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1. Examples w 2 q floor tan pi 2 0 1 f x sin w x sinc x sin pi x pi x delta t t 0 ramp t t gt 0 t 0 min a b a lt b a b comb n k n k n k len3d x y z sqrt x xty y z z plot f x sin x a a 0 2 f x a 0 4 f x Note that the variable pi is already defined But it is in no way magic you may redefine it to be whatever you like Valid names are the same as in most programming languages they must begin with a letter but subsequent characters may be letters digits or _ Note however that the fit mechanism uses several variables with names that begin FIT_ It is safest to avoid using such names FIT_LIMIT however is one that you may wish to redefine See the documentation on fit for details See show functions show variables and fit 11 Glossary Throughout this document an attempt has been made to maintain consistency of nomenclature This cannot be wholly successful because as gnuplot has evolved over time certain command and keyword names have been adopted that preclude such perfection This section contains explanations of the way some of these terms are used A page or screen is the entire area addressable by gnuplot On a monitor it is the full screen on a plotter it is a single sheet of paper A screen may contain one or more plots A plot is defined by an abscissa and an ordinate although these need not actually appear on it as well as the m
2. The text itself may be anything LaTeX can typeset as an LR box rule s may help for best positioning Examples About label positioning Use gnuplot defaults mostly sensible but sometimes not really best set title LaTeX gamma Force centering both horizontally and vertically set label LaTeX gamma at 0 0 Specify own positioning top here set xlabel t LaTeX gamma The other label account for long ticlabels set ylabel r LaTeX gamma rule 7mm Opt 34 49 64 Unixpc The unixpc terminal driver supports AT amp T 3b1 and AT amp T 7300 Unix PC It has no options 34 49 65 Unixplot The unixplot terminal driver generates output in the Unix plot graphics language It has no options This terminal cannot be compiled if the GNU version of plot is to be used in that case use the gnugraph terminal instead 34 49 66 Vx384 The vx384 terminal driver supports the Vectrix 384 and Tandy color printers It has no options 34 49 67 VWS The VWS terminal driver supports the VAX Windowing System It has no options It will sense the display type monochrome gray scale or color All line styles are plotted as solid lines 34 49 68 Windows Three options may be set in the windows terminal driver Syntax set terminal windows lt color gt lt fontname gt lt fontsize gt where lt color gt is either color or monochrome lt fontname gt
3. 23 24 20 4 TRAN BES 2000 we koe ee ee EE A a a a Bok ko es 3 Goal a a 31 2658 Tilo a aaa o dd A a de A A A A AAA 32 26 6 Wath 200 A E E A nl ts ees 33 27 Print 34 28 Pwd 34 29 Quit 35 30 Replot 35 31 Reread 35 32 Reset 36 33 Save 36 34 Set show 36 341 Amelie a eee A A A a GA e ee 37 BAD ATEO W 2 aii ds 8 ES RR td ON Ree oe EA Ape Mee 37 A E A ON ye a et 38 34 3 1 Parametric mode 39 34 3 2 Polar mode tia a RR AA 39 LAB 2 2 a A A A Oe a ee ka 40 34 5 A sac hb BM RO oe EE ob ee oa eS 40 34 6 Border ir Ue de de ds Shea eee Rds ey a A de or bls be di oe and 40 34 7 BOX WILD o al a E A AA a a ee a bE 41 G48 Cla bels e et won BS a eg E e e Meili lh Biel Boh he Be ee 41 SA A O aS es Wheat ed ok indie ds oh de BOMB Not ths Math en tee thy the Sheet aya eR Be 42 JA LOC nur parani uti hak hy bf hi bts A A gl a ae a HA ahs 42 BATIA OnTOUT ont de Bite te te ine amp ot BS tada lo Lo fo SR Re iow a 43 34 1 2 Data styles a eee A A Se Pe aie ee eo OR e E Bed 44 S413 Denda Ak AA e Pd e ee es Bod el Geen be oa BS wh State 44 34714 Dummy A ee OB ed a eee ee Pat a mee ee eee a aS 45 34 15 Encoding sue 6 tet S Pe AN A ac a a a SEE RSS 46 34 16 ROLM AT Vs Sai Ge Gh he AE AE AE AE RES SIS hk tA eh dd e e A SS e elo Eras 46 94 16 1 Format specifiers a a a nce a a ee a ee a e i 46 34 16 2 Time date Specifiers o ee ee 47 34 17 Functiomstyle 043 5 4 5 ada HES Bee A a eh ea 48 SASS Functions orde ee a ee be
4. Syntax fit xrange yrange lt function gt lt datafile gt datafile modifiers via lt parameter file gt lt vari gt f lt var2 gt Ranges may be specified to temporarily limit the data which is to be fitted any out of range data points are ignored The syntax is dummy_variable lt min gt lt max gt analogous to plot see plot ranges lt function gt is any valid gnuplot expression although it is usual to use a previously user defined function of the form f x or f x y lt datafile gt is treated as in the plot command All the plot datafile modifiers using every except smooth are applicable to fit See plot datafile The default data formats for fitting functions with a single independent variable y f x are x y or x y s those formats can be changed with the datafile using qualifier The third item a column number or an expression if present is interpreted as the standard deviation of the corresponding y value and is used to compute a weight for the datum 1 s 2 Otherwise all data points are weighted equally with a weight of one 17 To fit a function with two independent variables z f x y the required format is using with four items x y z s The complete format must be given no default columns are assumed for a missing token Weights for each data point are evaluated from s as above If error estimates are not available a constant value can be specifie
5. abcd 1 2 quoted 2 will display pO0 abcd p1 1 2 p2 p3 quoted p4 p5 p6 2 p7 xx NOTE there is a clash in syntax with the datafile using callback operator Use n or column n to access column n from a datafile inside a called datafile plot 16 19 Clear The clear command erases the current screen or output device as specified by set output This usually generates a formfeed on hardcopy devices Use set terminal to set the device type For some terminals clear erases only the portion of the plotting surface defined by set size so for these it can be used in conjunction with set multiplot to create an inset Example set multiplot plot sin x set origin 0 5 0 set size 0 4 0 4 clear plot cos x set nomultiplot 5 Please see set multiplot set size and set origin for details of these commands 20 Exit The commands exit and quit and the END OF FILE character will exit the current gnuplot command file and load the next one See help batch interactive for more details Each of these commands will clear the output device as does the clear command before exiting 21 Fit The fit command can fit a user defined function to a set of data points x y or x y z using an im plementation of the nonlinear least squares NLLS Marquardt Levenberg algorithm Any user defined variable occurring in the function body may serve as a fit parameter but the return type of the function must be real
6. load filename cd dir although there are some subtle differences see syntax for more details Any command line arguments are assumed to be names of files containing gnuplot commands with the exception of standard X11 arguments which are processed first Each file is loaded with the load command in the order specified gnuplot exits after the last file is processed When no load files are named gnuplot enters into an interactive mode The special filename is used to denote standard input See help batch interactive for more details Many gnuplot commands have multiple options These options must appear in the proper order although unwanted ones may be omitted in most cases Thus if the entire command is command a b c then command ac will probably work but command c a will fail Commands may extend over several input lines by ending each line but the last with a backslash The backslash must be the last character on each line The effect is as if the backslash and newline were not there That is no white space is implied nor is a comment terminated Therefore commenting out a continued line comments out the entire command see comment But note that if an error occurs somewhere on a multi line command the parser may not be able to locate precisely where the error is and in that case will not necessarily point to the correct line In this document curly braces denote optional arguments and a vertical bar
7. Specifying FIT START_LAMBDA as zero or less will re enable the automatic selection The variable FIT_LAMBDA_FACTOR 21 gives the factor by which lambda is increased or decreased whenever the chi squared target function increased or decreased significantly Setting FIT_LAMBDA_FACTOR to zero re enables the default factor of 10 0 Oher variables with the FIT_ prefix may be added to fit so it is safer not to use that prefix for user defined variables The variables FIT_SKIP and FIT_INDEX were used by earlier releases of gnuplot with a fit patch called gnufit and are no longer available The datafile every modifier provides the functionality of FIT_SKIP FIT_INDEX was used for multi branch fitting but multi branch fitting of one independent variable is now done as a pseudo 3D fit in which the second independent variable and using are used to specify the branch See fit multi branch 21 4 2 Environment variables The environment variables must be defined before gnuplot is executed how to do so depends on your operating system FIT_LOG changes the name and or path of the file to which the fit log will be written from the default of fit log in the working directory FIT_SCRIPT specifies a command that may be executed after an user interrupt The default is replot but a plot or load command may be useful to display a plot customized to highlight the progress of the fit 21 5 Multi branch In multi branch fitting multiple d
8. accepts several numerical specifications but gnuplot requires all inputs to be double precision floating point variables so 1f is the only permissible specifier scanf expects to see white space a blank tab Xt newline An or formfeed Af between numbers anything else in the input stream must be explicitly skipped Note that the use of t n or f or requires use of double quotes rather than single quotes Examples This creates a plot of the sum of the 2nd and 3rd data against the first The format string specifies comma rather than space separated columns plot file using 1 2 3 1f 1f 1 In this example the data are read from the file MyData using a more complicated format plot MyData using 1 41f 20 7 n 41 The meaning of this format is lf ignore a number Alf read a double precision number x by default 20 n ignore 20 non newline characters Alf read a double precision number y by default One trick is to use the ternary operator to filter data plot file using 1 3 gt 10 2 1 0 which plots the datum in column two against that in column one provided the datum in column three exceeds ten 1 0 is undefined gnuplot quietly ignores undefined points so unsuitable points are suppressed In fact you can use a constant expression for the column number provided it doesn t start with an opening parenthesis constructs like using O complic
9. separates mutually exclusive choices gnuplot keywords or help topics are indicated by backquotes or boldface where available Angle brackets lt gt are used to mark replaceable tokens In many cases a default value of the token will be taken for optional arguments if the token is omitted but these cases are not always denoted with braces around the angle brackets For on line help on any topic type help followed by the name of the topic or just help or to get a menu of available topics The new gnuplot user should begin by reading about plotting if on line type help plotting 3 Seeking assistance There is a mailing list for gnuplot users Note however that the newsgroup comp graphics apps gnuplot is identical to the mailing list they both carry the same set of messages We prefer that you read the messages through the newsgroup rather than subscribing to the mailing list Administrative requests should be sent to majordomo dartmouth edu Send a message with the body not the subject consisting of the single word help without the quotes for more details The address for mailing to list members is info gnuplot dartmouth edu Bug reports and code contributions should be mailed to bug gnuplot dartmouth edu The list of those interested in beta test versions is info gnuplot betaldartmouth edu There is also a World Wide Web page with up to date information including known bugs http www cs dartmouth edu gn
10. width lt width_increment gt title lt text gt no box linestyle ls lt line_style gt linetype 1t lt line_type gt linewidth lw lt line_width gt set nokey show key By default the key is placed in the upper right corner of the graph The keywords left right top bottom outside and below may be used to place the key in the other corners inside the graph or to the right outside or below the graph They may be given alone or combined 52 Justification of the labels within the key is controlled by Left or Right default is Right The text and sample can be reversed reverse and a box can be drawn around the key box in a spec ified linetype and linewidth or a user defined linestyle Note that not all terminal drivers support linewidth selection though The length of the sample line can be controlled by samplen The sample length is computed as the sum of the tic length and lt sample_length gt times the character width samplen also affects the positions of point samples in the key since these are drawn at the midpoint of the sample line even if it is not drawn lt sample_length gt must be an integer The vertical spacing between lines is controlled by spacing The spacing is set equal to the product of the pointsize the vertical tic size and lt vertical_spacing gt The program will guarantee that the vertical spacing is no smaller than the character height The lt width_increment gt is a
11. After help for the requested topic is given a menu of subtopics is given help for a subtopic may be requested by typing its name extending the help request After that subtopic has been printed the request may be extended again or you may go back one level to the previous topic Eventually the gnuplot command line will return If a question mark is given as the topic the list of topics currently available is printed on the screen 23 If The if command allows commands to be executed conditionally Syntax if lt condition gt lt command line gt lt condition gt will be evaluated If it is true non zero then the command s of the lt command line gt will be executed If lt condition gt is false zero then the entire lt command line gt is ignored Note that use of to allow multiple commands on the same line will not end the conditionalized commands Examples pi 3 if pi acos 1 print Fixing pi pi acos 1 print pi will display Fixing pi 3 14159265358979 but if 1 2 print Never see this print Or this either will not display anything See reread for an example of how if and reread can be used together to perform a loop 24 Load The load command executes each line of the specified input file as if it had been typed in interactively Files created by the save command can later be loaded Any text file containing valid commands can be created and then executed by the load command File
12. e g set y2label The default positions of the axis labels are as follows 104 xlabel The x axis label is centered below the bottom axis ylabel The position of the y axis label depends on the terminal and can be one of the following three positions 1 Horizontal text flushed left at the top left of the plot Terminals that cannot rotate text will probably use this method If set x2tics is also in use the ylabel may overwrite the left most x2tic label This may be remedied by adjusting the ylabel position or the left margin 2 Vertical text centered vertically at the left of the plot Terminals that can rotate text will probably use this method 3 Horizontal text centered vertically at the left of the plot The EEPIC LaTeX and TPIC drivers use this method The user must insert line breaks using to prevent the ylabel from overwriting the plot To produce a vertical row of characters add between every printing character but this is ugly zlabel The z axis label is centered along the z axis and placed in the space above the grid level y2label The y2 axis label is placed to the right of the y2 axis The position is terminal dependent in the same manner as is the y axis label x2label The x2 axis label is placed above the top axis but below the plot title It is also possible to create an x2 axis label by using new line characters to make a multi line plot title e g set title This is the title n nThis is the x2
13. graph area will be the largest rectangle of aspect ratio lt r gt that will fit into the specified portion of the output leaving adequate margins of course square is a synonym for ratio 1 Both noratio and nosquare return the graph to the default aspect ratio of the terminal but do not return lt xscale gt or lt yscale gt to their default values 1 0 ratio and square have no effect on 3 d plots set size is relative to the default size which differs from terminal to terminal Since gnuplot fills as much of the available plotting area as possible by default it is safer to use set size to decrease the size of a plot than to increase it See set terminal for the default sizes On some terminals changing the size of the plot will result in text being misplaced Examples To set the size to normal size use set size 1 1 To make the graph half size and square use set size square 0 5 0 5 To make the graph twice as high as wide use set size ratio 2 34 47 Style Default styles are chosen with the set function style and set data style commands See plot with for information about how to override the default plotting style for individual functions and data sets Syntax set function style lt style gt set data style lt style gt show function style show data style The types used for all line and point styles i e solid dash dot color etc for lines circles squares crosses etc for points will be either those
14. judged on the basis of the the sum of the squared differences or residuals SSR between the input data 18 points and the function values evaluated at the same places This quantity is often called chisquare i e the Greek letter chi to the power of 2 The algorithm attempts to minimize SSR or more precisely WSSR as the residuals are weighted by the input data errors or 1 0 before being squared see fit error_estimates for details That s why it is called least squares fitting Let s look at an example to see what is meant by non linear but first we had better go over some terms Here it is convenient to use z as the dependent variable for user defined functions of either one independent variable z f x or two independent variables z f x y A parameter is a user defined variable that fit will adjust i e an unknown quantity in the function declaration Linearity non linearity refers to the relationship of the dependent variable z to the parameters which fit is adjusting not of z to the independent variables x and or y To be technical the second and higher derivatives of the fitting function with respect to the parameters are zero for a linear least squares problem For linear least squares LLS the user defined function will be a sum of simple functions not involving any parameters each multiplied by one parameter NLLS handles more complicated functions in which parameters can be used in a
15. one can put several graphs in one figure like this default size is 5 0x3 0 inches PS 8 0 x 0 y 3 copy figa pic x 5 y 3 copy figb pic x 0 y 0 copy figc pic x 5 y 0 copy figd pic PE This will produce an 8 inch wide figure with four graphs in two rows on top of each other One can also achieve the same thing by the command set terminal gpic x y for example using PS 6 0 copy trig pic PE 34 49 25 Gpr The gpr terminal driver supports the Apollo Graphics Primitive Resource for a fixed size window It has no options If a variable window size is desired use the apollo terminal instead 34 49 26 Grass The grass terminal driver gives gnuplot capabilities to users of the GRASS geographic information system Contact grassp list moon cecer army mil for more information Pages are written to the current frame of the GRASS Graphics Window There are no options 34 49 27 Hp2623a The hp2623a terminal driver supports the Hewlett Packard HP2623A It has no options 78 34 49 28 Hp2648 The hp2648 terminal driver supports the Hewlett Packard HP2647 and HP2648 It has no options 34 49 29 Hp500c The hp500c terminal driver supports the Hewlett Packard HP DeskJet 500c It has options for resolution and compression Syntax set terminal hp500c lt res gt lt comp gt where res can be 75 100 150 or 300 dots per inch and comp can be rle or tiff Any other inputs are replaced by the defaults wh
16. or giant 9x15 pixels The size lt x y gt is given in pixels it defaults to 640x480 The number of pixels can be also modified by scaling with the set size command Each color must be of the form xrrggbb where x is the literal character x and rrggbb are the red green and blue components in hex For example x00ff00 is green The background color is set first then the border colors then the X amp Y axis colors then the plotting colors The maximum number of colors that can be set is 256 Examples set terminal gif small size 640 480 xffffff x000000 x404040 xff0000 xffa500 x66cdaa xcdb5cd xadd8e6 x0000ff xdda0dd x9500d3 defaults which uses white for the non transparent background black for borders gray for the axes and red orange medium aquamarine thistle 3 light blue blue plum and dark violet for eight plotting colors set terminal gif transparent xffffff x000000 x202020 x404040 x606060 x808080 xAOAOAO xCOCOCO xEOEOEO which uses white for the transparent background black for borders dark gray for axes and a gray scale for the six plotting colors The page size is 640x480 pixels The gif driver can create either color or monochromatic output but you have no control over which is produced The current version of the gif driver does not support animated GIFs 34 49 23 Unixplot The unixplot driver produces device independent output in the GNU plot graphics language The def
17. the value appropriate for the hardware should be selected When using 24 bit mode the colors can be directly specified via the file gnuplot_iris4d that is searched in the current directory and then in the home directory specified by the HOME environment variable This file holds RGB values for the background border labels and nine plotting colors in that order For example here is a file containing the default colors 85 85 85 Background dark gray 0 0 0 Boundary black 170 0 170 Labeling magenta 85 255 255 Plot Color 1 light cyan 170 0 0 Plot Color 2 red 0 170 0 Plot Color 3 green 255 85 255 Plot Color 4 light magenta 255 255 85 Plot Color 5 yellow 255 85 85 Plot Color 6 light red 85 255 85 Plot Color 7 light green 0 170 170 Plot Color 8 cyan 170 170 0 Plot Color 9 brown This file must have exactly 12 lines of RGB triples No empty lines are allowed and anything after the third number on a line is ignored 80 34 49 35 Kyo The kyo and prescribe terminal drivers support the Kyocera laser printer The only difference between the two is that kyo uses Helvetica whereas prescribe uses Courier There are no options 34 49 36 Latex The latex and emtex drivers allow two options Syntax set terminal latex emtex courier roman default lt fontsize gt fontsize may be any size you specify The default is for the plot to inherit its font setting from the embedding document Unless your
18. trange urange and vrange The reverse option reverses the direction of the axis e g set xrange 0 1 reverse will produce an axis with 1 on the left and 0 on the right This is identical to the axis produced by set xrange 1 0 of course reverse is intended primarily for use with autoscale The writeback option essentially saves the range found by autoscale in the buffers that would be filled by set xrange This is useful if you wish to plot several functions together but have the range determined by only some of them The writeback operation is performed during the plot execution so it must be specified before that command For example set xrange 10 10 set yrange writeback plot sin x set noautoscale y replot x 2 results in a yrange of 1 1 as found only from the range of sin x the 5 5 range of x 2 is ignored Executing show yrange after each command in the above example should help you understand what is going on In 2 d xrange and yrange determine the extent of the axes trange determines the range of the parametric variable in parametric mode or the range of the angle in polar mode Similarly in parametric 3 d xrange yrange and zrange govern the axes and urange and vrange govern the parametric variables In polar mode rrange determines the radial range plotted lt rmin gt acts as an additive constant to the radius whereas lt rmax gt acts as a clip to the radius no point with radius greater than lt rma
