agent is included to help you keep track of what agents are producing which lines of output Also all strings have their quotes included similar to write See also print type and write See also output show show turtle st show turtle The turtle becomes visible again 410 NetLogo Dictionary NetLogo 4 1 2 User Manual Note This command is equivalent to setting the turtle variable hidden to false See also hide turtle show link show link The link becomes
525. two numbers were still considered equal New observer gt print 3 3 observer gt print 3 0 3 observer gt print 1 2 3 observer gt print 1 5 1 5 3 observer gt print 3 ll w o 148 Transition Guide NetLogo 4 1 2 User Manual true We expect that only rare models will be negatively impacted by this change A benefit of this change is that NetLogo now supports a much larger range of integers The old range was 2 147 483 648 to 2 147 483 647 around 2 billion the new range is 9 007 199 254 740 992 around 9 quadrillion Agentset building NetLogo 3 1 and some earlier versions included primitives called turtles from and patches from that were occasionally useful for building agentsets In NetLogo 4 0 these primitives have been replaced with new primitives called turtle set and patch set that are much more flexible and powerful Link set exists as well See the entries for these primitives in the NetLogo Dictionary Models that use the old turtles from and patches from will need to be altered by hand to use the new primitives RGB Colors In NetLogo 3 1 RGB and HSB colors could be approximated as NetLogo colors using the rgb and hsb primitives These have been renamed to approximate rgb and approximate hsb and now expect inputs in the range 0 255 not 0 1 The full RGB spectrum is now available in NetLogo so it may no longer be necessary to use these primitives at all You can set any color variable
526. u can only have one interface element with a specific name Having more than one interface element with the same tag in the client interface will result in unpredictable behavior since itis not clear which element you intended to send the information to View Updates on the Clients View mirroring lets views of the world be displayed in clients as well on the server View mirroring is enabled using a checkbox in the HubNet Control Center When mirroring is enabled client views update whenever the view on the server does To avoid excessive network traffic the view should not update more often than necessary Therefore we strongly recommend using tick based updates rather than continuous updates See the View Updates section of the Programming Guide for an explanation of the two types of updates With tick based updates updates happen when a tick or display command runs We recommend using these commands only inside an every block to limit the frequency of view updates and thus also limit network traffic For example every 0 1 display HubNet Authoring Guide 193 NetLogo 4 1 2 User Manual If there is no View in the clients or if the Mirror 2D View on Clients checkbox in the HubNet Control Center is not checked then no view updates are sent to the clients Clicking in the View on Clients If the View is included in the client two messages are sent to the server every time the user clicks in the view The first message whe
527. udes the GoGo and QuickTime for Java extensions Writing Extensions This section of the User Manual introduces this facility for Java programmers We ll assume that you know the Java language and related tools and practices Our API s are also usable from other languages for the Java Virtual Machine such as Scala Following the Java information is a section on how to write an extension in Scala Summary A NetLogo extension consists of a folder with the following contents Required e A JAR file with the same name as the extension the following contents one or more classes that implementation org nlogo api Primitive a main class that implements org nlogo api ClassManager and a NetLogo extension manifest file with the following four tags 0 Manifest Version always 1 0 0 Extension Name the name of the extension 0 Class Manager the fully qualified name of a class implementing org nlogo api ClassManager 0 NetLogo Extension API Version the version of NetLogo Extension API for which this JAR is intended If a user opens the extension with NetLogo that has a different Extension API version a warning message is issued To tell which version of the Extension API your NetLogo supports choose the About NetLogo item in the Help menu and then click on the System tab Or you can launch NetLogo jar with the extension api version argument Optional e One or more NetLogo models demonstrating how the extension is us