19. K at three quarters of whatever fontsize is currently in effect The character MUST be the first character after the If the encoding vector has been changed by set encoding the default encoding vector can be used instead by following the slash with a dash This is unnecessary if you use the Symbol font however since Symbol uses its own encoding vector gnuplot will not apply any other encoding vector to it The phantom box is useful for a b_c to align superscripts and subscripts but does not work well for overwriting an accent on a letter To do the latter it is much better to use set encoding iso_8859_1 to change to the ISO Latin 1 encoding vector which contains a large variety of letters with accents or other diacritical marks Since the box is non spacing it is sensible to put the shorter of the subscript or superscript in the box that is after the Space equal in length to a string can be inserted using the amp character Thus abc amp def ghi would produce abc ghi You can access special symbols numerically by specifying character code in octal e g Symbol 245 is the symbol for infinity You can escape control characters using e g A and so on But be aware that strings in double quotes are parsed differently than those enclosed in single quotes The major difference is that backslashes may need to be doubled when in double quoted strings Examples these are hard t
20. Laserjet Series II printer The hpdj driver supports the HP DeskJet 500 printer These drivers allow a choice of resolutions Syntax set terminal hpljii hpdj lt res gt where res may be 75 100 150 or 300 dots per inch the default is 75 Rasterization at the higher resolutions may require a large amount of memory The hp500c terminal is similar to hpdj hp500c additionally supports color and compression 79 34 49 32 Hppj The hppj terminal driver supports the HP PaintJet and HP3630 printers The only option is the choice of font Syntax set terminal hppj FNT5x9 FNT9X17 FNT13X25 with the middle sized font FNT9X17 being the default 34 49 33 Imagen The imagen terminal driver supports Imagen laser printers It is capable of placing multiple graphs on a single page Syntax set terminal imagen lt fontsize gt portrait landscape lt horiz gt lt vert gt where fontsize defaults to 12 points and the layout defaults to landscape lt horiz gt and lt vert gt are the number of graphs in the horizontal and vertical directions these default to unity Example set terminal imagen portrait 2 3 puts six graphs on the page in three rows of two in portrait orientation 34 49 34 Iris4d The iris4d terminal driver supports Silicon Graphics IRIS 4D computers Its only option is 8 or 24 bit color depth The default is 8 Syntax set terminal iris4d 8 24 The color depth is not really a choice
21. Syntax set surface set nosurface show surface The surface is drawn with the style specifed by with or else the appropriate style data or function Whenever set nosurface is issued splot will not draw points or lines corresponding to the function or data file points Contours may be still be drawn on the surface depending on the set contour option set nosurface set contour base is useful for displaying contours on the grid base See also set contour 34 49 Terminal gnuplot supports many different graphics devices Use set terminal to tell gnuplot what kind of output to generate Use set output to redirect that output to a file or device 66 Syntax set terminal lt terminal type gt show terminal If lt terminal type gt is omitted gnuplot will list the available terminal types lt terminal type gt may be abbreviated If both set terminal and set output are used together it is safest to give set terminal first because some terminals set a flag which is needed in some operating systems Several terminals have additional options For example see dumb iris4d hpljii or postscript This document may describe drivers that are not available to you because they were not installed or it may not describe all the drivers that are available to you depending on its output format 34 49 1 Aed767 The aed512 and aed767 terminal drivers support AED graphics terminals The two drivers differ only in their horizontal ranges wh
22. TeX handles the pictures as characters and uses minimal time to place them and the documents you make change more often than the pictures do It also saves a lot of TeX memory One last advantage of using the METAFONT driver is that the DVI file really remains device independent because no special commands are used as in the eepic and tpic drivers 34 49 40 Mp The mp driver produces output intended to be input to the Metapost program Running Metapost on the file creates EPS files containing the plots By default Metapost passes all text through TeX This has the advantage of allowing essentially any TeX symbols in titles and labels The mp terminal is selected with a command of the form set term mp color solid notex mag lt magsize gt lt name gt lt size gt The option color causes lines to be drawn in color on a printer or display that supports it mono chrome or nothing selects black lines The option solid draws solid lines while dashed or nothing 83 selects lines with different patterns of dashes If solid is selected but color is not nearly all lines will be identical This may occasionally be useful so it is allowed The option notex bypasses TeX entirely therefore no TeX code can be used in labels under this option This is intended for use on old plot files or files that make frequent use of common characters like and that require special handling in TeX Changing font sizes in TeX has no effect
23. a reasonable format for this unless the set format x string has supplied something that does not look like a decimal format more than one or neither f nor g See also Time date for more information 34 71 Xdtics The set xdtics commands converts the x axis tic marks to days of the week where 0 Sun and 6 Sat Overflows are converted modulo 7 to dates set noxdtics returns the labels to their default values Similar commands do the same things for the other axes Syntax set xdtics set noxdtics show xdtics The same syntax applies to ydtics zdtics x2dtics and y2dtics See also the set format command 34 72 Xlabel The set xlabel command sets the x axis label Similar commands set labels on the other axes Syntax set xlabel lt label gt lt xoff gt lt yoff gt lt font gt lt size gt show xlabel The same syntax applies to x2label ylabel y2label and zlabel Specifying the constants lt xoff gt or lt yoff gt as optional offsets for a label will move it lt xoff gt or lt yoff gt character widths or heights For example set xlabel 1 will change only the x offset of the xlabel moving the label roughly one character width to the left The size of a character depends on both the font and the terminal lt font gt is used to specify the font in which the label is written the units of the font lt size gt depend upon which terminal is used To clear a label put no options on the command line
24. an expression enclosed in parentheses or empty The expression can use 1 to access the first item read 2 for the second item and so on It can also use column x and valid x where x is an arbitrary expression resulting in an integer column x returns the x th datum valid x tests that the datum in the x th column is a valid number A column number of 0 generates a number increasing from zero with each point and is reset upon encountering two blank records A column number of 1 gives the dataline number which starts at 0 increments at single blank records and is reset at double blank records A column number of 2 gives the index number which is incremented only when two blank records are found An empty lt entry gt will default to its order in the list of entries For example using 4 is interpreted as using 1 2 4 30 N B the call command also uses s as a special character See call for details about how to include a column number in a call argument list If the using list has but a single entry that lt entry gt will be used for y and the data point number is used for x for example plot file using 1 is identical to plot file using 0 1 If the using list has two entries these will be used for x and y Additional entries are usually errors in x and or y See set style for details about plotting styles that make use of error information and fit for use of error information in curve fitting scanf
25. and pointsizes may be changed with set linestyle The postscript driver supports about 70 distinct pointtypes selectable through the pointtype option on plot and set linestyle Several possibly useful files about gnuplot s PostScript are included in the docs ps subdirectory of the gnuplot distribution and at the distribution sites These are ps_symbols gpi a gnuplot command file that when executed creates the file ps_symbols ps which shows all the symbols available through the postscript terminal ps_guide ps a PostScript file that contains a summary of the enhanced syntax and a page showing what the octal codes produce with text and symbol fonts and ps_file doc a text file that contains a discussion of the organization of a PostScript file written by gnuplot A PostScript file is editable so once gnuplot has created one you are free to modify it to your heart s desire See the editing postscript section for some hints 34 49 50 1 Enhanced postscript Enhanced Text Control Codes Control Examples Explanation a x superscript a_x subscript Q x or a b_c phantom box occupies no width amp amp space inserts space of specified length 88 Braces can be used to place multiple character text where a single character is expected e g 27 10 To change the font and or size use the full form fontname fontsize fontscale text Thus Symbol 20 G is a 20 point GAMMA and 0 75 K is a
26. are left unchanged This command is useful e g to restore the default settings at the end of a command file or to return to a defined state after lots of settings have been changed within a command file Please refer to the set command to see the default values that the various options take 33 Save The save command saves user defined functions variables set options or all three plus the last plot splot command to the specified file Syntax save lt option gt lt filename gt where lt option gt is functions variables or set If no option is used gnuplot saves functions variables set options and the last plot splot command saved files are written in text format and may be read by the load command The filename must be enclosed in quotes Examples save work gnu save functions func dat save var var dat save set options dat 34 Set show The set command can be used to sets lots of options No screen is drawn however until a plot splot or replot command is given The show command shows their settings show all shows all the settings If a variable contains time date data show will display it according to the format currently defined by set timefmt even if that was not in effect when the variable was initially defined 37 34 1 Angles By default gnuplot assumes the independent variable in polar graphs is in units of radians If set angles degrees is specified before set polar t
27. automatically so that it touches the adjacent boxes 34 47 3 Boxxyerrorbars The boxxyerrorbars style is only relevant to 2 d data plotting It is a combination of the boxes and xyerrorbars styles The box width and height are determined from the x and y errors in the same way as they are for the xyerrorbars style either from xlow to xhigh and from ylow to yhigh or from x xdelta to x xdelta and from y ydelta to y ydelta depending on how many data columns are provided 34 47 4 Candlesticks The candlesticks style is only relevant for 2 d data plotting of financial data Five columns of data are required in order these should be the x coordinate most likely a date and the opening low high and closing prices The symbol is an open rectangle centered horizontally at the x coordinate and limited vertically by the opening and closing prices A vertical line segment at the x coordinate extends up from the top of the rectangle to the high price and another down to the low The width of the rectangle may be changed by set bar The symbol will be unchanged if the low and high prices are interchanged or if the opening and closing prices are interchanged See set bar and financebars 34 47 5 Dots The dots style plots a tiny dot at each point this is useful for scatter plots with many points 34 47 6 Financebars The financebars style is only relevant for 2 d data plotting of financial data Five columns of data are required in order t
28. axes set logscale xz To enable scaling log base 2 of the y axis set logscale y 2 To disable z axis log scaling set nologscale z 34 28 Mapping If data are provided to splot in spherical or cylindrical coordinates the set mapping command should be used to instruct gnuplot how to interpret them Syntax set mapping cartesian spherical cylindrical A cartesian coordinate system is used by default For a spherical coordinate system the data occupy two or three columns or using entries The first two are interpreted as the polar and azimuthal angles theta and phi in the units specified by set angles The radius r is taken from the third column if there is one or is set to unity if there is no third column The mapping is x r cos theta cos phi y r sin theta cos phi z r sin phi Note that this is a geographic spherical system rather than a polar one For a cylindrical coordinate system the data again occupy two or three columns The first two are interpreted as theta in the units specified by set angles and z The radius is either taken from the third column or set to unity as in the spherical case The mapping is 56 x r cos theta y r sin theta zZ Z The effects of mapping can be duplicated with the using filter on the splot command but mapping may be more convenient if many data files are to be processed However even if mapping is used using may still be necessary
29. being read from a file one data point per record The letter e at the start of the first column terminates data entry The using option can be applied to these data using it to filter them through a function might make sense but selecting columns probably doesn t is intended for situations where it is useful to have data and commands together e g when gnuplot is run as a sub process of some front end application Some of the demos for example might use this feature While plot options such as index and every are recognized their use forces you to enter data that won t be used For example while plot index 0 index 1 does indeed work plot 225 44 2 4 6 e 10 12 14 e is a lot easier to type If you use with replot you may need to enter the data more than once see replot A blank filename specifies that the previous filename should be reused This can be useful with things like 29 plot a very long filename using 1 2 using 1 3 using 1 4 If you use both and on the same plot command you ll need to have two sets of inline data as in the example above On some computer systems with a popen function Unix the datafile can be piped through a shell command by starting the file name with a lt For example pop x 103x exp x 10 plot lt awk print 1 1965 2 population dat pop x would plot the same information as
30. borderGray gray50 gnuplot axisGray gray50 gnuplot linelGray gray100 gnuplot line2Gray gray60 gnuplot line3Gray gray80 gnuplot line4Gray gray40 egnuplot line5Gray gray90 gnuplot line6Gray gray50 gnuplot line7Gray gray70 gnuplot line8Gray gray30 34 49 69 5 Line_resources gnuplot honors the following resources for setting the width in pixels of plot lines shown here with their default values 0 or 1 means a minimal width line of 1 pixel width A value of 2 or 3 may improve the appearance of some plots 98 gnuplot borderWidth 2 gnuplot axisWidth 0 gnuplot linel Width gnuplot line2 Width gnuplot line3 Width gnuplot line4 Width gnuplot line5 Width gnuplot line6 Width gnuplot line7 Width gnuplot line8 Width ooococnocoo gnuplot honors the following resources for setting the dash style used for plotting lines 0 means a solid line A two digit number jk j and k are gt 1 and lt 9 means a dashed line with a repeated pattern of j pixels on followed by k pixels off For example 16 is a dotted line with one pixel on followed by six pixels off More elaborate on off patterns can be specified with a four digit value For example 4441 is four on four off four on one off The default values shown below are for monochrome displays or monochrome rendering on color or grayscale displays For color displays the default for each is 0 solid line except for axisDashes which d
31. can refer to them later by an index instead of repeating all the information at each invocation Syntax set linestyle lt index gt linetype 1t lt line_type gt linewidth lw lt line_width gt pointtype pt lt point_type gt pointsize ps lt point_size gt set nolinestyle show linestyle The line and point types are taken from the default types for the terminal currently in use The line width and point size are multipliers for the default width and size but note that lt point_size gt here is unaffected by the multiplier given on set pointsize The defaults for the line and point types is the index The defaults for the width and size are both unity Linestyles created by this mechanism do not replace the default styles both may be used Not all terminals support the linewidth and pointsize features if not supported the option will be ignored Note that this feature is not completely implemented linestyles defined by this mechanism may be used with plot splot replot and set arrow but not by other commands that allow the default index to be used such as set grid Example Suppose that the default lines for indices 1 2 and 3 are red green and blue respectively and the default point shapes for the same indices are a square a cross and a triangle respectively Then set linestyle 1 lt 2 lw 2 pt 3 ps 0 5 defines a new linestyle that is green and twice the default width an
32. command set multiplot places gnuplot in the multiplot mode in which several plots are placed on the same page window or screen Syntax 57 set multiplot set nomultiplot For some terminals no plot is displayed until the command set nomultiplot is given which causes the entire page to be drawn and then returns gnuplot to its normal single plot mode For other terminals each separate plot command produces a plot but the screen may not be cleared between plots Any labels or arrows that have been defined will be drawn for each plot according to the current size and origin unless their coordinates are defined in the screen system Just about everything else that can be set is applied to each plot too If you want something to appear only once on the page for instance a single time stamp you ll need to put a set time set notime pair around one of the plot splot or replot commands within the set multiplot set nomultiplot block The commands set origin and set size must be used to correctly position each plot see set origin and set size for details of their usage Example set size 0 7 0 7 set origin 0 1 0 set multiplot set size 0 4 0 4 set origin 0 1 0 plot sin x set size 0 2 0 2 set origin 0 5 0 5 plot cos x set nomultiplot 1 1 displays a plot of cos x stacked above a plot of sin x Note the initial set size and set origin While these are not always required their inclusion is recommended Some termina
33. ek g 48 3419 Grid ot x rte eee See ae E le aga aie A Ae oe OK 49 34 20 Hiddens dii oo AA dd e E tee ar tee MMe Merits thew Sena gh abe ae MM 49 34 21 Jsosamples 400 kee eee Be RAS nt las da a A 51 4 22 KEY n ad da de A a A AA 51 94 23 Label 2 2 it a a a ea A E ed a ADAC ss 53 34 24 Litiestyle a T Aoa A PS A DE a eS 54 34 20 Nar PIN e oa a a Wk Os b ok Bas 54 34 20 Locale cu eee ee ye A MAME RE EAL YE eee ee Ree 55 34 21 Logseales mt fio edb d Hehe eee ds EG eo bk did or glee oa RS 55 SA 238cMapping te SpA so ok ok ae eR IA id Nhe e de Same E IO 55 A DOM AT SII Sees ses tha he ee oh A A Bo A ests a a a o f Be ea oe wie o aa 56 OAS O Missing Lo to teste hw Oh a A AA lt E E ah a ge ean EAS a 56 SAS Multiplot 4 eee ee ee PAS ERE ARE Ree GR SEERA eee BOSS SH Bd 56 94 32 Mx2ties Qiu Mo oe Bele A ales eat hese Do OB RS ah aan ls 57 34 33 Mxbics AAA ee Ae Pee ee eae ee ot ee ewe ol dae as 57 94 34 My 2ties tio etn es See eee he Bk A A A 58 BAB NDICES Jade tee kt eo RR ELROD DOME A ee Se es 58 34 36 Maticsts 2 O ee a E E ee ee a aA A A N 58 IA TOS 4 Tt A Ae Me U PAG A A da Eh ee ate id 58 94 38 Origin ee Hh Ande A ch bee a Ge ee hd UR ES 58 SAS Output ee rele ye ae ae A A AA alae BE EES 59 S4 A0 ParaMetTIC y abris Be 245 44 a ale a ee a He Gs 59 IAN POSI Sar ADA a a Boh A A he AAS ds e co aa EI 60 SAA POLAR ut O dt O AAA DAA SA A A AAA a 60 IMAZ REALES de AAA A A et EE AR A 61 34 44 Rra ge 2220000242 e a a da A eed 6
34. fitting function in one graph you can display the current state of the fit Once fit has finished the update command may be used to store final values in a file for subsequent use as a parameter file See update for details 21 1 Adjustable parameters There are two ways that via can specify the parameters to be adjusted either directly on the command line or indirectly by referencing a parameter file The two use different means to set initial values Adjustable parameters can be specified by a comma separated list of variable names after the via keyword Any variable that is not already defined is is created with an initial value of 1 0 However the fit is more likely to converge rapidly if the variables have been previously declared with more appropriate starting values In a parameter file each parameter to be varied and a corresponding initial value are specified one per line in the form varname value Comments marked by and blank lines are permissible The special form varname value FIXED means that the variable is treated as a fixed parameter initialized by the parameter file but not adjusted by fit For clarity it may be useful to designate variables as fixed parameters so that their values are reported by fit The keyword FIXED has to appear in exactly this form 21 2 Beginner s guide fit is used to find a set of parameters that best fits your data to your user defined function The fit is
35. g u v z h u v Therefore a triplet of functions is required An example of a 3 d parametric function would be cos u cos v cos u sin v sin u which draws a sphere gnuplot will display an error message if all three functions are not provided for a parametric splot The total set of possible plots is a superset of the simple f x style plots since the two functions can describe the x and y values to be computed separately In fact plots of the type t f t are equivalent to 60 those produced with f x because the x values are computed using the identity function Similarly 3 d plots of the type u v f u v are equivalent to f x y Note that the order the parametric functions are specified is xfunction yfunction and zfunction and that each operates over the common parametric domain Also the set parametric function implies a new range of values Whereas the normal f x and f x y style plotting assume an xrange and yrange and zrange the parametric mode additionally specifies a trange urange and vrange These ranges may be set directly with set trange set urange and set vrange or by specifying the range on the plot or splot commands Currently the default range for these parametric variables is 5 5 Setting the ranges to something more meaningful is expected 34 41 Pointsize The set pointsize command scales the size of the points used in plots Syntax set pointsize lt multiplier gt show pointsize The default is a
36. gnuplot axisWidth 0 gnuplot linel Width gnuplot line2 Width gnuplot line3 Width gnuplot line4 Width gnuplot line5 Width gnuplot line6 Width gnuplot line7 Width gnuplot line8 Width oo0oo0ooooo0oO gnuplot honors the following resources for setting the dash style used for plotting lines 0 means a solid line A two digit number jk j and k are gt 1 and lt 9 means a dashed line with a repeated pattern of j pixels on followed by k pixels off For example 16 is a dotted line with one pixel on followed 70 by six pixels off More elaborate on off patterns can be specified with a four digit value For example 4441 is four on four off four on one off The default values shown below are for monochrome displays or monochrome rendering on color or grayscale displays For color displays the default for each is 0 solid line except for axisDashes which defaults to a 16 dotted line gnuplot borderDashes 0 gnuplot axisDashes 16 gnuplot linelDashes 0 gnuplot line2Dashes 42 gnuplot line3Dashes 13 gnuplot line4Dashes 44 gnuplot line5Dashes 15 gnuplot line6Dashes 4441 gnuplot line7Dashes 42 gnuplot line8Dashes 13 34 49 8 Cgi The cgi and hegi terminal drivers support SCO CGI drivers hegi is for printers the environment variable CGIPRNT must be set cgi may be used for either a display or hardcopy if the environment variable CGIDISP is set then that display is used
37. gt lt scale gt lt scale_z gt show view where lt rot_x gt and lt rot_z gt control the rotation angles in degrees in a virtual 3 d coordinate system aligned with the screen such that initially that is before the rotations are performed the screen hori zontal axis is x screen vertical axis is y and the axis perpendicular to the screen is z The first rotation applied is lt rot_x gt around the x axis The second rotation applied is lt rot_z gt around the new z axis 102 lt rot_x gt is bounded to the 0 180 range with a default of 60 degrees while lt rot_z gt is bounded to the 0 360 range with a default of 30 degrees lt scale gt controls the scaling of the entire splot while lt scale_z gt scales the z axis only Both scales default to 1 0 Examples set view 60 30 1 1 set view 0 5 The first sets all the four default values The second changes only scale to 0 5 See also set ticslevel 34 62 Vrange The set urange and set vrange commands set the parametric ranges used to compute x y and z values when in splot parametric mode Please see set xrange for details 34 63 X2data The set x2data command sets data on the x2 top axis to timeseries dates times Please see set xdata 34 64 X2dtics The set x2dtics command changes tics on the x2 top axis to days of the week Please see set xdtics for details 34 65 X2label The set x2label command sets the label for the x2 top axis P
38. into Bit 0 is for the horizontal edges of the grid Bit 1 for the vertical ones and Bit 2 for the diagonals that split each cell of the original grid into two triangles The default pattern is 3 making all horizontal and vertical lines visible but not the diagonals You may want to choose 7 to see those diagonals as well The undefined lt level gt option lets you decide what the algorithm is to do with data points that are undefined missing data or undefined function values or exceed the given x y or z ranges Such points can either be plotted nevertheless or taken out of the input data set All surface elements touching a point that is taken out will be taken out as well thus creating a hole in the surface If lt level gt 3 equivalent to option noundefined no points will be thrown away at all This may produce all kinds of problems elsewhere so you should avoid this lt level gt 2 will throw away undefined points but keep the out of range ones lt level gt 1 the default will get rid of out of range points as well By specifying noaltdiagonal you can override the default handling of a special case can occur if undefined is active i e lt level gt is not 3 Each cell of the grid structured input surface will be divided in two triangles along one of its diagonals Normally all these diagonals have the same orientation relative to the grid If exactly one of the four cell corners is excluded by the undefined handler an
39. is the name of a valid Windows font and lt fontsize gt is the size of the font in points Other options may be set with the graph menu the initialization file and set linestyle The Windows version normally terminates immediately as soon as the end of any files given as command line arguments is reached i e in non interactive mode It will also not show the text window at all in this mode only the plot By giving the optional argument noend or noend you can disable this behaviour 94 34 49 68 1 Graph menu The gnuplot graph window has the following options on a pop up menu accessed by pressing the right mouse button or selecting Options from the system menu Bring to Top when checked brings the graph window to the top after every plot Color when checked enables color linestyles When unchecked it forces monochrome linestyles Copy to Clipboard copies a bitmap and a Metafile picture Background sets the window background color Choose Font selects the font used in the graphics window Line Styles allows customization of the line colors and styles Print prints the graphics windows using a Windows printer driver and allows selection of the printer and scaling of the output The output produced by Print is not as good as that from gnuplot s own printer drivers Update wgnuplot ini saves the current window locations window sizes text window font text window font size graph window font graph window font size bac
40. large number of ways An example that illustrates the difference between linear and nonlinear least squares is the Fourier series One member may be written as z ax xsin c x b cos c x If a and b are the unknown parameters and c is constant then estimating values of the parameters is a linear least squares problem However if c is an unknown parameter the problem is nonlinear In the linear case parameter values can be determined by comparatively simple linear algebra in one direct step However LLS is a special case which is also solved along with more general NLLS problems by the iterative procedure that gnuplot uses fit attempts to find the minimum by doing a search Each step iteration calculates WSSR with a new set of parameter values The Marquardt Levenberg algorithm selects the parameter values for the next iteration The process continues until a preset criterium is met either 1 the fit has converged the relative change in WSSR is less than FIT_LIMIT or 2 it reaches a preset iteration count limit FIT MAXITER see fit control variables The fit may also be interrupted and subsequently halted from the keyboard see fit Often the function to be fitted will be based on a model or theory that attempts to describe or predict the behaviour of the data Then fit can be used to find values for the free parameters of the model to determine how well the data fits the model and to estimate an error range for each parameter S
41. match any data file being plotted If there are no data files autoscaling an independent variable has no effect In other words in the absence of a data file functions alone do not affect the x range or the y range if plotting z f x y Please see set xrange for additional information about ranges The behavior of autoscaling remains consistent in parametric mode see set parametric However there are more dependent variables and hence more control over x y and z axis scales In parametric 39 mode the independent or dummy variable is t for plots and u v for splots autoscale in parametric mode then controls all ranges t u v x y and z and allows x y and z to be fully autoscaled Autoscaling works the same way for polar mode as it does for parametric mode for plot with the extension that in polar mode set dummy can be used to change the independent variable from t see set dummy When tics are displayed on second axes but no plot has been specified for those axes x2range and y2range are inherited from xrange and yrange This is done before xrange and yrange are autoextended to a whole number of tics which can cause unexpected results Examples This sets autoscaling of the y axis other axes are not affected set autoscale y This sets autoscaling only for the minimum of the y axis the maximum of the y axis and the other axes are not affected set autoscale ymin This sets autoscaling of the x and y axes s
42. multiplier of 1 0 Larger pointsizes may be useful to make points more visible in bitmapped graphics The pointsize of a single plot may be changed on the plot command See plot with for details Please note that the pointsize setting is not supported by all terminal types 34 42 Polar The set polar command changes the meaning of the plot from rectangular coordinates to polar coordi nates Syntax set polar set nopolar show polar There have been changes made to polar mode in version 3 7 so that scripts for gnuplot versions 3 5 and earlier will require modification The main change is that the dummy variable t is used for the angle so that the x and y ranges can be controlled independently Other changes are 1 tics are no longer put along the zero axes automatically use set xtics axis nomirror set ytics axis nomirror 2 the grid if selected is not automatically polar use set grid polar 3 the grid is not labelled with angles use set label as necessary In polar coordinates the dummy variable t is an angle The default range of t is 0 2 pi or if degree units have been selected to 0 360 see set angles The command set nopolar changes the meaning of the plot back to the default rectangular coordinate system The set polar command is not supported for splots See the set mapping command for similar functionality for splots While in polar coordinates the meaning of an expression in t is really r f t w
43. number of character widths to be added to or subtracted from the length of the string This is useful only when you are putting a box around the key and you are using control characters in the text gnuplot simply counts the number of characters in the string when computing the box width this allows you to correct it A title can be put on the key title lt text gt see also syntax for the distinction between text in single or double quotes The key title uses the same justification as do the plot titles The defaults for set key are right top Right noreverse samplen 4 spacing 1 25 title and nobox The default lt linetype gt is the same as that used for the plot borders Entering set key with no options returns the key to its default configuration The lt position gt can be a simple x y z as in previous versions but these can be preceded by one of four keywords first second graph screen which selects the coordinate system in which the position is specified See coordinates for more details The key is drawn as a sequence of lines with one plot described on each line On the right hand side or the left hand side if reverse is selected of each line is a representation that attempts to mimic the way the curve is plotted On the other side of each line is the text description the line title obtained from the plot command The lines are vertically arranged so that an imaginary straight line divides the left and right h
44. one more window to be created This new window will be reused as long as singlewin is in effect If you switch back to multiwin generate some graphs and then switch to singlewin again the orginal singlewin window will be resused if it is still open Otherwise a new singlewin window will be created The singlewin window is not numbered 34 49 39 Mf The mf terminal driver creates a input file to the METAFONT program Thus a figure may be used in the TeX document in the same way as is a character To use a picture in a document the METAFONT program must be run with the output file from gnuplot as input Thus the user needs a basic knowledge of the font creating process and the procedure for including a new font in a document However if the METAFONT program is set up properly at the local site an unexperienced user could perform the operation without much trouble The text support is based on a METAFONT character set Currently the Computer Modern Roman font set is input but the user is in principal free to chose whatever fonts he or she needs The METAFONT source files for the chosen font must be available Each character is stored in a separate picture variable in METAFONT These variables may be manipulated rotated scaled etc when characters are needed The drawback is the interpretation time in the METAFONT program On some machines i e PC the limited amount of memory available may also cause problems if too many p
45. set to a reasonable number by default based upon the length of a decade This will be overridden if lt freq gt is given However the usual minor tics 2 3 8 9 between 1 and 10 for example are obtained by setting lt freq gt to 10 even though there are but nine sub intervals Minor tics can be used only with uniformly spaced major tics Since major tics can be placed arbitrarily by set x x2 y y2 z tics minor tics cannot be used if major tics are explicitly set By default minor tics are off for linear axes and on for logarithmic axes They inherit the settings for axis border and no mirror specified for the major tics Please see set xtics for information about these 34 34 My2tics Minor tic marks along the y2 right hand axis are controlled by set my2tics Please see set mxtics 34 35 Mytics Minor tic marks along the y axis are controlled by set mytics Please see set mxtics 34 36 Mztics Minor tic marks along the z axis are controlled by set mztics Please see set mxtics 34 37 Offsets Offsets provide a mechanism to put a boundary around the data inside of an autoscaled graph Syntax set offsets lt left gt lt right gt lt top gt lt bottom gt set nooffsets show offsets Each offset may be a constant or an expression Each defaults to 0 Left and right offsets are given in units of the x axis top and bottom offsets in units of the y axis A positive offset expands the graph in the specified directi
46. terminal These may be specified either as command line options when gnuplot is invoked or as resources in the configuration file Xdefaults They are set upon initialization and cannot be altered during a gnuplot session 34 49 69 1 Command line_options In addition to the X Toolkit options the following options may be specified on the command line when starting gnuplot or as resources in your Xdefaults file mono forces monochrome rendering on color displays gray requests grayscale rendering on grayscale or color displays Grayscale displays receive monochrome rendering by default clear requests that the window be cleared momentarily before a new plot is displayed tvtwm requests that geometry specifications for position of the window be made relative to the currently displayed portion of the virtual root raise raise plot window after each plot noraise do not raise plot window after each plot persist plot windows survive after main gnuplot program exits The options are shown above in their command line syntax When entered as resources in Xdefaults they require a different syntax Example gnuplot gray on 97 gnuplot also provides a command line option pointsize lt v gt and a resource gnuplot pointsize lt v gt to control the size of points plotted with the points plotting style The value v is a real number greater than 0 and less than or equal to ten used
47. ternary operator is very useful both in constructing piecewise functions and in plotting points only when certain conditions are met Examples Plot a function that is to equal sin x for 0 lt x lt 1 1 x for 1 lt x lt 2 and undefined elsewhere f x O lt x amp amp x lt 1 sin x 1 lt x amp amp x lt 2 1 x 1 0 plot f x Note that gnuplot quietly ignores undefined values so the final branch of the function 1 0 will produce no plottable points Note also that f x will be plotted as a continuous function across the discontinuity if a line style is used To plot it discontinuously create separate functions for the two pieces Parametric functions are also useful for this purpose For data in a file plot the average of the data in columns 2 and 3 against the datum in column 1 but only if the datum in column 4 is non negative plot file using 1 4 lt 0 1 0 2 3 2 Please see plot data file using for an explanation of the using syntax 11 10 3 User defined New user defined variables and functions of one through five variables may be declared and used any where including on the plot command itself User defined function syntax lt func name gt lt dummy1 gt lt dummy2 gt lt dummy5 gt lt expression gt where lt expression gt is defined in terms of lt dummy1 gt through lt dummy5 gt User defined variable syntax lt variable name gt lt constant expression gt
48. the default width of boxes in the boxes and boxerrorbars styles Syntax set boxwidth lt width gt show boxwidth If a data file is plotted without the width being specified in the third fourth or fifth column or using entry or if a function is plotted the width of each box is set by the set boxwidth command If a width is given both in the file and by the set boxwidth command the one in the file is used If the width is not specified in one of these ways the width of each box will be calculated automatically so that it touches the adjacent boxes In a four column data set the fourth column will be interpreted as the box width unless the width is set to 2 0 in which case the width will be calculated automatically See set style boxerrorbars for more details To set the box width to automatic use the command set boxwidth or for four column data set boxwidth 2 The same effect can be achieved with the using keyword in plot plot file using 1 2 3 4 2 34 8 Clabel gnuplot will vary the linetype used for each contour level when clabel is set When this option on the default a legend labels each linestyle with the z level it represents It is not possible at present to separate the contour labels from the surface key Syntax set clabel lt format gt set noclabel show clabel The default for the format string is 8 3g which gives three decimal places This may produce poor label alignment if the k
49. the first population example but with years since 1965 as the x axis If you want to execute this example you have to delete all comments from the data file above or substitute the following command for the first part of the command above the part up to the comma plot lt awk 0 print 1 1965 2 population dat While this approach is most flexible it is possible to achieve simple filtering with the using or thru keywords 26 1 6 Thru The thru function is provided for backward compatibility Syntax plot file thru f x It is equivalent to plot file using 1 f 2 While the latter appears more complex it is much more flexible The more natural plot file thru f y also works i e you can use y as the dummy variable thru is parsed for splot and fit but has no effect 26 1 7 Using The most common datafile modifier is using Syntax plot file using lt entry gt lt entry gt lt entry gt format If a format is specified each datafile record is read using the C library s scanf function with the specified format string Otherwise the record is read and broken into columns at spaces or tabs A format cannot be specified if time format data is being used this must be done by set data time The resulting array of data is then sorted into columns according to the entries Each lt entry gt may be a simple column number which selects the datum
50. the z axis to days of the week Please see set xdtics for details 34 93 Zero The zero value is the default threshold for values approaching 0 0 Syntax set zero lt expression gt show zero gnuplot will not plot a point if its imaginary part is greater in magnitude than the zero threshold This threshold is also used in various other parts of gnuplot as a crude numerical error threshold The default zero value is le 8 zero values larger than le 3 the reciprocal of the number of pixels in a typical bitmap display should probably be avoided but it is not unreasonable to set zero to 0 0 34 94 Zeroaxis The x axis may be drawn by set xzeroaxis and removed by set noxzeroaxis Similar commands behave similarly for the y x2 and y2 axes Syntax set x x2lyly2 zeroaxis linestyle ls lt line_style gt linetype 1t lt line_type gt linewidth lw lt line_width gt set no x x2lyly2 zeroaxis show xly zeroaxis By default these options are off The selected zero axis is drawn with a line of type lt line_type gt and width lt line_width gt if supported by the terminal driver currently in use or a user defined style lt line_style gt If no linetype is specified any zero axes selected will be drawn using the axis linetype linetype 0 set zeroaxis is equivalent to set xzeroaxis l set yzeroaxis l set nozeroaxis is equivalent to set noxzeroaxis set noyzeroaxis 34 95 Zlabel This command sets th
51. to 1 2 with user defined style 5 use set arrow to 1 2 ls 5 To set an arrow from bottom left of plotting area to 5 5 3 and tag the arrow number 3 use set arrow 3 from graph 0 0 to 5 5 3 To change the preceding arrow to end at 1 1 1 without an arrow head and double its width use set arrow 3 to 1 1 1 nohead lw 2 To draw a vertical line from the bottom to the top of the graph at x 3 use set arrow from 3 graph 0 to 3 graph 1 nohead To delete arrow number 2 use set noarrow 2 To delete all arrows use set noarrow To show all arrows in tag order use show arrow 34 3 Autoscale Autoscaling may be set individually on the x y or z axis or globally on all axes The default is to autoscale all axes Syntax set autoscale lt axes gt min max set noautoscale lt axes gt min max show autoscale where lt axes gt is either x y z x2 y2 or xy A keyword with min or max appended this cannot be done with xy tells gnuplot to autoscale just the minimum or maximum of that axis If no keyword is given all axes are autoscaled When autoscaling the axis range is automatically computed and the dependent axis y for a plot and z for splot is scaled to include the range of the function or data being plotted If autoscaling of the dependent axis y or z is not set the current y or z range is used Autoscaling the independent variables x for plot and x y for splot is a request to set the domain to
52. with set dummy The optional lt min gt and lt max gt terms can be constant expressions or In non parametric mode the order in which ranges must be given is xrange and yrange In parametric mode the order for the plot command is trange xrange and yrange The following plot command shows setting the trange to pi pi the xrange to 1 3 1 3 and the yrange to 1 1 for the duration of the graph plot pi pi 1 3 1 3 1 1 sin t t 2 Note that the x2range and y2range cannot be specified here set x2range and set y2range must be used Ranges are interpreted in the order listed above for the appropriate mode Once all those needed are specified no further ones must be listed but unneeded ones cannot be skipped use an empty range as a placeholder can be used to allow autoscaling of either of min and max See also set autoscale Ranges specified on the plot or splot command line affect only that graph use the set xrange set yrange etc commands to change the default ranges for future graphs With time data you must provide the range in the same manner as the time appears in the datafile within quotes gnuplot uses the timefmt string to read the value see set timefmt Examples This uses the current ranges plot cos x This sets the x range only plot 10 30 sin pixx pi x This is the same but uses t as the dummy variable plot t 10 30 sin pi t pi t This sets both the x and y r
53. x xdelta y to x xdelta y depending on how many data columns are provided A tic mark is placed at the ends of the error bar unless set bar is used see set bar for details 34 47 16 Xyerrorbars The xyerrorbars style is only relevant to 2 d data plots xyerrorbars is like dots except that horizontal and vertical error bars are also drawn At each point x y lines are drawn from x y ydelta to x y ydelta and from x xdelta y to x xdelta y or from x ylow to x yhigh and from xlow y to xhigh y depending upon the number of data columns provided A tic mark is placed at the ends of the error bar unless set bar is used see set bar for details If data are provided in an unsupported mixed form the using filter on the plot command should be used to set up the appropriate form For example if the data are of the form x y xdelta ylow yhigh then you can use plot data using 1 2 1 3 1 3 4 5 with xyerrorbars 34 47 17 Yerrorbars The yerrorbars or errorbars style is only relevant to 2 d data plots yerrorbars is like dots except that a vertical error bar is also drawn At each point x y a line is drawn from x y ydelta to x y ydelta or from x ylow to x yhigh depending on how many data columns are provided A tic mark is placed at the ends of the error bar unless set bar is used see set bar for details 34 48 Surface The command set surface controls the display of surfaces by splot