528. uilt in language primitives Double precision floating point math Runs are exactly reproducible cross platform e Environment View your model in either 2D and 3D Scalable and rotatable vector shapes What is NetLogo 1 NetLogo 4 1 2 User Manual Turtle and patch labels Command center for on the fly interaction Interface builder w buttons sliders switches choosers monitors text boxes notes output area Speed slider lets you fast forward your model or see it in slow motion Powerful and flexible plotting system Info tab for annotating your model HubNet participatory simulations using networked devices Agent monitors for inspecting and controlling agents Export and import functions export data save and restore state of model make a movie BehaviorSpace an open source tool used to collect data from multiple parallel runs of a model System Dynamics Modeler Experimental NetLogo 3D application allows modeling 3D worlds Headless mode allows doing batch runs from the command line e Web Models and HubNet clients can be saved as applets to be embedded in web pages note some features are not available in applets for example 3D e APls controlling API allows embedding NetLogo in a surrounding application extensions API allows adding new commands and reporters to the NetLogo language open source example extensions are included What is NetLogo Copyright and License Information
529. umber wolves create the wolves then initialize their variables L set color balck set size 1 5 easier to see set energy random 2 wolf gain from food setxy random xcor random ycor J display labels update plot end to go if not any turtles stop ask sheep move if grass set energy energy 1 deduct energy for sheep only if grass switch is on eat grass death reproduce sheep To find a fragment of code in the procedures click on the Find button in the Procedures Toolbar and the Find dialog will appear 8000 Find Find sheep Replace with wolves M ignore case M Wrap around e o e eee Replace All Replace Replace Find Previous next You may enter either a word or phrase to find or a word or phrase to find and one to replace it with The Ignore case checkbox controls whether the capitalization must be the same to indicate a match If the Wrap around checkbox is checked the entire Procedures tab will be checked for the phrase starting at the cursor position when it reaches the end it will return to the top otherwise only the area from the cursor position to the end of the Procedures tab will be searched The Next and Previous buttons will move down and up to find another occurrence of the search phrase Replace changes the currently selected phrase with the replace phrase and Replace 8 Find changes the selected phrase and moves to the next occur
530. und play sound later filename delay Plays a sound file after the specified delay in seconds It does not wait for the sound file to play or finish before moving to the next command It supports WAV AIFF and AU files 7 plays the beep wav sample file one second from now sound play sound later beep wav 1 sound start note sound start note instrument keynumber velocity Starts a note The note will continue until sound stop note sound stop instrument or sound stop music is called 7 play a violin at middle C sound start note VIOLIN 60 64 7 play a C major scale on a xylophone foreach 60 62 64 65 67 69 71 72 sound start note XYLOPHONE 65 wait 0 2 sound stop note XYLOPHONE sound stop note sound stop note instrument keynumber Stops a note 7 stop a violin note at middle C sound stop note VIOLIN 60 sound stop instrument Sound Extension 257 NetLogo 4 1 2 User Manual sound stop instrument instrument Stops all notes of an instrument 7 stop all cello notes sound stop instrument CELLO sound stop music sound stop music Stops all notes Sound names Drums 35 Acoustic Bass Drum 59 Ride Cymbal 2 36 Bass Drum 1 60 Hi Bongo 37 Side Stick 61 Low Bongo 38 Acoustic Snare 62 Mute Hi Conga 39 Hand Clap 63 Open Hi Conga 40 Electric Snare 64 Low Conga 41 Low Floor Tom 65 Hi Timbale 42 Closed Hi Hat 66 Low Timbale 43 Hi
531. urtle s pen is down all movement commands cause lines to be drawn including jump setxy and move to Note These commands are equivalent to setting the turtle variable pen mode to down up and erase Note On Windows drawing and erasing a line might not erase every pixel pen mode A This is a built in turtle variable It holds the state of the turtle s pen You set the variable to draw lines erase lines or stop either of these actions Possible values are up down and erase pen size A This is a built in turtle variable It holds the width of the line in pixels that the turtle will draw or erase when the pen is down or erasing plabel e A This is a built in patch variable It may hold a value of any type The patch appears in the view with the given value attached to it as text You can set this variable to add change or remove a patch s label All patch variables can be directly accessed by any turtle standing on the patch See also plabel color label label color plabel color Edo co x This is a built in patch variable It holds a number greater than or equal to O and less than 140 This number determines what color the patch s label appears in if it has a label You can set this variable to change the color of a patch s label All patch variables can be directly accessed by any turtle standing on the patch See also plabel label label color 392 NetLogo Dictionary NetLogo 4
532. urtle with who number 5 Local variables A local variable is defined and used only in the context of a particular procedure or part of a procedure To create a local variable use the 1et command You can use this command anywhere If you use it at the top of a procedure the variable will exist throughout the procedure If you use it inside a set of square brackets for example inside an ask then it will exist only inside those brackets to swap colors turtlel turtle2 let temp color of turtlel ask turtlel set color color of turtle2 ask turtle2 set color temp end NetLogo represents colors in different ways First as numbers in the range 0 to 140 with the exception of 140 itself Below is a chart showing the range of colors you can use in NetLogo Programming Guide 97 NetLogo 4 1 2 User Manual black 0 white 9 9 gray 5 8 9 9 9 red 15 om 19 199 orange 25 28 29 299 brown 35 E 38 39 399 yellow 45 48 49 499 green 55 58 59 59 9 lime 65 68 69 69 9 turquoise 75 78 79 79 9 cyan 85 88 89 89 9 sky 95 98 99 99 9 blue 105 108 109 109 9 violet 115 38 119 1199 magenta 125 128 129 1299 pink 135 137 138 139 139 9 The chart shows that e Some of the colors have names You can use these names in your code e Every named color except black and white has a number ending in 5 e On either side of each named color are darker and lighter shades of the color e O is pure black 9 9 is pu
533. urtles procedure does e ask turtles says that each turtle should run the commands in the brackets e right random 360 is another command that uses a reporter First each turtle picks a random whole number between 0 and 359 random doesn t include the number you give it as a possible result Then the turtle turns right this number of degrees e forward 1 makes the turtle move forward one step Why couldn t we have just written all of these commands in go instead of in a separate procedure We could have but during the course of building your project it s likely that you ll add many other paris We d like to keep go as simple as possible so that it is easy to understand Eventually it will include many other things you want to have happen as the model runs such as calculating something or plotting the results Each of these things to do will have its own procedure and each procedure will have its own unique name The go button you made in the Interface tab is a forever button meaning that it will continually run its commands until you shut it off by clicking on it again After you have pressed setup once to create the turtles press the go button Watch what happens Turn it off and you ll see that all the turtles stop in their tracks Note that if a turtle moves off the edge of the world it wraps that is it appears on the other side This is the default behavior It can be changed see the Topology section of the Pro
534. ush in a single direction to make a tree set default shape turtles circle ert 5 ask turtle 0 create link with turtle 1 create link with turtle 2 ask turtle 1 create link with turtle 3 create link with turtle 4 layout with a fairly strong SOUTH magnetic field repeat 50 __layout magspring turtles with who 0 links 0 3 4 1 50 5 false end layout radial 366 NetLogo Dictionary NetLogo 4 1 2 User Manual layout radial turtle set link set root agent Arranges the turtles in turtle set connected by links in ink set in a radial tree layout centered around the root agent which is moved to the center of the world view Only links in the link set will be used to determine the layout If links connect turtles that are not in turtle set those turtles will remain stationary Even if the network does contain cycles and is not a true tree structure this layout will still work although the results will not always be pretty to make a tree set default shape turtles circle crt 6 ask turtle 0 create link with turtle 1 create link with turtle 2 create link with turtle 3 ask turtle 1 create link with turtle 4 create link with turtle 5 do a radial tree layout centered on turtle 0 layout radial turtles links turtle 0 end layout spring layout spring turtle set link set spring constant spring length repulsion constant Arranges the turtles in turtle set as if the links in
535. ust have the same dimensions matrix inverse matrix inverse matrix Reports the inverse of the given matrix or results in an error if the matrix is not invertible matrix transpose matrix transpose matrix Reports the transpose of the given matrix 248 Matrix Extension NetLogo 4 1 2 User Manual matrix real eigenvalues matrix real eigenvalues matrix Reports a list containing the real eigenvalues of the given matrix matrix imaginary eigenvalues matrix imaginary eigenvalues matrix Reports a list containing the imaginary eigenvalues of the given matrix matrix eigenvectors matrix eigenvectors matrix Reports a matrix that contains the eigenvectors of the given matrix Each eigenvector as a column of the resulting matrix matrix det matrix det matrix Reports the determinant of the matrix matrix rank matrix rank matrix Reports the effective numerical rank of the matrix obtained from SVD Singular Value Decomposition matrix cond matrix cond matrix Reports the matrix condition 2 norm which is the ratio of largest to smallest singular value obtained from SVD matrix trace matrix trace matrix Reports the trace of the matrix which is simply the sum of the main diagonal elements Advanced features Matrix Extension 249 NetLogo 4 1 2 User Manual matrix solve matrix solve A C Reports the solution to a linear system of equations specified by the A and C matrices In general solving a set of linear equations