54. xdata time is given also Syntax set timefmt lt format string gt show timefmt 100 The string argument tells gnuplot how to read timedata from the datafile The valid formats are Time Series timedata Format Specifiers Format Explanation ha day of the month 1 31 m month of the year 1 12 hy year 0 99 YY year 4 digit hj day of the year 1 365 4H hour 0 24 7M minute 0 60 S second 0 60 hb three character abbreviation of the name of the month B name of the month Any character is allowed in the string but must match exactly t tab is recognized Backslash octals nnn are converted to char If there is no separating character between the time date elements then d m y WH M and S read two digits each Y reads four digits and j reads three digits b requires three characters and B requires as many as it needs Spaces are treated slightly differently A space in the string stands for zero or more whitespace characters in the file That is H M can be used to read 1220 and 12 20 as well as 12 20 Each set of non blank characters in the timedata counts as one column in the using n n specification Thus 11 11 25 12 76 21 0 consists of three columns To avoid confusion gnuplot requires that you provide a complete using specification if your file contains timedata Since gnuplot cannot read non numerical text if the date format includes the day or month in words the format st
55. y ylow yhigh x y xdelta x y xlow xhigh or x y xlow xhigh ylow yhigh In all cases the numbers on each record of a data file must be separated by white space one or more blanks or tabs unless a format specifier is provided by the using option This white space divides each record into columns Data may be written in exponential format with the exponent preceded by the letter e E d D q or Q Only one column the y value need be provided If x is omitted gnuplot provides integer values starting at 0 In datafiles blank records records with no characters other than blanks and a newline and or carriage return are significant pairs of blank records separate indexes see plot datafile index Data separated by double blank records are treated as if they were in separate data files Single blank records designate discontinuities in a plot no line will join points separated by a blank records if they are plotted with a line style If autoscaling has been enabled set autoscale the axes are automatically extended to include all datapoints with a whole number of tic marks if tics are being drawn This has two consequences i For splot the corner of the surface may not coincide with the corner of the base In this case no vertical line is drawn ii When plotting data with the same x range on a dual axis graph the x coordinates may not coincide if the x2tics are not being drawn This is because the x axis has been autoexten
56. 0 2 5 In mixed expressions integers are promoted to reals before evaluation 5 2e0 2 5 The result of division of a negative integer by a positive one may vary among compilers Try a test like print 5 2 to determine if your system chooses 2 or 3 as the answer The integer expression 1 0 may be used to generate an undefined flag which causes a point to ignored the ternary operator gives an example The real and imaginary parts of complex expressions are always real whatever the form in which they are entered in 3 2 the 3 and 2 are reals not integers 10 1 Functions The functions in gnuplot are the same as the corresponding functions in the Unix math library except that all functions accept integer real and complex arguments unless otherwise noted For those functions that accept or return angles that may be given in either degrees or radians sin x cos x tan x asin x acos x atan x atan2 x and arg z the unit may be selected by set angles which defaults to radians Math library functions Function Arguments Returns abs x any absolute value of x x same type abs x complex length of z real x imag zx acos x any cos x inverse cosine acosh x any cosh inverse hyperbolic cosine in radians arg x complex the phase of x asin x any sin g inverse sin asinh x any sinh x inverse hyperbolic sin in radians atan x any tan x inverse tangent a
57. 1 S4A5 Samples e a e A e A dE Oe ESS MEE 61 SLAG SIZES ohn A A A A ee A EA ete EA A O 61 SATSE rt eee A bean AA A ta e da do da AS 62 34 471 Boxerrorbars iure a a a te a 63 34 41 27 BOXES ma A EE Ae e ee a AR 63 SALAS BOKXYEETOLDALS is a a o 2 Pop e e A as ae a ae A 63 SAAT A Candlesticks 3 5 a h Aad aire e ok Oe eid da eh eo BR aS 63 IAS DOS fee Pa ata MEME RRA SS A Ee eee ee ees 63 3447 6 Kinancebars 44 4544 4448 ee4 a sek a oe bade 63 SLA ESTEPA aa eee Sect ete ee ee e Bo a ed 64 GAAS FIStepss oa ob ded tease ald hod ks Re ahh a ee ER a a A wth ed 64 IVATO Impulse nata da SE eee ls A AAA Sa ee 64 S44 10 ines II A A LD e AA A 64 34 41 11 Linespoiits 4 ea w meee e a de LAA ER 64 SEAT Points ake a e A e Pee ee eee AAA 64 SAAT IS SLEDS dy A A A eA ad E A da o do 64 34 41 14 VeCtOR ecc ae a a a a a Ro a a aa 65 JAJA 1D Kerrorbars a a a a e a a 65 34 A16 Xyetrorbars a A A a A 65 SAAC T Verror bats 4k A A Bg e ae 65 GAAS SUTLACE e eek bbb kD Bede de dee eee SE gee ade a bh ears a dd Be aS 65 34 49 Terminal er terere ye a Re a ee Ree Es 65 BAAQ a1 ACTION 3 4 a4 42444448 8 Pee a See oo he 66 BASAQD AM aa a eh AY EA da Ahh Es eae SS 66 SAA Amigaa dl Set A Ae A AAA a e 66 SAAJA Apollo fed ee NE Ahk A AAA tine Me ENE Mich te Gi A a 66 34 49 5 Atari ST via AES o ee 67 34 49 6 Atari ST via VDD s qosirin ei d e ea a aaae e a a R 67 34 A907 BE e ee o E A ta eRe A 67 34 49 7 1 Command line options
58. 2 Beginner spidere ni dra A A A aid a dodo a 21 31 Error EStIMALES ce veo a cta MAR RR AA eee ee De 21 3 1 Statistical overview s ate ie rres g arae 22220 A 21 3 2 Practical guidelin s ermita a e ee ad ca a a 214 Pat controling ti au ce A A A Ph ce Re a e a Das E A ANS 214 1 Gontrol variables di A e A AAA A AA 21 4 2 Environment variables xau acta o a ap ea ala A o A 21 0 Moulticbranchy 2 s m e u e de e de de a ee eee a eee a RAS Ge 21 6 Startin Valles dera A ee Od ae a ee A Delis APS a si A Hehehe eis rias ado AOS D aei of 6 PROSA 22 Help 23 If 24 Load 25 Pause 26 Plot 26 11 Dat stile qt pta a e A A di ath tthe at des ol a T de AO TS A NO 26 12 Example datafile a miva a tt e A a aa e A Aa 20 31 ndek e ei amp a ote tas Roe do aio oa Sea aes 20 14 Smooth ioe A A SE Wee DAS A td KOSH A 26 1 4 1 Acsplines 4 2405 04 44 ls doa beh neste bo RRS Sate 206 1 4 2 Bezier 244 0 eee eee ee hs 24 F meee ee Rees S 26 1 4 3 Csplines 3 4 she Seo SSS aaa le Be oe AERIS RSs ZO LAA spbezier IL A A E AS 26 1 4 5 Un iqU a 2 cs ante ee Ge ee et E E E ee el es ei ce eS 26 105 Special flenames 2 2 t 4 4 4 o ae ea ee ee eS 20 110 Lira das Wb de be edad A e BAO Sete ge beh Gd Sars 26 0 USING cea ne 2 A a a ES 2612 Error bars 2 svete Sa ele En ait ye eee lee A aan a ote AS 20 3 Rara mettia tt a lar ee A ke e A de bee Ai eth Gio gh ah eR D 15 16 16 16 17 17 18 19 19 20 20 21 21 21 22 23 23
59. 60 dpi printers Only nec cp6 has any options Syntax set terminal nec cp6 monochrome colour draft which defaults to monochrome With each of these drivers a binary copy is required on a PC to print Do not use print use instead copy file b lpt1 34 49 19 Excl The excl terminal driver supports Talaris printers such as the EXCL Laser printer and the 1590 It has no options 34 49 20 Hercules These drivers supports PC monitors with autodetected graphics boards They can be used only when compiled with Zortech C C None have options 34 49 21 Fig The fig terminal device generates output in the Fig graphics language Syntax set terminal fig monochrome color small big pointsmax lt max_points gt landscape portrait metric inches fontsize lt fsize gt size lt xsize gt lt ysize gt thickness lt units gt depth lt layer gt 75 monochrome and color determine whether the picture is black and white or color small and big produce a 5x3 or 8x5 inch graph in the default landscape mode and 3x5 or 5x8 inches in portrait mode lt max_points gt sets the maximum number of points per polyline Default units for editing with xfig may be metric or inches fontsize sets the size of the text font to lt fsize gt points size sets overrides the size of the drawing area to lt xsize gt lt ysize gt in units of inches or centimeters depending on the inches or metric setting in effect depth
60. Also a history mechanism allows previous commands to be edited and re executed After the command line has been edited a newline or carriage return will enter the entire line without regard to where the cursor is positioned The readline function in gnuplot is not the same as the readline used in GNU Bash and GNU Emacs If the GNU version is desired it may be selected instead of the gnuplot version at compile time The editing commands are as follows Command line Editing Commands Character Function Line Editing B move back a single character E move forward a single character A move to the beginning of the line E move to the end of the line H DEL delete the previous character D delete the current character K delete from current position to the end of line L R redraw line in case it gets trashed U delete the entire line W delete from the current word to the end of line History P move back through history N move forward through history On the IBM PC the use of a TSR program such as DOSEDIT or CED may be desired for line editing The default makefile assumes that this is the case by default gnuplot will be compiled with no line editing capability If you want to use gnuplot s line editing set READLINE in the makefile and add readline obj to the link file The following arrow keys may be used on the IBM PC and Atari versions if readline is used Arrow key
61. Function Left same as B Right same as F Ctrl Left same as A Ctrl Right same as E P N Up same as Down same as The Atari version of readline defines some additional key aliases 7 Comments Comments are supported as follows a may appear in most places in a line and gnuplot will ignore the rest of the line It will not have this effect inside quotes inside numbers including complex numbers inside command substitutions etc In short it works anywhere it makes sense to work 8 Coordinates The commands set arrow set key and set label allow you to draw something at an arbitrary position Arrow key Function Undo same as L Home same as A Ctrl Home same as E Esc same as U Help help plus return Ctrl Help help on the graph This position is specified by the syntax lt system gt lt x gt lt system gt lt y gt lt system gt lt z gt Each lt system gt can either be first second graph or screen first places the x y or z coordinate in the system defined by the left and bottom axes second places it in the system defined by the second axes top and right graph specifies the area within the axes 0 0 is bottom left and 1 1 is top right for splot 0 0 0 is bottom left of plotting area use negative z to get to the base see set ticslevel and screen specifies the screen area the entire area not just the portion selected by set size
62. Otherwise CGIPRNT is used These terminals have no options 34 49 9 Cgm The cgm terminal generates a Computer Graphics Metafile This file format is a subset of the ANSI X3 122 1986 standard entitled Computer Graphics Metafile for the Storage and Transfer of Picture Description Information Several options may be set in cgm Syntax set terminal cgm lt mode gt lt color gt lt rotation gt solid dashed width lt plot_width gt linewidth lt line_width gt lt font gt lt fontsize gt where lt mode gt is landscape portrait or default lt color gt is either color or monochrome lt rotation gt is either rotate or norotate solid draws all curves with solid lines overriding any dashed patterns lt plot_width gt is the width of the page in points lt line_width gt is the line width in points lt font gt is the name of a font and lt fontsize gt is the size of the font in points By default cgm uses rotated text for the Y axis label The first six options can be in any order Selecting default sets all options to their default values Examples set terminal cgm landscape color rotate dashed width 432 linewidth 1 Arial Bold 12 defaults set terminal cgm 14 linewidth 2 14 wider lines amp larger font set terminal cgm portrait Times Roman Italic 12 set terminal cgm color solid no pesky dashes 34 49 9 1 Font The first part of a Computer Graphics Metafile the metafile descripti
63. S a ee ee E A ee a de a Bok E Sb Goat al at a 102 IAS KITES ok Qo ne hh eo a Bl AS Se ee ee 102 94 69 X2ZET OOS i Ow ee a a ne a Se a E E eee ga 102 SANO KATA e A RO OO BARS S S BG ays DE eee 103 DAL RATICS Gs Sk hk bh bBo de de eae aE argo a Wk Ot erga bok a 103 34 12 Kabel inate cee eye ye eed AAA E EEA A ee Rees 103 SAMS XMS e Me eh eb nae eed ee eed EE ee AA eee a od Rae 104 IA TARTA i ty SA Se ok ke ae RR da AE he a Ds e os Same OS Bd 104 SALO ALIES La he ee oh ead A As Bo de cd ea atte E e ef Be ea A Ate 105 SA LOX ZCTOOIAS tor Corde Me AE oo Be oh ce i LA th He SE ME Neal 6k Gh r a AS A 107 SASTRE ERO EER SEERA eee A SS Bs 107 DASS Y 2AE Me oe Bee A ales eat hee DEAR RS SE 107 SAO AD label amp 4 cco ee we eg A eae ee ote me ee lew el dae da 107 94 80 Y 2mtics e 4M ee ete ws fee eee he Bk A AS 107 94 31 Y DEMO aa ot ee o DOME A ee Ses 108 AN o O ee ee ee ee 108 34 83 VLZOTOAR S lt i tacita Ae Ae Ye hak AS ee GR Ge ae de O a a a epee a 108 94 84 Vidata yrs amp tahna da ded Meebo Geb bee a Ge deh Re A ar 108 SAISON AMES ce a A A A A ae Be ES 108 94 86 Vlabel wing BiG bd bd rra a ee pala be eu ak Behera oe ole Wom dls 108 OAS AMICS a ty ie Ach te a e a En e de AA e le ao at eh Bd 108 ILSE TAE a O dt ADA LAA A a ate al AA AA ten 108 GABON GIES AM do A LALA A A tE eo IS 108 RU A a ee aa EEE ewe eee eee ORO e S 108 34 01 7datanwin 4 eke AR RA SREESE EASE Ae eee Cee OE Eee BES 108 A s p 2 aa we ve Ye ek A a ee ee Ge ae eyes
64. a fails but cd c newdata works as expected 18 Call The call command is identical to the load command with one exception you can have up to ten additional parameters to the command delimited according to the standard parser rules which can be substituted into the lines read from the file As each line is read from the called input file it is scanned for the sequence dollar sign followed by a digit 0 9 Tf found the sequence is replaced by the corresponding parameter from the call command line If the parameter was specified as a string in the call line it is substituted without its enclosing quotes followed by any character other than a digit will be that character E g use to get a single Providing more than ten parameters on the call command line will cause an error A parameter that was not provided substitutes as nothing Files being called may themselves contain call or load commands The call command must be the last command on a multi command line Syntax call lt input file gt lt parameter 0 gt lt parm 1 gt lt parm 9 gt The name of the input file must be enclosed in quotes and it is recommended that parameters are similarly enclosed in quotes future versions of gnuplot may treat quoted and unquoted arguments differently Example If the file calltest gp contains the line print p0 0 p1 1 p2 2 p3 3 p4 4 p5 5 p6 6 p7 x 7x entering the command call calltest gp
65. age return is hit pause 3 Wait three seconds pause 1 Hit return to continue pause 10 Isn t this pretty It s a cubic spline 26 Plot plot is the primary command for drawing plots with gnuplot It creates plots of functions and data in many many ways plot is used to draw 2 d functions and data splot draws 2 d projections of 3 d surfaces and data plot and splot contain many common features see splot for differences Note specifically that splot s binary and matrix options do not exist for plot Syntax plot lt ranges gt lt function gt lt datafile gt datafile modifiers axes lt axes gt lt title spec gt with lt style gt definitions lt function gt where either a lt function gt or the name of a data file enclosed in quotes is supplied A function is a mathematical expression or a pair of mathematical expressions in parametric mode The expressions may be defined completely or in part earlier in the stream of gnuplot commands see user defined It is also possible to define functions and parameters on the plot command itself This is done merely by isolating them from other items with commas There are four possible sets of axes available the keyword lt axes gt is used to select the axes for which a particular line should be scaled x1y1 refers to the axes on the bottom and left x2y2 to those on the top and right xly2 to those on the bottom and right and x2y1 to those on the top a
66. al linewidth Z grid lines are drawn on the back of the plot This looks better if a partial box is drawn around the plot see set border 34 20 Hidden3d The set hidden3d command enables hidden line removal for surface plotting see splot Some optional features of the underlying algorithm can also be controlled using this command Syntax set hidden3d defaults f offset lt offset gt mooffset trianglepattern lt bitpattern gt undefined lt level gt noundefined no altdiagonal no bentover set nohidden3d show hidden3d In contrast to the usual display in gnuplot hidden line removal actually treats the given function or data grids as real surfaces that can t be seen through so parts behind the surface will be hidden by it 50 For this to be possible the surface needs to have grid structure see splot datafile about this and it has to be drawn with lines or with linespoints When hidden3d is set both the hidden portion of the surface and possibly its contours drawn on the base see set contour as well as the grid will be hidden Each surface has its hidden parts removed with respect to itself and to other surfaces if more than one surface is plotted Contours drawn on the surface set contour surface don t work Labels and arrows are always visible and are unaffected The key is also never hidden by the surface Functions are evaluated at isoline intersections The algorithm interpol
67. all variants of a circle and thus will only repeat after 12 curves are plotted with points The PostScript drivers postscript supplies a total of 64 If you wish to choose the line or point type for a single plot lt line_type gt and lt point_type gt may be specified These are positive integer constants or expressions that specify the line type and point type to be used for the plot Use test to display the types available for your terminal You may also scale the line width and point size for a plot by using lt line width gt and lt point_size gt which are specified relative to the default values for each terminal The pointsize may also be altered globally see set pointsize for details But note that both lt point_size gt as set here and as set by set 34 pointsize multiply the default point size their effects are not cumulative That is set pointsize 2 plot x w p ps 3 will use points three times default size not six If you have defined specific line type width and point type size combinations with set linestyle one of these may be selected by setting lt line_style gt to the index of the desired style The keywords may be abbreviated as indicated Note that the linewidth and pointsize options are not supported by all terminals Examples This plots sin x with impulses plot sin x with impulses This plots x with points x 2 with the default plot x y w points x 2 yx x 2 This plots tan x with th
68. ame as above set terminal cgm width 10 2 54 72 10 cm wide 72 34 49 9 8 Winword6 The default font table was chosen to match where possible the default font assignments made by the Computer Graphics Metafile input filter for Microsoft Word 6 0c although the filter makes available only Arial and Times Roman fonts and their bold and or italic variants Other fonts such as Helvetica and Roman are not available If the CGM file includes a font table the filter mostly ignores it However it changes certain font assignments so that they disagree with the table As a workaround the winword6 option deletes the font table from the CGM file In this case the filter makes predictable font assignments Arial Bold is correctly assigned even with the font table present which is one reason it was chosen as the default winword6 disables the color tables for a similar reason with the color table included Microsoft Word displays black for color 7 Linewidths and pointsizes may be changed with set linestyle 34 49 10 Corel The corel terminal driver supports CorelDraw Syntax set terminal corel default monochrome color lt fontname gt lt fontsize gt lt xsize gt lt ysize gt lt linewidth gt where the fontsize and linewidth are specified in points and the sizes in inches The defaults are mono chrome SwitzerlandLight 22 8 2 10 and 1 2 34 49 11 Debug This terminal is provided t
69. and set cntrparam and set dgrid3d re 3 d data When a 2 d graph is being done only the value of lt samples_1 gt is relevant When a surface plot is being done without the removal of hidden lines the value of samples specifies the number of samples that are to be evaluated for the isolines Each iso v line will have lt sample_1 gt samples and each iso u line will have lt sample_2 gt samples If you only specify lt samples_1 gt lt samples_2 gt will be set to the same value as lt samples_1 gt See also set isosamples 34 46 Size The set size command scales the displayed size of the plot Syntax set size no square ratio lt r gt noratio lt xscale gt lt yscale gt show size The lt xscale gt and lt yscale gt values are the scaling factors for the size of the plot which includes the graph and the margins ratio causes gnuplot to try to create a graph with an aspect ratio of lt r gt the ratio of the y axis length to the x axis length within the portion of the plot specified by lt xscale gt and lt yscale gt The meaning of a negative value for lt r gt is different If lt r gt 1 gnuplot tries to set the scales so that the unit has the same length on both the x and y axes suitable for geographical data for instance If lt r gt 2 the unit on y has twice the length of the unit on x and so on 62 The success of gnuplot in producing the requested aspect ratio depends on the terminal selected The
70. and sides of the key It is the coordinates of the top of this line that are specified with the set key command In a plot only the x and y coordinates are used to specify the line position For a splot x y and z are all used as a 3 d location mapped using the same mapping as the graph itself to form the required 2 d screen position of the imaginary line Some or all of the key may be outside of the graph boundary although this may interfere with other labels and may cause an error on some devices If you use the keywords outside or below gnuplot makes space for the keys and the graph becomes smaller Putting keys outside to the right they occupy as few columns as possible and putting them below as many columns as possible depending of the length of the labels thus stealing as little space from the graph as possible When using the TeX or PostScript drivers or similar drivers where formatting information is embedded in the string gnuplot is unable to calculate correctly the width of the string for key positioning If the key is to be positioned at the left it may be convenient to use the combination set key left Left reverse The box and gap in the grid will be the width of the literal string If splot is being used to draw contours the contour labels will be listed in the key If the alignment of these labels is poor or a different number of decimal places is desired the label format can be specified See set clabel for details Exa
71. anges plot pi pi 3 3 tan x 1 x This sets only the y range and turns off autoscaling on both axes plot 2 sin 5 8 sin x besj0 x This sets xmax and ymin only plot 200 pi exp sin x This sets the x range for a timeseries set timefmt d m y H 7M plot 1 6 93 12 00 5 6 93 12 00 timedata dat 26 5 Title A line title for each function and data set appears in the key accompanied by a sample of the line and or symbol used to represent it It can be changed by using the title option Syntax 33 title lt title gt notitle where lt title gt is the new title of the line and must be enclosed in quotes The quotes will not be shown in the key A special character may be given as a backslash followed by its octal value 1345 The tab character t is understood Note that backslash processing occurs only for strings enclosed in double quotes use single quotes to prevent such processing The newline character n is not processed in key entries in either type of string The line title and sample can be omitted from the key by using the keyword notitle A null title title gt gt is equivalent to notitle If only the sample is wanted use one or more blanks title By default the line title is the function or file name as it appears on the plot command If it is a file name any datafile modifiers specified will be included in the default title The layout of the key itsel
72. are used together it is safest to give set terminal first because some terminals set a flag which is needed in some operating systems This would be the case for example if the operating system needs to know whether or not a file is to be formatted in order to open it properly On machines with popen functions Unix output can be piped through a shell command if the first non whitespace character of the filename is For instance set output lpr Plaser filename set output lp dlaser filename On MSDOS machines set output PRN will direct the output to the default printer On VMS output can be sent directly to any spooled device It is also possible to send the output to DECnet transparent tasks which allows some flexibility 34 40 Parametric The set parametric command changes the meaning of plot splot from normal functions to para metric functions The command set noparametric restores the plotting style to normal single valued expression plotting Syntax set parametric set noparametric show parametric For 2 d plotting a parametric function is determined by a pair of parametric functions operating on a parameter An example of a 2 d parametric function would be plot sin t cos t which draws a circle if the aspect ratio is set correctly see set size gnuplot will display an error message if both functions are not provided for a parametric plot For 3 d plotting the surface is described as x f u v y
73. argins and any text written therein A plot contains one graph A graph is defined by an abscissa and an ordinate although these need not actually appear on it A graph may contain one or more lines A line is a single function or data set Line is also a plotting style The word will also be used in sense a line of text Presumably the context will remove any ambiguity The lines on a graph may have individual names These may be listed together with a sample of the plotting style used to represent them in the key sometimes also called the legend The word title occurs with multiple meanings in gnuplot In this document it will always be preceded by the adjective plot line or key to differentiate among them 12 A graph may have up to four labelled axes Various commands have the name of an axis built into their names such as set xlabel Other commands have one or more axis names as options such as set logscale xy The names of the four axes for these usages are x for the axis along the bottom border of the plot y for the left border x2 for the top border and y2 for the right border z also occurs in commands used with 3 d plotting When discussing data files the term record will be resurrected and used to denote a single line of text in the file that is the characters between newline or end of record characters A point is the datum extracted from a single record A datablock is a set of points f
74. ary data is 112 int fwrite_matrix file m nrl nrl ncl nch row_title column_title An example of using these routines is provided in the file bf test c which generates binary files for the demo file demo binary dem The index keyword is not supported since the file format allows only one surface per file The every and using filters are supported using operates as if the data were read in the above triplet form 36 1 2 Example datafile A simple example of plotting a 3 d data file is splot datafile dat where the file datafile dat might contain The valley of the Gnu 00 10 O 1 10 0 2 10 1 0 10 115 1 2 10 2 0 10 211 2 2 10 3 0 10 310 3 2 10 ja Note that datafile dat defines a 4 by 3 grid 4 rows of 3 points each Rows datablocks are separated by blank records Note also that the x value is held constant within each dataline If you instead keep y constant and plot with hidden line removal enabled you will find that the surface is drawn inside out Actually for grid data it is not necessary to keep the x values constant within a datablock nor is it necessary to keep the same sequence of y values gnuplot requires only that the number of points be the same for each datablock However since the surface mesh from which contours are derived connects sequentially corresponding points the effect of an irregular grid on a surface plot is unpredictable and should be examined on a case by case b
75. as a scaling factor for point sizes For example pointsize 2 uses points twice the default size and pointsize 0 5 uses points half the normal size 34 49 69 2 Monochome options For monochrome displays gnuplot does not honor foreground or background colors The default is black on white rv or gnuplot reverseVideo on requests white on black 34 49 69 3 Color_resources For color displays gnuplot honors the following resources shown here with their default values or the greyscale resources The values may be color names as listed in the X11 rgb txt file on your system hexadecimal RGB color specifications see X11 documentation or a color name followed by a comma and an intensity value from 0 to 1 For example blue 0 5 means a half intensity blue gnuplot background white gnuplot textColor black gnuplot borderColor black gnuplot axisColor black gnuplot line1Color red gnuplot line2Color green gnuplot line3Color blue gnuplot line4Color magenta gnuplot line5Color cyan gnuplot line6Color sienna gnuplot line7Color orange gnuplot line8Color coral The command line syntax for these is for example Example gnuplot background coral 34 49 69 4 Grayscale_resources When gray is selected gnuplot honors the following resources for grayscale or color displays shown here with their default values Note that the default background is black gnuplot background black gnuplot textGray white gnuplot
76. asis 36 1 3 Matrix The matrix flag indicates that the ASCII data are stored in matrix format The z values are read in a row at a time i e zii z12 z13 z14 z21 z22 z23 z24 z31 z32 z33 z34 and so forth The row and column indices are used for the x and y values 113 36 2 Grid data The 3D routines are designed for points in a grid format with one sample datapoint at each mesh intersection the datapoints may originate from either evaluating a function see set isosamples or reading a datafile see splot datafile The term isoline is applied to the mesh lines for both functions and data Note that the mesh need not be rectangular in x and y as it may be parameterized in u and v see set isosamples However gnuplot does not require that format In the case of functions samples need not be equal to isosamples i e not every x isoline sample need intersect a y isoline In the case of data files if there are an equal number of scattered data points in each datablock then isolines will connect the points in a datablock and cross isolines will connect the corresponding points in each datablock to generate a surface In either case contour and hidden3d modes may give different plots than if the points were in the intended format Scattered data can be converted to a different grid format with set dgrid3d The contour code tests for z intensity along a line between a point on a y isoline and the co
77. ata sets can be simultaneously fit with functions of one indepen dent variable having common parameters by minimizing the total WSSR The function and parameters branch for each data set are selected by using a pseudo variable e g either the dataline number a column index of 1 or the datafile index 2 as the second independent variable Example Given two exponential decays of the form z f x each describing a different data set but having a common decay time estimate the values of the parameters If the datafile has the format x z s then f x y y 0 a exp x tau brexp x tau fit f x y datafile using 1 1 2 3 via a b tau For a more complicated example see the file hexa fnc used by the fit dem demo Appropriate weighting may be required since unit weights may cause one branch to predominate if there is a difference in the scale of the dependent variable Fitting each branch separately using the multi branch solution as initial values may give an indication as to the relative effect of each branch on the joint solution 21 6 Starting values Nonlinear fitting is not guaranteed to converge to the global optimum the solution with the smallest sum of squared residuals SSR and can get stuck at a local minimum The routine has no way to determine that it is up to you to judge whether this has happened fit may and often will get lost if started far from a solution where SSR is large and changi
78. ated by pstex can be included in any plain based format including LaTeX Syntax set terminal pslatex pstex lt color gt lt dashed gt lt rotate gt f auxfile lt font_size gt 89 lt color gt is either color or monochrome lt rotate gt is either rotate or norotate and determines if the y axis label is rotated lt font_size gt is used to scale the font from its usual size If auxfile is specified it directs the driver to put the PostScript commands into an auxiliary file instead of directly into the LaTeX file This is useful if your pictures are large enough that dvips cannot handle them The name of the auxiliary PostScript file is derived from the name of the TeX file given on the set output command it is determined by replacing the trailing tex actually just the final extent in the file name with ps in the output file name or if the TeX file has no extension ps is appended Remember to close the file before leaving gnuplot All drivers for LaTeX offer a special way of controlling text positioning If any text string begins with you also need to include a at the end of the text and the whole text will be centered both horizontally and vertically by LaTeX If the text string begins with you need to continue it with a position specification up to two out of t b l r f the text itself and finally The text itself may be anything LaTeX can typeset as an LR box rule
79. ated expression can be used The crucial point is that the expression is evaluated once if it doesn t start with a left parenthesis or once for each data point read if it does If timeseries data are being used the time can span multiple columns The starting column should be specified Note that the spaces within the time must be included when calculating starting columns for other data E g if the first element on a line is a time with an embedded space the y value should be specified as column three It should be noted that plot file plot file using 1 2 and plot file using 1 2 can be subtly different 1 if file has some lines with one column and some with two the first will invent x values when they are missing the second will quietly ignore the lines with one column and the third will store an undefined value for lines with one point so that in a plot with lines no line joins points across the bad point 2 if a line contains text at the first column the first will abort the plot on an error but the second and third should quietly skip the garbage In fact it is often possible to plot a file with lots of lines of garbage at the top simply by specifying plot file using 1 2 However if you want to leave text in your data files it is safer to put the comment character in the first column of the text lines 31 26 2 Errorbars Error bars are supported for 2 d data file plots by reading one to fo
80. ates linearly between function points or data points when determining the visible line segments This means that the appearance of a function may be different when plotted with hidden3d than when plotted with nohidden3d because in the latter case functions are evaluated at each sample Please see set samples and set isosamples for discussion of the difference The algorithm used to remove the hidden parts of the surfaces has some additional features controllable by this command Specifying defaults will set them all to their default settings as detailed below If defaults is not given only explicitly specified options will be influenced all others will keep their previous values so you can turn on off hidden line removal via set no hidden3d without modifying the set of options you chose The first option offset influences the linestyle used for lines on the back side Normally they are drawn in a linestyle one index number higher than the one used for the front to make the two sides of the surface distinguishable You can specify a different line style offset to add instead of the default 1 by offset lt offset gt Option nooffset stands for offset 0 making the two sides of the surface use the same linestyle Next comes the option trianglepattern lt bitpattern gt lt bitpattern gt must be a number between 0 and 7 interpreted as a bit pattern Each bit determines the visibility of one edge of the triangles each surface is split up
81. ault size of the PostScript results generated by plot2ps is 5 x 3 inches this can be increased up to about 8 25 x 8 25 by set size Syntax set terminal unixplot lt fontname gt lt fontsize gt which defaults to 10 point Courier There is a non GNU version of the unixplot driver which cannot be compiled unless this version is left out 34 49 24 Gpic The gpic terminal driver generates GPIC graphs in the Free Software Foundations s groff package The default size is 5 x 3 inches The only option is the origin which defaults to 0 0 Syntax set terminal gpic lt x gt lt y gt where x and y are in inches A simple graph can be formatted using 77 groff p mpic Tps file pic gt file ps The output from pic can be pipe lined into eqn so it is possible to put complex functions in a graph with the set label and set x y label commands For instance set ylab space O int from 0 to x alpha t roman d tQ will label the y axis with a nice integral if formatted with the command gpic filename pic geqn d Tps groff m macro package Tps gt filename ps Figures made this way can be scaled to fit into a document The pic language is easy to understand so the graphs can be edited by hand if need be All co ordinates in the pic file produced by gnuplot are given as x gnuplotx and y gnuploty By default x and y are given the value 0 If this line is removed with an editor in a number of files
82. ays receive monochrome rendering by default clear requests that the window be cleared momentarily before a new plot is displayed tvtwm requests that geometry specifications for position of the window be made relative to the currently displayed portion of the virtual root raise raise plot window after each plot noraise do not raise plot window after each plot persist plot windows survive after main gnuplot program exits The options are shown above in their command line syntax When entered as resources in Xdefaults they require a different syntax Example gnuplot gray on gnuplot also provides a command line option pointsize lt v gt and a resource gnuplot pointsize lt v gt to control the size of points plotted with the points plotting style The value v is a real number greater than 0 and less than or equal to ten used as a scaling factor for point sizes For example pointsize 2 uses points twice the default size and pointsize 0 5 uses points half the normal size 34 49 7 2 Monochome options For monochrome displays gnuplot does not honor foreground or background colors The default is black on white rv or gnuplot reverseVideo on requests white on black 34 49 7 3 Color resources For color displays gnuplot honors the following resources shown here with their default values or the greyscale resources The values may be color names as listed in the BE rgb txt file on you
83. bel LaTeX gamma at 0 0 Specify own positioning top here set xlabel t LaTeX gamma 7 The other label account for long ticlabels set ylabel r LaTeX gamma rule 7mm Opt 34 49 37 Linux The linux driver has no additional options to specify It looks at the environment variable GSVG AMODE for the default mode if not set it uses 1024x768x256 as default mode or if that is not possible 640x480x16 standard VGA 34 49 38 Macintosh Several options may be set in the macintosh driver Syntax 81 set terminal macintosh singlewin multiwin vertical novertical size lt width gt lt height gt default singlewin limits the output to a single window and is useful for animations multiwin allows multiple windows vertical is only valid under the gx option With this option rotated text be drawn vertically novertical turns this option off size lt width gt lt height gt overrides the graph size set in the preferences dialog until it is cleared with either set term mac size default or set term mac default set term mac size default sets the window size settings to those set in the preferences dialog gt set term mac default sets all options to their default values Default values nogx multiwin novertical If you generate graphs under the multiwin option and then switch to singlewin the next plot command will cause
84. between single and double quotes 34 56 Tmargin The command set tmargin sets the size of the top margin Please see set margin for details 34 57 Trange The set trange command sets the parametric range used to compute x and y values when in parametric or polar modes Please see set xrange for details 34 58 Urange The set urange and set vrange commands set the parametric ranges used to compute x y and z values when in splot parametric mode Please see set xrange for details 34 59 Variables The show variables command lists all user defined variables and their values Syntax show variables 34 60 Version The show version command lists the version of gnuplot being run its last modification date the copyright holders and email addresses for the FAQ the info gnuplot mailing list and reporting bugs in short the information listed on the screen when the program is invoked interactively Syntax show version long When the long option is given it also lists the operating system the compilation options used when gnuplot was installed the location of the help file and again the useful email addresses 34 61 View The set view command sets the viewing angle for splots It controls how the 3 d coordinates of the plot are mapped into the 2 d screen space It provides controls for both rotation and scaling of the plotted data but supports orthographic projections only Syntax set view lt rot_x gt lt rot_z
85. bility with older versions the following forms are also permitted set clip set noclip set clip is synonymous with set clip points set noclip turns off all three types of clipping 34 10 Cntrparam set cntrparam controls the generation of contours and their smoothness for a contour plot show contour displays current settings of cntrparam as well as contour Syntax set cntrparam linear cubicspline bspline points lt n gt order lt n gt 1 levels auto lt n gt lt n gt discrete lt z1 gt lt z2 gt lt z3 gt incremental lt start gt lt incr gt lt end gt show contour This command has two functions First it sets the values of z for which contour points are to be determined by linear interpolation between data points or function isosamples Second it controls the way contours are drawn between the points determined to be of equal z lt n gt should be an integral constant expression and lt zl gt lt z2 gt any constant expressions The parameters are linear cubicspline bspline Controls type of approximation or interpolation If linear then straight line segments connect points of equal z magnitude If cubicspline then piecewise linear con tours are interpolated between the same equal z points to form somewhat smoother contours but which 43 may undulate If bspline a guaranteed smoother curve is drawn which only approximates the position of the points of equal z poin
86. centering both horizontally and vertically set label LaTeX gamma at 0 0 Specify own positioning top here set xlabel t LaTeX gamma The other label account for long ticlabels set ylabel r LaTeX gamma rule 7mm Opt 34 49 17 Emxvga The emxvga emxvesa and vgal terminal drivers support PCs with SVGA vesa SVGA and VGA graphics boards respectively They are intended to be compiled with emx gcc under either DOS or OS 2 They also need VESA and SVGAKIT maintained by Johannes Martin JMARTIN GOOFY ZDV UNI MAINZ DE with additions by David J Liu liu phri nyu edu Syntax 74 set terminal emxvga set terminal emxvesa vesa mode set terminal vgal The only option is the vesa mode for emxvesa which defaults to G640x480x256 34 49 18 Epson 180dpi This driver supports a family of Epson printers and derivatives epson 180dpi and epson 60dpi are drivers for Epson LQ style 24 pin printers with resolutions of 180 and 60 dots per inch respectively epson 1x800 is a generic 9 pin driver appropriate for printers like the Epson LX 800 the Star NL 10 and NX 1000 the PROPRINTER and so forth nec cp6 is generix 24 pin driver that can be used for printers like the NEC CP6 and the Epson LQ 800 The okidata driver supports the 9 pin OKIDATA 320 321 Standard printers The starc driver is for the Star Color Printer The tandy 60dpi driver is for the Tandy DMP 130 series of 9 pin
87. current logscale s mantissa to base of current logscale scientific power YT power to base 10 AL power to base of current logscale AS scientific power he character replacement for scientific power YP multiple of pi 47 A scientific power is one such that the exponent is a multiple of three Character replacement of scientific powers c has been implemented for powers in the range 18 to 18 For numbers outside of this range the format reverts to exponential Other acceptable modifiers which come after the but before the format specifier are which left justifies the number which forces all numbers to be explicitly signed which places a decimal point after floats that have only zeroes following the decimal point a positive integer which defines the field width 0 the digit not the letter immediately preceding the field width which indicates that leading zeroes are to be used instead of leading blanks and a decimal point followed by a non negative integer which defines the precision the minimum number of digits of an integer or the number of digits following the decimal point of a float Some releases of printf may not support all of these modifiers but may also support others in case of doubt check the appropriate documentation and then experiment Examples set format y t set ytics 5 10 5 0 and 1 0 set format y 4s set ytics 500 1000 500 and 1 0 set format y 12 3
88. d a new pointstyle that is a half sized triangle The commands set function style lines plot f x 1t 3 g x 1s 1 will create a plot of f x using the default blue line and a plot of g x using the user defined wide green line Similarly the commands set function style linespoints plot p x lt 1 pt 3 q x 1s 1 will create a plot of f x using the default triangles connected by a red line and q x using small triangles connected by a green line 34 25 Lmargin The command set Imargin sets the size of the left margin Please see set margin for details 55 34 26 Locale The locale setting determines the language with which x y z d m tics will write the days and months Syntax set locale lt locale gt lt locale gt may be any language designation acceptable to your installation See your system documen tation for the available options The default value is determined from the LANG environment variable 34 27 Logscale Log scaling may be set on the x y z x2 and or y2 axes Syntax set logscale lt axes gt lt base gt set nologscale lt axes gt show logscale where lt axes gt may be any combinations of x y and z in any order or x2 or y2 and where lt base gt is the base of the log scaling If lt base gt is not given then 10 is assumed If lt axes gt is not given then all axes are assumed set nologscale turns off log scaling for the specified axes Examples To enable log scaling in both x and z
89. d as a constant expression see plot datafile using e g using 1 2 3 1 Multiple datasets may be simultaneously fit with functions of one independent variable by making y a pseudo variable e g the dataline number and fitting as two independent variables See fit multi branch The via qualifier specifies which parameters are to be adjusted either directly or by referencing a parameter file Examples f x a x 2 b x c g x y a x 2 b y 2 c x y FIT_LIMIT 1e 6 fit f x measured dat via start par fit f x measured dat using 3 7 5 via start par fit f x data trash dat using 1 2 3 via a b c fit g x y surface dat using 1 2 3 1 via a b c After each iteration step detailed information about the current state of the fit is written to the display The same information about the initial and final states is written to a log file fit log This file is always appended to so as to not lose any previous fit history it should be deleted or renamed as desired The fit may be interrupted by pressing Ctrl C any key but Ctrl C under MSDOS and Atari Multitasking Systems After the current iteration completes you have the option to 1 stop the fit and accept the current parameter values 2 continue the fit 3 execute a gnuplot command as specified by the environment variable FIT SCRIPT The default for FIT SCRIPT is replot so if you had previously plotted both the data and the