536. ust like a turtle or patch while turtles and patches are constrained to be inside the world the Observer can be anywhere Like a turtle the Observer has a heading pitch and roll these variables control where the Observer is looking that is what you see in the View e Move to the 3D View and make sure Orbit is selected in the bottom left corner of the view e Click and hold the mouse button in the middle of the view move the mouse left right up and down How does the position and orientation of the Observer change e Press the reset perspective button in the lower right corner of the view and select Zoom in the lower left corner e Click and hold the mouse button in the middle of the view and move the mouse up and down Which of the Observer variables change Which stay the same e Try rotating the world a bit and then zoom again e Press the Move button in the lower left corner of the view e Click and hold the mouse button in the middle of the view and move the mouse up down left and right How does the view change How do the Observer variables change After you are done exploring the world using the mouse controls you can take a look at the Observer control buttons in the lower left portion of the interface If you are familiar the latest versions of NetLogo you should be familiar with the first three buttons in the Observer group Watch follow and ride are special modes that automatically update the positio
537. utput without changing the outcome of a model Example yj Run 1 random seed 50 setup repeat 10 go Run 2 random seed 50 setup with local randomness watch one of turtles repeat 10 go Since one of is used inside with 1ocal randomness both runs will be identical Specifically how it works is the state of the random number generator is remembered before the commands run then restored afterwards If you want to run the commands with a fresh random state instead of the same random state that will be restored later you can begin the commands with random seed new seed The following example demonstrates that the random number generator state is the same both before the commands run and afterwards random seed 10 with local randomness print n values 10 random 10 7 prints 8 984245 47 9 print n values 10 random 10 77 prints 89 8 4 2 4 5 4 7 9 without interruption without interruption commands The agent runs all the commands in the block without allowing other agents using ask concurrent to interrupt That is other agents are put on hold and do not run any commands until the commands in the block are finished Note This command is only useful in conjunction with ask concurrent See also ask concurrent 428 NetLogo Dictionary NetLogo 4 1 2 User Manual word word value1 value2 word value Concatenates the inputs together and reports the result as a string show
538. utput you need by some other means such as exporting world files or writing to a text file Yet another example java server Xmx1024M cp NetLogo jar org nlogo headless Main model Fire nlogo N xperiment experiment2 table table output csv spreadsheet spreadsheet output csv The optional table lt filename gt argument specifies that output should be generated in a table format and written to the given file as CSV data If is specified as the filename than the output is sent to the standard system output stream Table data is written as it is generated with each complete run The optional spreadsheet lt filename gt argument specified that spreadsheet output should be generated and written to the given file as CSV data If is specified as the filename than the output is sent to the standard system output stream Spreadsheet data is not written out until all runs in the experiment are finished Note that it is legal to specify both table and spreadsheet and if you do both kinds of output file will be generated Here is one final example that shows how to run an experiment setup which is stored in a separate XML file instead of in the model file java server Xmx1024M cp NetLogo jar org nlogo headless Main model Fire nlogo N setup file fire setups xml xperiment experiment 3 If the XML file contains more than one experiment setup it is necessary to use the experiment ar
539. uture versions While we ve made efforts to ensure a quality product the preview has not been subject to the same rigorous quality control processes as 2D NetLogo e Introduction e Tutorial e FAQ e Dictionar Introduction To get started using NetLogo 3D launch the NetLogo 3D application and check out the Sample Models in the 3D section of the Models Library On Windows the NetLogo installer doesn t add a NetLogo 3D shortcut to your Start menu You ll find the NetLogo 3D icon in the folder where you installed NetLogo which is usually under Program Files When you re ready to write your own 3D model look at the Code Examples in the 3D section of the Models Library Turtle Perspective Example 3D helps you learn about the different perspectives Turtle and Observer Motion Example 3D helps you understand how turtles and the Observer move in 3D You can also step through this model with the tutorial below 3D Worlds An unspeakable horror seized me There was a darkness then a dizzy sickening sensation of sight that was not like seeing saw a Line that was no Line Space that was not Space was myself and not myself When could find voice shrieked loud in agony Either this is madness or it is Hell It is neither calmly replied the voice of the Sphere it is Knowledge it is Three Dimensions open your eye once again and try to look steadily Edwin A Abbott from Flatland A romance in many dimensions In 3D the