90. d this is on the usual diagonal both triangles will be excluded However if the default setting of altdiagonal is active the other diagonal will be chosen for this cell instead minimizing the size of the hole in the surface The bentover option controls what happens to another special case this time in conjunction with the trianglepattern For rather crumply surfaces it can happen that the two triangles a surface cell is divided into are seen from opposite sides i e the original quadrangle is bent over as illustrated in the following ASCII art C B original quadrangle A B displayed quadrangle IN set view 0 0 YA set view 75 75 perhaps 17 C D NI 51 A D If the diagonal edges of the surface cells aren t generally made visible by bit 2 of the lt bitpattern gt there the edge CB above wouldn t be drawn at all normally making the resulting display hard to understand Therefore the default option of bentover will turn it visible in this case If you don t want that you may choose nobentover instead 34 21 Isosamples The isoline density grid for plotting functions as surfaces may be changed by the set isosamples command Syntax set isosamples lt iso_1 gt lt iso_2 gt show isosamples Each function surface plot will have lt iso_1 gt iso u lines and lt iso_2 gt iso v lines If you only specify lt iso_1 gt lt iso_2 gt will be set to the same value as lt iso_1 gt By d
91. d unless set bar is used see set bar for details If autoscaling is on the ranges will be adjusted to include the error bars See plot using plot with and set style for more information 26 3 Parametric When in parametric mode set parametric mathematical expressions must be given in pairs for plot and in triplets for splot Examples plot sin t t 2 splot cos u cos v cos u sin v sin u Data files are plotted as before except any preceding parametric function must be fully specified before a data file is given as a plot In other words the x parametric function sin t above and the y parametric function t 2 above must not be interrupted with any modifiers or data functions doing so will generate a syntax error stating that the parametric function is not fully specified Other modifiers such as with and title may be specified only after the parametric function has been completed plot sin t t 2 title Parametric example with linespoints 26 4 Ranges The optional ranges specify the region of the graph that will be displayed Syntax 32 lt dummy var gt lt min gt lt max gt lt min gt lt max gt The first form applies to the independent variable xrange or trange if in parametric mode The sec ond form applies to the dependent variable yrange and xrange too if in parametric mode lt dummy var gt is a new name for the independent variable The defaults may be changed
92. data style shows the current default data plotting style 34 13 Degrid3d The set dgrid3d command enables and can set parameters for non grid to grid data mapping Syntax set dgrid3d lt row_size gt lt col_size gt lt norm gt set nodgrid3d show dgrid3d By default dgrid3d is disabled When enabled 3 d data read from a file are always treated as a scattered data set A grid with dimensions derived from a bounding box of the scattered data and size as specified by the row col_size parameters is created for plotting and contouring The grid is equally spaced in x 45 rows and in y columns the z values are computed as weighted averages of the scattered points z values The third parameter norm controls the weighting Each data point is weighted inversely by its distance from the grid point raised to the norm power Actually the weights are given by the inverse of dx norm dy norm where dx and dy are the components of the separation of the grid point from each data point For some norms that are powers of two specifically 4 8 and 16 the computation is optimized by using the Euclidean distance in the weight calculation dx 2 dx 2 norm 2 However any non negative integer can be used The closer the data point is to a grid point the more effect it has on that grid point and the larger the value of norm the less effect more distant data points have on that grid point The dgrid3d option is a simple low pass
93. ded to a whole number of tics but the x2 axis has not The following example illustrates the problem reset plot 11 19 19 e 11 19 19 e 26 26 1 1 Every The every keyword allows a periodic sampling of a data set to be plotted In the discussion a point is a datum defined by a single record in the file block here will mean the same thing as datablock see glossary Syntax plot file every lt point_incr gt lt block_incr gt lt start_point gt lt start_block gt lt end_point gt lt end_block gt The data points to be plotted are selected according to a loop from lt start_point gt to lt end_point gt with increment lt point_incr gt and the blocks according to a loop from lt start_block gt to lt end_block gt with increment lt block_incr gt The first datum in each block is numbered 0 as is the first block in the file Note that records containing unplottable information are counted Any of the numbers can be omitted the increments default to unity the start values to the first point or block and the end values to the last point or block If every is not specified all points in all lines are plotted Examples every 3 3 selects just the fourth block 0 is first every 9 selects the first 10 blocks every 2 2 selects every other point in every other block selects points 5 through 15 in each block 26 1 2 Example data
94. dow which remains open when gnuplot exits This option takes an optional numerical argument which specifies an instance of the server process Thus multiple server windows can be in use at the same time If widelines is specified all plots will be drawn with wide lines If enhanced is specified sub and superscripts and multiple fonts are enabled using the same syntax as the enhanced postscript option see set terminal postscript enhanced for details Font names for the basic PostScript fonts may be abbreviated to single letters If title is specified it will be used as the title of the plot window It will also be used as the name of the server instance and will override the optional numerical argument Linewidths may be changed with set linestyle 34 49 49 Png The png terminal driver supports Portable Network Graphics To compile it you will need the third party libraries libpng and zlib both are available at ftp ftp uu net graphics png png has two options Syntax set terminal png small medium large monochrome gray color The defaults are small fontsize and monochrome Default size of the output is 640 480 pixel 87 34 49 50 Postscript Several options may be set in the postscript driver Syntax set terminal postscript lt mode gt enhanced noenhanced color monochrome solid dashed lt duplexing gt lt fontname gt lt fontsize gt where lt mode gt is landscape portrait e
95. driver is capable of building fonts at any size e g dvips stick to the standard 10 11 and 12 point sizes METAFONT users beware METAFONT does not like odd sizes All drivers for LaTeX offer a special way of controlling text positioning If any text string begins with you also need to include a at the end of the text and the whole text will be centered both horizontally and vertically If the text string begins with you need to follow this with a position specification up to two out of t b Lr J the text itself and finally The text itself may be anything LaTeX can typeset as an LR box rule s may help for best positioning Points among other things are drawn using the LaTeX commands Diamond and Box These commands no longer belong to the LaTeX2e core they are included in the latexsym package which is part of the base distribution and thus part of any LaTeX implementation Please do not forget to use this package Points are drawn with the LaTex commands Diamond and Box These commands do no longer belong to the LaTeX2e core but are included in the latexsym package in the base distribution and are hence part of all LaTeX implementations Please do not forget to use this package Examples About label positioning Use gnuplot defaults mostly sensible but sometimes not really best set title LaTeX gamma Force centering both horizontally and vertically set la
96. e When in polar mode set polar the xrange and the yrange are both found from the polar coordinates and thus they can both be automatically scaled In other words in polar mode both the x and y axes can be automatically scaled to fit the ranges of the polar function that is being plotted When plotting functions in polar mode the rrange may be autoscaled When plotting data files in polar mode the trange may also be autoscaled Note that if the trange is contained within one quadrant autoscaling will produce a polar plot of only that single quadrant Explicitly setting one or two ranges but not others may lead to unexpected results 40 34 4 Bar The set bar command controls the tics at the ends of errorbars Syntax set bar small large lt size gt show bar small is a synonym for 0 0 and large for 1 0 The default is 1 0 if no size is given 34 5 Bmargin The command set bmargin sets the size of the bottom margin Please see set margin for details 34 6 Border The set border and set noborder commands control the display of the graph borders for the plot and splot commands Syntax set border lt integer gt linestyle ls lt line_style gt linetype 1t lt line_type gt linewidth lw lt line_width gt set noborder show border The borders are encoded in a 12 bit integer the bottom four bits control the border for plot and the sides of the base for splot The next four bits control the ver
97. e enclosed in quotes on the splot command line Syntax 111 splot lt file_name gt binary matrix index lt index list gt every lt every list gt using lt using list gt The special filenames and are permitted as in plot In brief binary and matrix indicate that the the data are in a special form index selects which data sets in a multi data set file are to be plotted every specifies which datalines subsets within a single data set are to be plotted and using determines how the columns within a single record are to be interpreted The options index and every behave the same way as with plot using does so also except that the using list must provide three entries instead of two The plot options thru and smooth are not available for splot but cntrparams and dgrid3d provide limited smoothing cabilities Data file organization is essentially the same as for plot except that each point is an x y z triple If only a single value is provided it will be used for z the datablock number will be used for y and the index of the data point in the datablock will be used for x If two values are provided gnuplot gives you an error message Three values are interpreted as an x y z triple Additional values are generally used as errors which can be used by fit Single blank records separate datablocks in a splot datafile splot treats datablocks as the equivalent of function y isolines No line will join
98. e Ge 94 34 49 68 4 Wenuplot ini s o o pn aa a a e ee 95 34 49 68 5 Windows3 0 e aE ANANA E E E ee 95 34ANG RTI o Dia he OO AA a aa aaa an Bh OL aS ate a a a amp 96 34 49 69 1 Command line options 0 000002 ee eee 96 34 49 69 2 Monochome options oaoa e 97 34 49 69 3 Color resources ee 97 34 49 69 4 Grayscale_resources 0 osoa a 97 3449 69 5 LIne TESQUECES 0 a ee ee A a 97 SAAD TO AMD da ES o A AA E A A a 98 A E hah A en ae dhe oe E Oe ee ied 98 4 51 Vicslevel ost os REESE AR eee ee Dh CO ee SE ESS MGS 98 34 52 escalera ve ve ve Yeh A a a eee Gi sar hg tp ee te ee ata hah te S 99 94 53 Timestamp 6 ond be ee bb ethane ees aan ee ta a ge ee deters 99 SADA MEA 3 aol ne eh eRe ee a AAA 99 94 50 Witle 8 a wasn ee od eee a ES EE Ae Ge ee eR as 100 ALO GE IN a i A e Ye She US Sty hh SO aR GD So Sp Sy ne alo Sh Odsal dh 101 DAT range o a Ge de Sede dee aig ee ey le ds 101 34 58 Urange eg cee ee A AAA AA ee Bee ES 101 34 09 Varlables ue artritis dde ra eb eee hh ede eee baile 101 34 60 Version amp 234M ok oe ee A BO Bake Ae SY Bd 101 ALOU NASW a ta ld ti A he DAA A A LAS A A ali 101 SAOZ MIRLOS Lu teta a a Se eee andie E AA Se A 102 AI ee eee ee eh a PARE EER RS PER ASE PRA ee ARBRE BA es 102 SA OA XI AMES e Me ee Ae ee eee eee beet ee SSSA aE 102 SA Oo MMA bel s amp 2 eek he ee eee ee ee Rhee bee dP me ee See eee eae ae 102 34 66 A PPO DLE BA Bont Maa ee ee Oe eB od 102 DATA LIADBE
99. e are reported for the final WSSR If the data are unweighted stdfit is the rms value of the deviation of the data from the fitted function in user units If you supplied valid data errors the number of data points is large enough and the model is correct the reduced chisquare should be about unity For details look up the chi squared distribution in your favourite statistics reference If so there are additional tests beyond the scope of this overview for determining how well the model fits the data A reduced chisquare much larger than 1 0 may be due to incorrect data error estimates data errors not normally distributed systematic measurement errors outliers or an incorrect model function A plot of the residuals e g plot datafile using 1 2 f 1 may help to show any systematic trends Plotting both the data points and the function may help to suggest another model Similarly a reduced chisquare less than 1 0 indicates WSSR is less than that expected for a random sample from the function with normally distributed errors The data error estimates may be too large the statistical assumptions may not be justified or the model function may be too general fitting fluctuations in a particular sample in addition to the underlying trends In the latter case a simpler function may be more appropriate You ll have to get used to both fit and the kind of problems you apply it to before you can relate the standard
100. e default function style file data 1 with lines plot 2 5 tan x data 1 with 1 This plots leastsq dat with impulses plot leastsq dat w i This plots the data file population with boxes plot population with boxes This plots exper dat with errorbars and lines connecting the points errorbars require three or four columns plot exper dat w lines exper dat notitle w errorbars This plots sin x and cos x with linespoints using the same line type but different point types plot sin x with linesp 1t 1 pt 3 cos x with linesp 1t 1 pt 4 This plots file data with points of type 3 and twice usual size plot data with points pointtype 3 pointsize 2 This plots two data sets with lines differing only by weight plot di t good w 1 1t 2 lw 3 d2 t bad w 1 1t 2 1w 1 See set style to change the default styles 27 Print The print command prints the value of lt expression gt to the screen It is synonymous with pause 0 lt expression gt may be anything that gnuplot can evaluate that produces a number or it can be a string Syntax print lt expression gt lt expression gt See expressions 28 Pwd The pwd command prints the name of the working directory to the screen 35 29 Quit The exit and quit commands and END OF FILE character will exit gnuplot Each of these commands will clear the output device as does the clear command before e
101. e handled correctly However the text may not appear if you send the Metapost output as is to a PostScript interpreter 34 49 40 1 Metapost Instructions Set your terminal to Metapost e g set terminal mp mono cmtt12 12 Select an output file e g set output figure mp Create your pictures Each plot or multiplot group will generate a separate Metapost beginfig endfig group Its default size will be 5 by 3 inches You can change the size by saying set size 0 5 0 5 or whatever fraction of the default size you want to have 84 Quit gnuplot Generate EPS files by running Metapost on the output of gnuplot mpost figure mp OR mp figure mp The name of the Metapost program depends on the system typically mpost for a Unix machine and mp on many others Metapost will generate one EPS file for each picture To include your pictures in your document you can use the graphics package in LaTeX or epsf tex in plain TeX usepackage graphics LaTeX input epsf tex plainTeX If you use a driver other than dvips for converting TeX DVI output to PS you may need to add the following line in your LaTeX document DeclareGraphicsRule eps Each picture you made is in a separate file The first picture is in e g figure 0 the second in figure 1 and so on To place the third picture in your document for example all you have to do is includegraphics figure 2 LaTeX epsfbox figure 2 plainTeX The ad
102. e label for the z axis Please see set xlabel 34 96 Zmtics The set zmtics command changes tics on the z axis to months of the year Please see set xmtics for details 34 97 Zrange The set zrange command sets the range that will be displayed on the z axis The zrange is used only by splot and is ignored by plot Please see set xrange for details 110 34 98 Ztics The set ztics command controls major labelled tics on the z axis Please see set xtics for details 35 Shell The shell command spawns an interactive shell To return to gnuplot type logout if using VMS exit or the END OF FILE character if using Unix endcli if using AmigaOS or exit if using MS DOS or OS 2 A single shell command may be spawned by preceding it with the character if using VMS at the beginning of a command line Control will return immediately to gnuplot after this command is executed For example in Unix AmigaOS MS DOS or OS 2 dir prints a directory listing and then returns to gnuplot On an Atari the command first checks whether a shell is already loaded and uses it if available This is practical if gnuplot is run from gulam for example 36 Splot splot is the command for drawing 3 d plots well actually projections on a 2 d surface but you knew that It can create a plot from functions or a data file in a manner very similar to the plot command See plot for features common to the plot command only differences are discuss
103. ear week starts on Monday y year 0 99 LY year 4 digit Except for the non numerical formats these may be preceded by a 0 zero not oh to pad the field length with leading zeroes and a positive digit to define the minimum field width which will be overridden if the specified width is not large enough to contain the number There is a 24 character limit to the length of the printed text longer strings will be truncated Examples Suppose the text is 76 12 25 23 11 11 Then set format x defaults to 12 25 76 n 23 11 set format x ZA d b ZY Saturday 25 Dec 1976 set format x r fd 11 11 11 pm 12 25 76 Suppose the text is 98 07 06 05 04 03 Then set format x 1y 2m 3d 01H 02M 03S 98 7 6 5 04 003 34 17 Function style The set function style command changes the default plotting style for function plots Syntax set function style lt style choice gt show function style See set style for the choices If no choice is given the choices are listed show function style shows the current default function plotting style 34 18 Functions The show functions command lists all user defined functions and their definitions Syntax 49 show functions For information about the definition and usage of functions in gnuplot please see expressions 34 19 Grid The set grid command allows grid lines to be drawn on the plot Syntax set grid no m xtics no m ytics n
104. ed LaTeX picture environment It is an alternative to the latex driver The output of this terminal is intended for use with the eepic sty macro package for LaTeX To use it you need eepic sty epic sty and a printer driver that supports the tpic specials If your printer driver doesn t support those specials eepicemu sty will enable you to use some of them Although dotted and dashed lines are possible with eepic and are tempting they do not work well for high sample rate curves fusing the dashes all together into a solid line For now the eepic driver creates only solid lines There is another gnuplot driver tpic that supports dashed lines but it cannot be used if your DVI driver doesn t support tpic specials All drivers for LaTeX offer a special way of controlling text positioning If any text string begins with you also need to include a at the end of the text and the whole text will be centered both horizontally and vertically by LaTeX If the text string begins with you need to continue it with a position specification up to two out of t b l r f the text itself and finally The text itself may be anything LaTeX can typeset as an LR box rule s may help for best positioning The eepic terminal has no options Examples About label positioning Use gnuplot defaults mostly sensible but sometimes not really best set title LaTeX gamma Force
105. ed in detail here Note specifically that the binary and matrix options discussed under datafile modifiers are not available for plot Syntax splot lt ranges gt lt function gt lt datafile gt datafile modifiers lt title spec gt with lt style gt definitions lt function gt where either a lt function gt or the name of a data file enclosed in quotes is supplied The function can be a mathematical expression or a triple of mathematical expressions in parametric mode By default splot draws the xy plane completely below the plotted data The offset between the lowest ztic and the xy plane can be changed by set ticslevel The orientation of a splot projection is controlled by set view See set view and set ticslevel for more information The syntax for setting ranges on the splot command is the same as for plot In non parametric mode the order in which ranges must be given is xrange yrange and zrange In parametric mode the order is urange vrange xrange yrange and zrange The title option is the same as in plot The operation of with is also the same as in plot except that the plotting styles available to splot are limited to lines points linespoints dots and impulses the error bar capabilities of plot are not available for splot The datafile options have more differences 36 1 Data file As for plot discrete data contained in a file can be displayed by specifying the name of the data fil
106. ede dae Boke eas ii dd dE S aa 75 34 49 23 Unizplob v c se A a en EO A A 76 3449 24 GpiG ve A A ES ea E ed at aG 76 JA ADO DARA A A a e is 77 34 49 20 Grass Haro o a h e e A amp bb ds ad 77 3449 27 AP20230e a E E a AAA 77 34 49 28 Hp2048 00502 646 HD ae 444 8 Pee e aaa ed Rae 78 31 49 29 Hp900 aaa dd A ede Mes he o Seatac PE IO 78 GLAD BO pel ld AA A aise ht aie a A aa Se Ste eat 78 IAN LST A pit ye di AA a E iat the E dh a 78 34 49 32 Appl cri SAY CREAN ERE REC a eee BESS SHE 79 34 49 33 Imagen de eee hee hoe ee SE BB ae wats 79 344934 slds eo ee eye ee ee Ot ee ee eo pew eda a as 79 34 49 35 KYO 2 4 ele Bee e beet he Bk A 23a 8 A 80 34 49 30 Latex ow RRO a A ie a 80 O A a ES ee ee ee Ge ee ee 80 34 49 38 Macintosh a u 2a A BOO BADER Oe Be Be ee ade Skee ds 80 34 A939 Mis a a bbb a See Pe ek Re Ge deh Rt RE Be 81 34 49 39 1 METAFONT Instructions oaa 81 SLAG AQMP arras 6 He eee eee ed Bde be Geek a Hake Woe hes 82 34 49 40 1 Metapost Instructions 2 e 83 SAAD AL Mor 2 5 8 od duct oe Gace ake A A a a a a te A Sick aba aay 84 SAJ A2 MIES oie bs Bk he he A A BOR ME A A Ge cee a AS A 84 34 49 43 Mtos Aca oe ae eee SS coed Adee eee AROS ee ed 85 SAA 4A Next ae ekRR e SE SA eee eet he Cee OE OSS ww aR 85 34 49 45 Next econ E Be ek eee Gre ee te eye wie ee at A heh at es 85 34 49 46 Phiten nag PP ee bbb ba eee Gis aah 44 OO Ge ee EDS 85 SAAJAT DOSPE fot es ho Re a a ee le is 86 34 49 48 Pi
107. ee fit error_estimates Alternatively in curve fitting functions are selected independent of a model on the basis of experience as to which are likely to describe the trend of the data with the desired resolution and a minimum number of parameters functions The fit solution then provides an analytic representation of the curve However if all you really want is a smooth curve through your data points the smooth option to plot may be what you ve been looking for rather than fit 21 3 Error estimates In fit the term error is used in two different contexts data error estimates and parameter error estimates Data error estimates are used to calculate the relative weight of each data point when determining the weighted sum of squared residuals WSSR or chisquare They can affect the parameter estimates since they determine how much influence the deviation of each data point from the fitted function has on the final values Some of the fit output information including the parameter error estimates is more meaningful if accurate data error estimates have been provided The statistical overview describes some of the fit output and gives some background for the practical guidelines 19 21 3 1 Statistical overview The theory of non linear least squares NLLS is generally described in terms of a normal distribution of errors that is the input data is assumed to be a sample from a population having a given mean and a Gau
108. eee et att haba da 109 94 93 ZElO do ee ee BP PELE hm eee bah et E fd SLSR 109 DADA LOT OARS 50 ah seven ete th ee he a a de do Te Ee ay a LAA 109 34 95 Alaber x ami sis Soka oe RAE EES EE RAO E oe a es 109 SAIO LME A oe YE ERMA POLES de waa Bb Cada ee ee S 109 DAIOTATANGE Se hk dd bb by ee eet a woh Oh Sr Siar da a da 109 349S ES a A AAA A AA AAA 110 35 Shell 110 36 Splot 110 36 1 Watashle 400 Bae eh Ae nl La lead de o RA 110 30h BID A 2d wee eo he ed 111 36 1 2 Example datafile our ee OR we ee EAA a 112 S023 gt Matrixis oY ae Bhs o Seas Behe Saw Yipes 112 30 2 Grid datars od id Se gan RA a hh or RS HSS ORAIG LLY 113 30 3 SplotsovervieW bh ceci a A a da de of oa ead 113 37 Test 113 38 Update 114 III Graphical User Interfaces 114 IV Bugs 114 39 Old_bugs 115 gnuplot 3 7 1 Part I Gnuplot 1 Copyright Copyright C 1986 1993 1998 Thomas Williams Colin Kelley Permission to use copy and distribute this software and its documentation for any purpose with or without fee is hereby granted provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation Permission to modify the software is granted but not the right to distribute the complete modified source code Modifications are to be distributed as patches to the released version Permission to distribute binaries produced by compiling modified sources is granted
109. efault sampling is set to 10 isolines per u or v axis A higher sampling rate will produce more accurate plots but will take longer These parameters have no effect on data file plotting An isoline is a curve parameterized by one of the surface parameters while the other surface parameter is fixed Isolines provide a simple means to display a surface By fixing the u parameter of surface s u v the iso u lines of the form c v s u0 v are produced and by fixing the v parameter the iso v lines of the form c u s u v0 are produced When a function surface plot is being done without the removal of hidden lines set samples controls the number of points sampled along each isoline see set samples and set hidden3d The contour algorithm assumes that a function sample occurs at each isoline intersection so change in samples as well as isosamples may be desired when changing the resolution of a function surface contour 34 22 Key The set key enables a key or legend describing plots on a plot The contents of the key i e the names given to each plotted data set and function and samples of the lines and or symbols used to represent them are determined by the title and with options of the s plot command Please see plot title and plot with for more information Syntax set key left right top bottom outside below lt position gt Left Right no reverse samplen lt sample_length gt spacing lt vertical_spacing gt
110. efaults to a 16 dotted line gnuplot borderDashes 0 gnuplot axisDashes 16 gnuplot linelDashes 0 gnuplot line2Dashes 42 gnuplot line3Dashes 13 gnuplot line4Dashes 44 gnuplot line5Dashes 15 gnuplot line6Dashes 4441 gnuplot line7Dashes 42 gnuplot line8Dashes 13 34 49 70 Xlib The xlib terminal driver supports the X11 Windows System It generates gnulib x11 commands set term x11 behaves similarly to set terminal xlib set output gnuplot_x11 xlib has no options but see x11 34 50 Tics The set tics command can be used to change the tics to be drawn outwards Syntax set tics lt direction gt show tics where lt direction gt may be in the default or out See also set xtics for more control of major labelled tic marks and set mxtics for control of minor tic marks 34 51 Ticslevel Using splot one can adjust the relative height of the vertical Z axis using set ticslevel The numeric argument provided specifies the location of the bottom of the scale as a fraction of the z range above 99 the xy plane The default value is 0 5 Negative values are permitted but tic labels on the three axes may overlap To place the xy plane at a position pos on the z axis ticslevel should be set equal to pos zmin zmin zmax Syntax set ticslevel lt level gt show tics See also set view 34 52 Ticscale The size of the tic marks can be adjusted with set ticscale Syn
111. egment will print the coordinates of its midpoint to stdout Advanced actions can happen instead if the user supplies a procedure named user_gnuplot_coordinates which takes the following arguments win id xls yls x2s y2s xle yle x2e y2e xlm ylm x2m y2m the name of the canvas and the id of the line segment followed by the coordinates of its start and end point in the two possible axis ranges the coordinates of the midpoint are only filled for logarithmic axes The current version of tkcanvas supports neither multiplot nor replot 34 49 63 Tpic The tpic terminal driver supports the LaTeX picture environment with tpic specials It is an alternative to the latex and eepic terminal drivers Options are the point size line width and dot dash interval Syntax set terminal tpic lt pointsize gt lt linewidth gt lt interval gt where pointsize and linewidth are integers in milli inches and interval is a float in inches If a non positive value is specified the default is chosen pointsize 40 linewidth 6 interval 0 1 All drivers for LaTeX offer a special way of controlling text positioning If any text string begins with you also need to include a at the end of the text and the whole text will be centered both 93 horizontally and vertically by LaTeX If the text string begins with you need to continue it with a position specification up to two out of t b l r f the text itself and finally
112. en it must be at the end with size if present last The size is needed to select a size for the font even if the font name includes size information For example set term mp cmtt12 selects cmtt12 shrunk to the default size 10 This is probably not what you want or you would have used cmtt10 The following common ascii characters need special treatment in TeX amp hs 23 l lt gt a de NG and The five characters amp and can simply be escaped e g The three characters lt gt and can be wrapped in math mode e g lt The remainder require some TeX work arounds Any good book on TeX will give some guidance If you type your labels inside double quotes backslashes in TeX code need to be escaped doubled Using single quotes will avoid having to do this but then you cannot use n for line breaks As of this writing version 3 7 of gnuplot processess titles given in a plot command differently than in other places and backslashes in TeX commands need to be doubled regardless of the style of quotes Metapost pictures are typically used in TeX documents Metapost deals with fonts pretty much the same way TeX does which is different from most other document preparation programs If the picture is included in a LaTeX document using the graphics package or in a plainTeX document via epsf tex and then converted to PostScript with dvips or other dvi to ps converter the text in the plot will usually b
113. enuplot An Interactive Plotting Program Thomas Williams amp Colin Kelley Version 3 7 organized by David Denholm Major contributors alphabetic order Hans Bernhard Broeker John Campbell Robert Cunningham David Denholm Gershon Elber Roger Fearick Carsten Grammes Lucas Hart Lars Hecking Thomas Koenig David Kotz Ed Kubaitis Russell Lang Alexander Lehmann Alexander Mai Carsten Steger Tom Tkacik Jos Van der Woude James R Van Zandt Alex Woo Copyright C 1986 1993 1998 Thomas Williams Colin Kelley Mailing list for comments info gnuplotCdartmouth edu Mailing list for bug reports bug gnuplotCdartmouth edu This manual was prepared by Dick Crawford 3 December 1998 Contents I Gnuplot 1 1 Copyright 1 2 Introduction 1 3 Seeking assistance 2 4 What s New in version 3 7 3 5 Batch Interactive Operation 4 6 Command line editing 4 7 Comments 5 8 Coordinates 5 9 Environment 6 10 Expressions 6 10 31 Functions s s ites 2 eee BEGG ewe ds A A AAN Sw Og 7 10 2 Opetators 2 3 ate oe eo BOS eo ee Eee E meme eee ee ada eas 9 10 21 UaKy eee ee ee a we Seas A a a ds eos has A aa a 9 10 22 Binary ce eR RS ENN A RR SSI LE EES Ee A Ee ee 9 10 23 1 O ete a a yee ee a on A 10 10 3 User defined iiri 4 A Se ee a Oe a ae 11 11 Glossary 11 12 Plotting 12 13 Start up 12 14 Substitution 12 15 Syntax 13 16 Time Date data 14 II Commands 14 17 Cd 15 18 Call 19 Clear 20 Exit 21 Fit 21 1 Adjustable parameters 21
114. er pixel gray a portable graymap three bits per pixel and color a portable pixmap color four bits per pixel The output of this driver can be used with Jef Poskanzer s excellent PBMPLUS package which provides programs to convert the above PBMPLUS formats to GIF TIFF MacPaint Macintosh PICT PCX X11 bitmap and many others PBMPLUS may be obtained from ftp x org The relevant files have names that begin with netpbm 1mar1994 p1 they reside in contrib utilities The package can probably also be obtained from one of the many sites that mirrors ftp x org Examples set terminal pbm small monochrome defaults set size 2 2 set terminal pbm color medium 34 49 47 Dospc The dospc terminal driver supports PCs with arbitrary graphics boards which will be automatically detected It should be used only if you are not using the gcc or Zortec C C compilers 34 49 48 Pm The pm terminal driver provides an OS 2 Presentation Manager window in which the graph is plotted The window is opened when the first graph is plotted This window has its own online help as well as facilities for printing copying to the clipboard and some line type and color adjustments The multiplot option is supported Syntax set terminal pm server n persist widelines enhanced title If persist is specified each graph appears in its own window and all windows remain open after gnuplot exits If server is specified all graphs appear in the same win
115. errors to some more practical estimates of parameter uncertainties or evaluate the significance of the correlation matrix Note that fit in common with most NLLS implementations minimizes the weighted sum of squared distances y f x 2 It does not provide any means to account for errors in the values of x only in y Also any outliers data points outside the normal distribution of the model will have an exaggerated effect on the solution 21 4 Fit controlling There are a number of gnuplot variables that can be defined to affect fit Those which can be defined once gnuplot is running are listed under control_variables while those defined before starting gnuplot are listed under environment_variables 21 4 1 Control variables The default epsilon limit le 5 may be changed by declaring a value for FIT_LIMIT When the sum of squared residuals changes between two iteration steps by a factor less than this number epsilon the fit is considered to have converged The maximum number of iterations may be limited by declaring a value for FIT_MAXITER A value of 0 or not defining it at all means that there is no limit If you need even more control about the algorithm and know the Marquardt Levenberg algorithm well there are some more variables to influence it The startup value of lambda is normally calculated automatically from the ML matrix but if you want to you may provide your own one with FIT_START_LAMBDA
116. es style displays a vertical line from the x axis not the graph border or from the grid base for splot to each point 34 47 10 Lines The lines style connects adjacent points with straight line segments 34 47 11 Linespoints The linespoints style does both lines and points that is it draws a small symbol at each point and then connects adjacent points with straight line segments The command set pointsize may be used to change the size of the points See set pointsize for its usage linespoints may be abbreviated Ip 34 47 12 Points The points style displays a small symbol at each point The command set pointsize may be used to change the size of the points See set pointsize for its usage 34 47 13 Steps The steps style is only relevant to 2 d plotting It connects consecutive points with two line segments the first from x1 y1 to x2 y1 and the second from x2 y1 to x2 y2 65 34 47 14 Vector The vector style draws a vector from x y to x xdelta y ydelta Thus it requires four columns of data It also draws a small arrowhead at the end of the vector The vector style is still experimental it doesn t get clipped properly and other things may also be wrong with it Use it at your own risk 34 47 15 Xerrorbars The xerrorbars style is only relevant to 2 d data plots xerrorbars is like dots except that a horizontal error bar is also drawn At each point x y a line is drawn from xlow y to xhigh y or from
117. et autoscale xy This sets autoscaling of the x y z x2 and y2 axes set autoscale This disables autoscaling of the x y z x2 and y2 axes set noautoscale This disables autoscaling of the z axis only set noautoscale z 34 3 1 Parametric mode When in parametric mode set parametric the xrange is as fully scalable as the y range In other words in parametric mode the x axis can be automatically scaled to fit the range of the parametric function that is being plotted Of course the y axis can also be automatically scaled just as in the non parametric case If autoscaling on the x axis is not set the current x range is used Data files are plotted the same in parametric and non parametric mode However there is a difference in mixed function and data plots in non parametric mode with autoscaled x the x range of the datafile controls the x range of the functions in parametric mode it has no influence For completeness a last command set autoscale t is accepted However the effect of this scaling is very minor When gnuplot determines that the t range would be empty it makes a small adjustment if autoscaling is true Otherwise gnuplot gives an error Such behavior may in fact not be very useful and the command set autoscale t is certainly questionable splot extends the above ideas as you would expect If autoscaling is set then x y and z ranges are computed and each axis scaled to fit the resulting data 34 3 2 Polar mod
118. ey is altered from its default configuration The first contour linetype or only contour linetype when clabel is off is the surface linetype 1 contour points are the same style as surface points See also set contour 42 34 9 Clip gnuplot can clip data points and lines that are near the boundaries of a graph Syntax set clip lt clip type gt set noclip lt clip type gt show clip Three clip types are supported by gnuplot points one and two One two or all three clip types may be active for a single graph The points clip type forces gnuplot to clip actually not plot at all data points that fall within but too close to the boundaries This is done so that large symbols used for points will not extend outside the boundary lines Without clipping points near the boundaries the plot may look bad Adjusting the x and y ranges may give similar results Setting the one clip type causes gnuplot to draw a line segment which has only one of its two endpoints within the graph Only the in range portion of the line is drawn The alternative is to not draw any portion of the line segment Some lines may have both endpoints out of range but pass through the graph Setting the two clip type allows the visible portion of these lines to be drawn In no case is a line drawn outside the graph The defaults are noclip points clip one and noclip two To check the state of all forms of clipping use show clip For backward compati
119. f set ytics 12345 12345 000 set format y 2t 10 03T set ytic 12345 1 23 107 04 set format y s 10 1 S set ytic 12345 12 345 10 3 set format y s cg set ytic 12345 12 345 kg set format y 0P pi set ytic 6 283185 2 pi set format y 0P set ytic 50 50 set log y 2 set format y 1 set ytics 1 2 3 displays 1 0 1 0 and 1 5 since 3 is 1 5 271 There are some problem cases that arise when numbers like 9 999 are printed with a format that requires both rounding and a power If the data type for the axis is time date the format string must contain valid codes for the strftime function outside of gnuplot type man strftime See set timefmt for a list of the allowed input format codes 34 16 2 Time date specifiers In time date mode the acceptable formats are 48 Tic mark label Date Time Format Specifiers Format Explanation ha abbreviated name of day of the week nA full name of day of the week b or h abbreviated name of the month 7B full name of the month 2d day of the month 1 31 D shorthand for m d y ZH or k hour 0 24 ZI or 1 hour 0 12 hj day of the year 1 366 m month 1 12 cM minute 0 60 p am or pm Ar shorthand for 1 M S p AR shorthand for H M 8 second 0 60 YT shorthand for H 7 M S ZU week of the year week starts on Sunday hw day of the week 0 6 Sunday 0 AW week of the y
120. f position title justification etc can be controlled by set key Please see set key for details Examples This plots y x with the title x plot x This plots x squared with title x 2 and file data 1 with title measured data plot x 2 title x72 data 1 t measured data This puts an untitled circular border around a polar graph set polar plot my_function t 1 notitle 26 6 With Functions and data may be displayed in one of a large number of styles The with keyword provides the means of selection Syntax with lt style gt linestyle ls lt line_style gt linetype 1t lt line_type gt linewidth lw lt line_width gt pointtype pt lt point_type gt pointsize ps lt point_size gt where lt style gt is either lines points linespoints impulses dots steps fsteps histeps error bars xerrorbars yerrorbars xyerrorbars boxes boxerrorbars boxxyerrorbars financebars candlesticks or vector Some of these styles require additional information See set style lt style gt for details of each style Default styles are chosen with the set function style and set data style commands By default each function and data file will use a different line type and point type up to the maximum number of available types All terminal drivers support at least six different point types and re use them in order if more are required The LaTeX driver supplies an additional six point types
121. f the DISPLAY environment variable is set if the TERM environment variable is set to xterm or if the display command line option is used Syntax set terminal x11 reset lt n gt Multiple plot windows are supported set terminal x11 lt n gt directs the output to plot window number n If n gt 0 the terminal number will be appended to the window title and the icon will be labeled gplt lt n gt The active window may distinguished by a change in cursor from default to crosshair Plot windows remain open even when the gnuplot driver is changed to a different device A plot window can be closed by pressing the letter q while that window has input focus or by choosing close from a window manager menu All plot windows can be closed by specifying reset which actually terminates the subprocess which maintains the windows unless persist was specified Plot windows will automatically be closed at the end of the session unless the persist option was given The size or aspect ratio of a plot may be changed by resizing the gnuplot window Linewidths and pointsizes may be changed from within gnuplot with set linestyle For terminal type x11 gnuplot accepts when initialized the standard X Toolkit options and resources such as geometry font and name from the command line arguments or a configuration file See the X 1 man page or its equivalent for a description of such options A number of other gnuplot options are available for the x11
122. f the contour lines may be written to a file and then read with plot to take advantage of plot s additional formatting capabilities 37 Test test creates a display of line and point styles and other useful things appropriate for the terminal you are using Syntax test 114 38 Update This command writes the current values of the fit parameters into the given file formatted as an initial value file as described in the fitsection This is useful for saving the current values for later use or for restarting a converged or stopped fit Syntax update lt filename gt lt filename gt If a second filename is supplied the updated values are written to this file and the original parameter file is left unmodified Otherwise if the file already exists gnuplot first renames it by appending old and then opens a new file That is update fred behaves the same as rename fred fred old update fred old fred On DOS and other systems that use the twelve character filename ext naming convention ext will be old and filename will be related hopefully recognizably to the initial name Renaming is not done at all on VMS systems since they use file versioning Please see fit for more information Part III Graphical User Interfaces Several graphical user interfaces have been written for gnuplot and one for win32 is included in this distribution In addition there is a Macintosh interface at ftp f
123. file This example plots the data in the file population dat and a theoretical curve pop x 103x exp 1965 x 10 plot 1960 1990 population dat pop x The file population dat might contain Gnu population in Antarctica since 1965 1965 103 1970 55 1975 34 1980 24 1985 10 26 1 3 Index The index keyword allows only some of the data sets in a multi data set file to be plotted Syntax plot file index lt m gt lt n gt lt p gt Data sets are separated by pairs of blank records index lt m gt selects only set lt m gt index lt m gt lt n gt selects sets in the range lt m gt to lt n gt and index lt m gt lt n gt lt p gt selects indices lt m gt lt m gt lt p gt 27 lt m gt 2 lt p gt etc but stopping at lt n gt Following C indexing the index 0 is assigned to the first data set in the file Specifying too large an index results in an error message If index is not specified all sets are plotted as a single data set Example plot file index 4 5 26 1 4 Smooth gnuplot includes a few general purpose routines for interpolation and approximation of data these are grouped under the smooth option More sophisticated data processing may be performed by preprocessing the data externally or by using fit with an appropriate model Syntax smooth unique csplines acsplines bezier sbezier unique plots the data after making them monotonic Each of the other routines u
124. filter that converts scattered data to a grid data set More sophisticated approaches to this problem exist and should be used to preprocess the data outside gnuplot if this simple solution is found inadequate The z values are found by weighting all data points not by interpolating between nearby data points also edge effects may produce unexpected and or undesired results In some cases small norm values produce a grid point reflecting the average of distant data points rather than a local average while large values of norm may produce steps with several grid points having the same value as the closest data point rather than making a smooth transition between adjacent data points Some areas of a grid may be filled by extrapolation to an arbitrary boundary condition The variables are not normalized consequently the units used for x and y will affect the relative weights of points in the x and y directions Examples set dgrid3d 10 10 1 defaults set dgrid3d 4 The first specifies that a grid of size 10 by 10 is to be constructed using a norm value of 1 in the weight computation The second only modifies the norm changing it to 4 34 14 Dummy The set dummy command changes the default dummy variable names Syntax set dummy lt dummy var gt lt dummy var gt show dummy By default gnuplot assumes that the independent or dummy variable for the plot command is t if in parametric or polar mode or x otherwise Sim
125. ginning of the command file to the reread command But this is not necessarily a disaster reread can be very useful when used in conjunction with if See if for details The reread command has no effect if input from standard input Examples Suppose the file looper contains the commands a a l plot sin x a pause 1 if a lt 5 reread and from within gnuplot you submit the commands a 0 load looper The result will be four plots separated by the pause message Suppose the file data contains six columns of numbers with a total yrange from 0 to 10 the first is x and the next are five different functions of x Suppose also that the file plotter contains the commands c_p c_pti plot 0 using 1 c_p with lines linetype c_p if c_p lt n_p reread 36 and from within gnuplot you submit the commands n_p 6 c_p 1 set nokey set yrange 0 10 set multiplot call plotter data set nomultiplot The result is a single graph consisting of five plots The yrange must be set explicitly to guarantee that the five separate graphs drawn on top of each other in multiplot mode will have exactly the same axes The linetype must be specified otherwise all the plots would be drawn with the same type 32 Reset The reset command causes all options that can be set with the set command to take on their default values The only exceptions are that the terminal set with set term and the output file set with set output