540. ven line thickness around the edges The data may consist either of an entire VectorDataset or a single VectorFeature For point data it fills a circle with a radius equal to the line thickness gis paint gis paint RasterDataset transparency Paints the given raster data to the NetLogo drawing layer The highest value in the dataset is painted white the lowest is painted in black and the other values are painted in shades of gray scaled linearly between white and black The transparency input determines how transparent the new image in the drawing will be Valid inputs range from O completely opaque to 255 completely transparent gis import wms drawing gis import wms drawing server url spatial reference layers transparency Imports an image into the NetLogo drawing layer using the Web Mapping Service protocol as defined by the Open Geospatial Consortium The spatial reference and layers inputs should be given as strings The spatial reference input corresponds to the SRS parameter to the GetMap request as defined in section 7 2 3 5 of version 1 1 1 ofthe WMS standard The layers input corresponds to the LAYERS parameter to the as defined in 7 2 3 3 of version 1 1 1 of the WMS standard You can find the list of valid spatial reference codes and layer names by examining the response to GIS Extension 297 NetLogo 4 1 2 User Manual a GetCapabilities request to the WMS server Consult the relevant standard for instructions on how to
541. ven string The file should be in the format used by the export world primitive Note that the functionality of this primitive is also directly available from NetLogo s File menu When using import world to avoid errors perform these steps in the following order 1 Open the model from which you created the export file 2 Press the Setup button to get the model in a state from which it can be run 3 Import the file 4 Re open any files that the model had opened with the file open command 5 If you want press Go button to continue running the model from the point where it left off If you wish to import a file from a location other than the model s location you may include the full path to the file you wish to import See export world for an example in cone agentset in cone distance angle This reporter lets you give a turtle a cone of vision in front of itself The cone is defined by the two inputs the vision distance radius and the viewing angle The viewing angle may range from 0 to 360 and is centered around the turtle s current heading If the angle is 360 then in cone is equivalent to in radius in cone reports an agentset that includes only those agents from the original agentset that fall in the cone This can include the agent itself 360 NetLogo Dictionary NetLogo 4 1 2 User Manual The distance to a patch is measured from the center of the patch ask turtles ask patches in cone 3 60 set pcolor red
542. verything 8 Press the setup button In the view you will see pink and blue lines with numbers 10 15 13 12 18 14 15 18 17 These lines represent mingling groups at a party Men are represented in blue women in pink The numbers are the total number of people in each group Do all the groups have about the same number of people Do all the groups have about the same number of each sex Let s say you are having a party and invited 150 people You are wondering how people will gather together Suppose 10 groups form at the party How do you think they will group Instead of asking 150 of your closest friends to gather and randomly group let s have the computer simulate this situation for us What to do 1 Press the go button Pressing go again will stop the model manually 2 Observe the movement of people until the model stops 3 Watch the plots to see what s happening in another way Now how many people are in each group Originally you may have thought 150 people splitting into 10 groups would result in about 15 people in each group From the model we see that people did not divide up evenly into the 10 groups instead some groups became very small whereas other groups became very large Also the party changed over time from all mixed groups of men and women to all single sex groups What could explain this There are lots of possible answers to this question about what happens at real parties The
543. ways to open a turtle monitor besides right clicking or control clicking depending on your operating system One way is to choose Turtle Monitor from the Tools menu then type the who number of the turtle you want to inspect into the who field and press return The other way is to type inspect turtle 0 or other who number into the Command Center You close a turtle monitor by clicking the close box in the upper left hand corner Macintosh or upper right hand corner other operating systems Now that we know more about Agent Monitors we have three ways to change an individual turtle s color One way is to use the box called an Agent Commander found at the bottom of an Agent Monitor You type commands here just like in the Command Center but the commands you type here are only done by this particular turtle e In the Agent Commander of the Turtle Monitor for turtle O type set color pink What happens in the View Did anything change in the Turtle Monitor A second way to change one turtle s color is to go directly to the color variable in the Turtle Monitor and change the value e Select the text to the right of color in the Turtle Monitor e Type in a new color such as green 2 What happened The third way to change an individual turtle s or patch s color is to use the observer Since the observer oversees the NetLogo world it can give commands that affect individual turtles as well as groups of turtles
544. will also override any previous set burst mode calls 7 so there will be no new burst mode data for sensors 1 2 and 3 gogo set output port power gogo set output port power power level Sets the power level of the active output ports power levelis a number between 0 off and 7 full power The output ports affected by this command are determined by the gogo talk to output ports command Note that for many practical applications it is more efficient to use mechanical devices such as gears and pulleys to control the torque of motors Example gogo talk to motors a b er nar gogo set motor power 4 5 will lower the power of all output ports by half of the full power gogo stop burst mode gogo stop burst mode Turns off burst mode for all sensors See also gogo burst value and gogo set burst mode NetLogoLab and the GoGo Board Extension 273 NetLogo 4 1 2 User Manual 274 NetLogoLab and the GoGo Board Extension Profiler Extension The profiler extension provides information which may help you make your model run faster It consists of a set of primitives for measuring how many times the procedures in your model are called during a run and how long each call takes Caution The profiler extension is new and experimental It is not yet well tested or user friendly Nonetheless we think some users will find it useful Usage The profiler extension comes preinstalled To use the extension in your model add
545. x Ed Asks the observer to watch this agent See also watch while while reporter commands If reporter reports false exit the loop Otherwise run commands and repeat The reporter may have different values for different agents so some agents may run commands a different number of times than other agents while any other turtles here fd 1 7 turtle moves until it finds a patch that has 7 no other turtles on it who who x This is a built in turtle variable It holds the turtle s who number or ID number an integer greater than or equal to zero You cannot set this variable a turtle s who number never changes Who numbers start at 0 A dead turtle s number will not be reassigned to a new turtle until you use the clear turtles or clear all commands at which time who numbering starts over again at 0 Example show who of turtles with color red 7 prints a list of the who numbers of all red turtles in the Command Center in random order crt 100 ifelse who lt 50 set color red set color blue 7 turtles 0 through 49 are red turtles 50 7 through 99 are blue 426 NetLogo Dictionary NetLogo 4 1 2 User Manual You can use the turtle reporter to retrieve a turile with a given who number See also turtle with agentset with reporter Takes two inputs on the left an agentset usually turtles or patches On the right a boolean reporter Reports a new agentset containin
546. xceptions set forth below You may reproduce and distribute the portions of Software identified below each a Redistributable provided that you comply with the following note that You may be entitled to reproduce and distribute other portions of the Software not defined here as a Redistributable under certain other licenses as described in the THIRDPARTYLICENSEREADME a You distribute the Redistributable complete and unmodified and only bundled as part of Your applets and applications Programs b You do not distribute additional software intended to replace any component s of the Redistributable c You do not remove or alter any proprietary legends or notices contained in or on the Redistributable d You only distribute the Redistributable subject to a license agreement that protects Sun s interests consistent with the terms contained in the Software License Agreement and e You agree to defend and indemnify Sun and its licensors from and against any damages costs liabilities settlement amounts and or expenses including attorneys fees incurred in connection with any claim lawsuit or action by any third party that arises or results from the use or distribution of any and all Programs and or Redistributable Apache Commons Codec Copyright 2001 2008 The Apache Software Foundation Licensed under the Apache License Version 2 0 the License you may not use this file except in compliance with the License You may obt
547. ximum x coordinate for patches minimum y coordinate for patches max pycor 16 maximum y coordinate for patches 16 16 16 16 Torus 33 x 33 minimum z coordinate for patches Y Y Y A max pzcor 16 ds maximum z coordinate for patches v W View Patch size 13 Font size 10 measured in pixels of labels on agents Y Turtle shapes ifunchecked turtles appear as squares Y Smooth edges slower only affects 3D view M Show wire frame only affects 3D view Tick counter Y Show tick counter Tick counter label ticks Cancel Apply 0K The z axis is perpendicular to both the x axis and the y axis when you reset perspective itis the axis that comes straight out of the screen In the default position max pzcor is the face of the cube nearest to you and min pzcor is the face farthest from you As always min pxcor is on the left max pxcor on the right min pycor on the bottom and max pycor on the top You ll also notice on the left side of the Model Settings that there are options for wrapping in all three directions however they are all checked and grayed out Topologies are not yet functional in NetLogo 3D so all worlds wrap in all three directions e Move to the Command Center and type print count patches Is the number smaller or larger than you expected In a 3D World the number of patches grows very quickly since count patches world width 212 Introducing NetLogo 3
548. y appear to take up space because they have a shape Wrapping also affects how the view looks when you are following a turtle On a torus wherever the turtle goes you will always see the whole world around it 128 Programming Guide NetLogo 4 1 2 User Manual da 1 2 A0 2 a ye 2 2 1 2 2 2 r2 2 31 1 0 1 1 1 2 1 72 1 1 0 0 0 1 0 cos 2 0 1 1 0 1 1 1 2 1 2 1 Whereas in a box or cylinder the world has edges so the areas past those edges show up in the view as gray 1 1 0 1 1 0 0 0 1 1 Q 1 1 1 Code Example Termites Perspective Demo torus Ants Perspective Demo box Instead of 3 0 s settings that only control the appearance of wrapping in the view NetLogo 3 1 has settings that control whether the world actually wraps or not that is whether opposite edges are in fact connected These new wrapping settings determine the world topology that is whether the world is a torus box or cylinder This affects the behavior and not just the visual appearance of the model In the past model authors were required to write extra code to simulate a box world with the aid of special no wrap primitives No wrap versions were provided for distance xy in radius in cone face xy and towards xy In 3 1 the special no wrap versions are no longer necessary Instead the topology controls whether the primitives wrap or not They always use the shortes
549. y turtles patches procedures buttons and so o cani my model contain ie 309 Can use GIS data in Neth0g0 ccccsssssssecceeeessssssssecceesesssseeeesssseseesesesseessseeteses 309 My model runs slowly How can speed iu occoooonococcccccnonccononannnnnnnnccccnnnnnnoncnnnnnnnnns 310 Can have more than one model open ata time 310 Can change the choices in a chooser on the fly 310 Can divide the code for my model up into several files2 rrenen enerne 310 Programming acicate aida 310 How is the NetLogo language different from the StarLogo and StarLogoT languages How do convert my StarLogo or StarLogoT model to NetLogo 310 How does the NetLogo language differ from other Log0sSP ocooooccccncccccnococonoccnoncccnananono 311 xiv NetLogo 4 1 2 User Manual Table of Contents FAQ Frequently Asked Questions How come my model from an earlier NetLogo doesn t work right oooo ooocccccccnnnnno 311 Why does my code have strange characters init eee 311 How do take the negative of a nuMber ccccccnnnnococcccncccnonnnononcnnnnnnccnnnnnnnnnnnnnncncnannnnns 311 My turtle moved forward 1 but it s still on the same patch WhY ccccccnnnnccocncncncnnon 311 How do keep my turtles on patch Centers cccoononococcccnoccnonnnononncnnnnnncnnonannnonnnnncnnnanannns 312 patch ahead 1 is reporting the same patch my turtle is already standing on Why 312 How do give my turtles
550. you may wish to use some method of generating fresh names Examples export world user new file export world word results date and time csv export world word results random float 1 0 csv extensions extensions name Allows the model to use primitives from the extensions with the given names See the Extensions guide for more information extract hsb extract hsb color Reports a list of three values in the range 0 to 255 representing the hue saturation and brightness respectively of the given NetLogo color in the range 0 to 140 not including 140 itself show extract hsb red gt 2 198 206 372 215 show extract hsb cyan gt 127 5 145 714 196 See also approximate hsb approximate rgb extract rgb extract rgb 342 NetLogo Dictionary NetLogo 4 1 2 User Manual extract rgb color Reports a list of three values in the range 0 to 255 representing the levels of red green and blue respectively of the given NetLogo color in the range 0 to 140 not including 140 itself show extract rgb red gt 215 50 41 show extract rgb cyan gt 84 196 196 See also approximate rgb approximate hsb extract hsb F face face agent Set the caller s heading towards agent If wrapping is allowed by the topology and the wrapped distance around the edges of the world is shorter face will use the wrapped path If the caller and the agent are at the exact same position the caller s
551. yourself in case you get lost It s easy to do To look at the world from a different angle press the rotate button click and drag the mouse up down left or right The observer will continue to face the same point as before where the blue cross is but its position in the relation to the xy plane will change To move closer or farther away from the world or the agent you are watching following or riding press the zoom button and drag up and down along the 3D View Note when you are in follow or ride mode zooming will switch you between ride and follow since ride is just a special case of follow where the distance at which you are following is 0 To change the position of the observer without changing the direction it is facing select the move button and drag the mouse up down left and right inside the 3D View while holding down the mouse button To allow the mouse position and state to be passed to the model select the interact button and it will function just as the mouse does in the 2D view To return the observer and focus point to their default positions press the Reset Perspective button or use the reset perspective command Fullscreen Mode To enter fullscreen mode press the Full Screen button to exit fullscreen mode press the Esc key Note Fullscreen mode doesn t work on some computers It depends on what kind of graphics card you have See the System Requirements for details 3D Shapes Some s
552. ype is a popup menu that initially says observer gt You can choose either observer turtles or patches to specify which agents run the command you type Tip a quicker way to change between observer turtles and patches is to use the tab key on your keyboard Accessing previous commands After you type a command it appears in the large scrolling box above the command line You can use Copy on the Edit menu in this area to copy commands and then paste them elsewhere such as the Procedures tab You can also access previous commands using the history popup menu which is the small downward pointing triangle to the right of where you type commands Click on the triangle and a menu of previously typed commands appears so you can pick one to use again Tip a quicker way to access previous commands is with the up and down arrow keys on your keyboard Clearing To clear the large scrolling area containing previous commands and output click clear in the top right corner To clear the history popup menu choose Clear History on that menu Arranging You can hide and show the command center using the Hide Command Center and Show Command Center items on the Tools menu To resize the command center drag the bar that separates it from the model interface Or click one of the little arrows on the right end of the bar to make the command center either very big or hidden altogether To switch between a vertical command center and a hor
553. ystem to system depending on the capabilities of the underlying Java Virtual Machine show date and time gt 01 19 36 685 PM 19 Sep 2002 die die ae The turtle or link dies if xcor gt 20 die 5 all turtles with xcor greater than 20 die ask links with color blue die all the blue links will die NetLogo Dictionary 335 NetLogo 4 1 2 User Manual See also clear turtles clear links diffuse diffuse patch variable number Tells each patch to give equal shares of number 100 percent of the value of patch variable to its eight neighboring patches number should be between O and 1 Regardless of topology the sum of patch variable will be conserved across the world If a patch has fewer than eight neighbors each neighbor still gets an eighth share the patch keeps any leftover shares Note that this is an observer command only even though you might expect it to be a patch command The reason is that it acts on all the patches at once patch commands act on individual patches diffuse chemical 0 5 7 each patch diffuses 50 of its variable 7 Chemical to its neighboring 8 patches Thus each patch gets 1 8 of 50 of the chemical from each neighboring patch diffuse4 diffuse4 patch variable number ig Like diffuse but only diffuses to the four neighboring patches to the north south east and west not to the diagonal neighbors diffuse4 chemical 0 5 each patch diffu
554. ze performance for server type applications we recommend this flag for best performance in most situations Note the use of xmx to specify a maximum heap size of one gigabyte If you don t specify a maximum heap size you will get your VM s default size which may be unusably small One gigabyte is an arbitrary size which should be more than large enough for most models you can specify a different limit if you want The required mode1 argument is used to specify the model file you want to open The experiment argument is used to specify the name of the experiment you want to run At the time you create an experiment setup in the GUI you assign it a name Here s another example that shows some additional optional arguments java server Xmx1024M cp NetLogo jar org nlogo headless Main model Fire nlogo N xperiment experiment2 max pxcor 100 min pxcor 100 max pycor 100 N min pycor 100 Note the use of the optional max pxcor max pycor etc arguments to specify a different world size than that saved in the model It s also possible for the experiment setup to specify values for the world dimensions if they are specified by the experiment setup then there is no need to specify them on the command line BehaviorSpace Guide 167 NetLogo 4 1 2 User Manual Since neither table nor spreadsheet is specified no results will be generated This is useful if the experiment setup generates all the o

NetLogo 4.1.2 User Manual - Center for Human Science

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