126. given the lowest unused tag value is assigned automatically The tag can be used to delete or change a specific arrow To change any attribute of an existing arrow use the set arrow command with the appropriate tag and specify the parts of the arrow to be changed The lt position gt s are specified by either x y or x y z and may be preceded by first second graph or screen to select the coordinate system Unspecified coordinates default to 0 The endpoints can be specified in one of four coordinate systems first or second axes graph or screen See coordinates for details A coordinate system specifier does not carry over from the from position to the to position Arrows outside the screen boundaries are permitted but may cause device errors Specifying nohead produces an arrow drawn without a head a line segment This gives you yet another way to draw a line segment on the plot By default arrows have heads 38 The line style may be selected from a user defined list of line styles see set linestyle or may be defined here by providing values for lt line_type gt an index from the default list of styles and or lt line_width gt which is a multiplier for the default width Note however that if a user defined line style has been selected its properties type and width cannot be altered merely by issuing another set arrow command with the appropriate index and lt or lw Examples To set an arrow pointing from the origin
127. gonal element of unit magnitude with a sign depending on whether the relation is proportional or inversely proportional The smaller the magnitudes of the off diagonal elements the closer the estimates of the standard deviation of each parameter would be to the asymptotic standard error 21 3 2 Practical guidelines If you have a basis for assigning weights to each data point doing so lets you make use of additional knowledge about your measurements e g take into account that some points may be more reliable than others That may affect the final values of the parameters Weighting the data provides a basis for interpreting the additional fit output after the last iteration Even if you weight each point equally estimating an average standard deviation rather than using a weight of 1 makes WSSR a dimensionless variable as chisquare is by definition Each fit iteration will display information which can be used to evaluate the progress of the fit An indicates that it did not find a smaller WSSR and is trying again The sum of squares of residuals also called chisquare is the WSSR between the data and your fitted function fit has minimized that 20 At this stage with weighted data chisquare is expected to approach the number of degrees of freedom data points minus parameters The WSSR can be used to calculate the reduced chisquare WSSR ndf or stdfit the standard deviation of the fit sqrt WSSR ndf Both of thes
128. he parameters to be fitted by all means do so That helps a lot because the problem is no longer nonlinear and should converge with only a small number of iterations perhaps just one Some prescriptions for analysing data given in practical experimentation courses may have you first fit some functions to your data perhaps in a multi step process of accounting for several aspects of the underlying theory one by one and then extract the information you really wanted from the fitting parameters of those functions With fit this may often be done in one step by writing the model function directly in terms of the desired parameters Transforming data can also quite often be avoided though sometimes at the cost of a more difficult fit problem If you think this contradicts the previous paragraph about simplifying the fit function you are correct A singular matrix message indicates that this implementation of the Marquardt Levenberg algorithm can t calculate parameter values for the next iteration Try different starting values writing the function in another form or a simpler function Finally a nice quote from the manual of another fitting package fudgit that kind of summarizes all these issues Nonlinear fitting is an art 23 22 Help The help command displays on line help To specify information on a particular topic use the syntax help lt topic gt If lt topic gt is not specified a short message is printed about gnuplot
129. he y direction set terminal tgif 1 2 portrait 1 plot in the x 92 and 2 in the y direction set terminal tgif landscape 3 3 landscape 3 plots in both directions 34 49 62 Tkcanvas This terminal driver generates Tk canvas widget commands based on Tcl Tk default or Perl To use it rebuild gnuplot after uncommenting or inserting the appropriate line in term h then gnuplot gt set term tkcanvas perltk interactive gnuplot gt set output plot file After invoking wish execute the following sequence of Tcl Tk commands source plot file canvas c pack c gnuplot c Or for Perl Tk use a program like this use Tk my top MainWindow gt new my c top gt Canvas c gt pack do plot pl gnuplot gt c MainLoop The code generated by gnuplot creates a procedure called gnuplot that takes the name of a canvas as its argument When the procedure is called it clears the canvas finds the size of the canvas and draws the plot in it scaled to fit For 2 dimensional plotting plot two additional procedures are defined gnuplot_plotarea will return a list containing the borders of the plotting area xleft xright ytop ybot in canvas screen coordinates while the ranges of the two axes xlmin xlmax ylmin ylmax x2min x2max y2min y2max in plot coordinates can be obtained calling gnuplot_axisranges If the interactive option is specified mouse clicking on a line s
130. hen the default range is 0 360 and the independent variable has units of degrees This is particularly useful for plots of data files The angle setting also applies to 3 d mapping as set via the set mapping command Syntax set angles degrees radians show angles The angle specified in set grid polar is also read and displayed in the units specified by set angles set angles also affects the arguments of the machine defined functions sin x cos x and tan x and the outputs of asin x acos x atan x atan2 x and arg x It has no effect on the arguments of hyperbolic functions or Bessel functions However the output arguments of inverse hyperbolic functions of complex arguments are affected if these functions are used set angles radians must be in effect to maintain consistency between input and output arguments x 1 0 0 1 set angles radians y sinh x print y prints 1 16933 0 154051 print asinh y prints 1 0 0 1 but set angles degrees y sinh x print y prints 1 16933 0 154051 print asinh y prints 57 29578 5 729578 34 2 Arrow Arbitrary arrows can be placed on a plot using the set arrow command Syntax set arrow lt tag gt from lt position gt to lt position gt no head linestyle ls lt line_style gt linetype 1t lt line_type gt linewidth lw lt line_width set noarrow lt tag gt show arrow lt tag gt is an integer that identifies the arrow If no tag is
131. here t is an angle of rotation The trange controls the domain the angle of the function and the x and y ranges control the range of the graph in the x and y directions Each of these ranges as well as the rrange may be autoscaled or set explicitly See set xrange for details of all the set range commands Example set polar 61 plot t sin t plot 2 pi 2 pi 3 3 3 3 t sin t The first plot uses the default polar angular domain of 0 to 2 pi The radius and the size of the graph are scaled automatically The second plot expands the domain and restricts the size of the graph to 3 3 in both directions You may want to set size square to have gnuplot try to make the aspect ratio equal to unity so that circles look circular 34 43 Rmargin The command set rmargin sets the size of the right margin Please see set margin for details 34 44 Rrange The set rrange command sets the range of the radial coordinate for a graph in polar mode Please see set xrange for details 34 45 Samples The sampling rate of functions or for interpolating data may be changed by the set samples command Syntax set samples lt samples_1 gt lt samples_2 gt show samples By default sampling is set to 100 points A higher sampling rate will produce more accurate plots but will take longer This parameter has no effect on data file plotting unless one of the interpo lation approximation options is used See plot smooth re 2 d data
132. hese should be the x coordinate most likely a date and the opening low high 64 and closing prices The symbol is a vertical line segment located horizontally at the x coordinate and limited vertically by the high and low prices A horizontal tic on the left marks the opening price and one on the right marks the closing price The length of these tics may be changed by set bar The symbol will be unchanged if the high and low prices are interchanged See set bar and candlesticks 34 47 7 Fsteps The fsteps style is only relevant to 2 d plotting It connects consecutive points with two line segments the first from x1 y1 to x1 y2 and the second from x1 y2 to x2 y2 34 47 8 Histeps The histeps style is only relevant to 2 d plotting It is intended for plotting histograms Y values are assumed to be centered at the x values the point at x1 is represented as a horizontal line from x0 x1 2 y1 to x14 x2 2 y1 The lines representing the end points are extended so that the step is centered on at x Adjacent points are connected by a vertical line at their average x that is from x1 x2 2 y1 to x14x2 2 y2 If autoscale is in effect it selects the xrange from the data rather than the steps so the end points will appear only half as wide as the others histeps is only a plotting style gnuplot does not have the ability to create bins and determine their population from some data set 34 47 9 Impulses The impuls
133. hite space may be embedded within the time date string Tf you use tabs as a separator some trial and error may be necessary to discover how your system treats them The following example demonstrates time date plotting Suppose the file data contains records like 03 21 95 10 00 6 02e23 This file can be plotted by set xdata time set timefmt m d y set xrange 03 21 95 03 22 95 set format x m d set timefmt m 4d y H M plot data using 1 3 which will produce xtic labels that look like 03 21 See the descriptions of each command for more details Part II Commands This section lists the commands acceptable to gnuplot in alphabetical order Printed versions of this document contain all commands on line versions may not be complete Indeed on some systems there may be no commands at all listed under this heading Note that in most cases unambiguous abbreviations for command names and their options are permis sible i e p f x w 1 instead of plot f x with lines In the syntax descriptions braces denote optional arguments and a vertical bar separates mu tually exclusive choices 15 17 Cd The cd command changes the working directory Syntax cd lt directory name gt The directory name must be enclosed in quotes Examples cd subdir cd e DOS users must use single quotes backslash has special significance inside double quotes For example cd c newdat
134. ic labels is controlled by set format unless the explicit text of a labels is included in the set xtic lt label gt form Minor unlabelled tics can be added by the set mxtics command In case of timeseries data position values must be given as quoted dates or times according to the format timefmt If the lt start gt lt incr gt lt end gt form is used lt start gt and lt end gt must be given according to timefmt but lt incr gt must be in seconds Times will be written out according to the format given on set format however Examples set xdata time set timefmt d m set format x b d set xrange 01 12 06 12 set xtics 01 12 172800 05 12 set xdata time set timefmt d m set format x b d set xrange 01 12 06 12 set xtics 01 12 03 12 05 12 Both of these will produce tics Dec 1 Dec 3 and Dec 5 but in the second example the tic at Dec 3 will be unlabelled 34 76 Xzeroaxis The set xzeroaxis command draws a line at y 0 For details please see set zeroaxis 34 77 Y2data The set y2data command sets y2 right hand axis data to timeseries dates times Please see set xdata 34 78 Y2dtics The set y2dtics command changes tics on the y2 right hand axis to days of the week Please see set xdtics for details 34 79 Y2label The set y2dtics command sets the label for the y2 right hand axis Please see set xlabel 34 80 Y2mtics The set y2mtics comma
135. ich are 512 and 768 pixels respectively Their vertical range is 575 pixels There are no options for these drivers 34 49 2 Aifm Several options may be set in aifm the Adobe Illustrator 3 0 driver Syntax set terminal aifm lt color gt lt fontname gt lt fontsize gt lt color gt is either color or monochrome lt fontname gt is the name of a valid PostScript font lt fontsize gt is the size of the font in PostScript points before scaling by the set size command Selecting default sets all options to their default values monochrome Helvetica and 14pt Since AI does not really support multiple pages multiple graphs will be drawn directly on top of one another However each graph will be grouped individually making it easy to separate them inside AI just pick them up and move them Examples set term aifm set term aifm 22 set size 0 7 1 4 set term aifm color Times Roman 14 34 49 3 Amiga The amiga terminal for Commodore Amiga computers allows the user to plot either to a screen default or if Kickstart 3 0 or higher is installed to a window on the current public screen The font and its size can also be selected Syntax set terminal amiga screen window lt fontname gt lt fontsize gt The default font is 8 point topaz The screen option uses a virtual screen so it is possible that the graph will be larger than the screen 34 49 4 Apollo The apollo terminal driver suppor
136. ich are 75 dpi and no compression Rasterization at the higher resolutions may require a large amount of memory 34 49 30 Hpgl The hpgl driver produces HPGL output for devices like the HP7475A plotter There are two options which can be set the number of pens and eject which tells the plotter to eject a page when done The default is to use 6 pens and not to eject the page when done The international character sets ISO 8859 1 and CP850 are recognized via set encoding iso_8859_1 or set encoding cp850 see set encoding for details Syntax set terminal hpgl lt number_of_pens gt eject The selection set terminal hpgl 8 eject is equivalent to the previous hp7550 terminal and the selection set terminal hpgl 4 is equivalent to the previous hp7580b terminal The pcl5 driver supports the Hewlett Packard Laserjet III It actually uses HPGL 2 but there is a name conflict among the terminal devices It has several options Syntax set terminal pcl5 lt mode gt lt font gt lt fontsize gt where lt mode gt is landscape or portrait lt font gt is stick univers or cg_times and lt fontsize gt is the size in points With pcl5 international characters are handled by the printer you just put the appropriate 8 bit char acter codes into the text strings You don t need to bother with set encoding HPGL graphics can be imported by many software packages 34 49 31 Hpljii The hpljii terminal driver supports the HP
137. ictures are stored The mf terminal has no options 34 49 39 1 METAFONT Instructions Set your terminal to METAFONT set terminal mf Select an output file e g set output myfigures mf Create your pictures Each picture will generate a separate character Its default size will be 5 3 inches You can change the size by saying set size 0 5 0 5 or whatever fraction of the default size you want to have Quit gnuplot Generate a TFM and GF file by running METAFONT on the output of gnuplot Since the picture is quite large 5 3 in you will have to use a version of METAFONT that has a value of at least 150000 for memmax On Unix systems these are conventionally installed under the name bigmf For the following assume that the command virmf stands for a big version of METAFONT For example Invoke METAFONT 82 virm amp plain Select the output device At the METAFONT prompt type mode CanonCx or whatever printer you use Optionally select a magnification mag 1 or whatever you wish Input the gnuplot file input myfigures mf On a typical Unix machine there will usually be a script called mf that executes virmf amp plain so you probably can substitute mf for virmf amp plain This will generate two files mfput tfm and mfput ef where indicates the resolution of your device The above can be conveniently achieved by typing everything on the command line e g v
138. if the data in the file are not in the required order mapping has no effect on plot 34 29 Margin The computed margins can be overridden by the set margin commands show margin shows the current settings Syntax set bmargin lt margin gt set lmargin lt margin gt set rmargin lt margin gt set tmargin lt margin gt show margin The units of lt margin gt are character heights or widths as appropriate A positive value defines the absolute size of the margin A negative value or none causes gnuplot to revert to the computed value Normally the margins of a plot are automatically calculated based on tics tic labels axis labels the plot title the timestamp and the size of the key if it is outside the borders If however tics are attached to the axes set xtics axis for example neither the tics themselves nor their labels will be included in either the margin calculation or the calculation of the positions of other text to be written in the margin This can lead to tic labels overwriting other text if the axis is very close to the border 34 30 Missing The set missing command allows you to tell gnuplot what character is used in a data file to denote missing data Syntax set missing lt character gt show missing Example set missing would mean that when plotting a file containing 11 2 3 2 the middle line would be ignored There is no default character for missing 34 31 Multiplot The
139. ignored sin x any sin x sine of x sinh x any sinh x hyperbolic sine x in radians sqrt x any yz square root of x tan x any tana tangent of x tanh x any tanh z hyperbolic tangent of x in radians A few additional functions are also available other gnuplot functions Function Arguments Returns column x int column x during datafile manipulation tm_hour x int the hour tm_mday x int the day of the month tm_min x int the minute tm_mon x int the month tm_sec x int the second tm_wday x int the day of the week tm_yday x int the day of the year tm_year x int the year valid x int test validity of column x during datafile manip 10 2 Operators The operators in gnuplot are the same as the corresponding operators in the C programming language except that all operators accept integer real and complex arguments unless otherwise noted The operator exponentiation is supported as in FORTRAN Parentheses may be used to change order of evaluation 10 2 1 Unary The following is a list of all the unary operators and their usages Unary Operators Symbol Example Explanation a unary minus a unary plus no operation 7 a one s complement la logical negation a factorial 3 call arg column during using manipulation Starred explanations indicate that the operator requires an integer argument Operator precedence is the same as i
140. ilarly the independent variables for the splot command are u and v in parametric mode splot cannot be used in polar mode or x and y otherwise It may be more convenient to call a dummy variable by a more physically meaningful or conventional name For example when plotting time functions set dummy t plot sin t cos t At least one dummy variable must be set on the command set dummy by itself will generate an error message Examples set dummy u v set dummy s The second example sets the second variable to s 46 34 15 Encoding The set encoding command selects a character encoding Valid values are default which tells a terminal to use its default iso_8859_1 known in the PostScript world as ISO Latin1 which is used on many Unix workstations and with MS Windows cp850 for OS 2 and cp437 for MS DOS Syntax set encoding lt value gt show encoding Note that encoding is not supported by all terminal drivers and that the device must be able to produce the desired non standard characters 34 16 Format The format of the tic mark labels can be set with the set format command Syntax set format lt axes gt lt format string gt set format lt axes gt lt format string gt show format where lt axes gt is either x y Z xy x2 y2 or nothing which is the same as xy The length of the string representing a tic mark after formatting with printf is restricted to 100 characte
141. ilter for Word for Windows 6 0c can accept rotated text but the DRAW editor within Word cannot If you edit a graph for example to label a curve all rotated text is restored to horizontal The Y axis label will then extend beyond the clip boundary With norotate the Y axis label starts in a less attractive location but the page can be edited without damage The rotate option confirms the default behavior 34 49 9 5 Solid The solid option may be used to disable dashed line styles in the plots This is useful when color is enabled and the dashing of the lines detracts from the appearance of the plot The dashed option confirms the default behavior which gives a different dash pattern to each curve 34 49 9 6 Size Default size of a CGM page is 32599 units wide and 23457 units high for landscape or 23457 units wide by 32599 units high for portrait 34 49 9 7 Width All distances in the CGM file are in abstract units The application that reads the file determines the size of the final page By default the width of the final page is assumed to be 6 inches 15 24 cm This distance is used to calculate the correct font size and may be changed with the width option The keyword should be followed by the width in points Here a point is 1 72 inch as in PostScript This unit is known as a big point in TeX gnuplot arithmetic can be used to convert from other units as follows set terminal cgm width 432 default set terminal cgm width 6 72 s
142. irmf amp plain mode CanonCX mag 1 input myfigures mf In this case the output files will be named myfigures tfm and myfigures 300gf Generate a PK file from the GF file using gftopk gftopk myfigures 300gf myfigures 300pk The name of the output file for gftopk depends on the DVI driver you use Ask your local TeX admin istrator about the naming conventions Next either install the TFM and PK files in the appropriate directories or set your environment variables properly Usually this involves setting TEXFONTS to include the current directory and doing the same thing for the environment variable that your DVI driver uses no standard name here This step is necessary so that TeX will find the font metric file and your DVI driver will find the PK file To include your pictures in your document you have to tell TeX the font font gnufigs myfigures Each picture you made is stored in a single character The first picture is character 0 the second is character 1 and so on After doing the above step you can use the pictures just like any other characters Therefore to place pictures 1 and 2 centered in your document all you have to do is centerline gnufigs char0 centerline gnufigs char1 in plain TeX For LaTeX you can of course use the picture environment and place the picture wherever you wish by using the makebox and put macros This conversion saves you a lot of time once you have generated the font
143. it and more See set key 7 Multiplots on a single logical page with set multiplot 8 Enhanced postscript driver with super subscripts and font changes This was a separate driver enhpost that was available as a patch for 3 5 9 Second axes use the top and right axes independently of the bottom and left both for plotting and labels See plot 10 Special datafile names and See plot special filenames 11 Additional coordinate systems for labels and arrows See coordinates 12 set size can try to plot with a specified aspect ratio 13 set missing now treats missing data correctly 14 The call command load with arguments 15 More flexible range commands with reverse and writeback keywords 16 set encoding for multi lingual encoding 17 New x11 driver with persistent and multiple windows 18 New plotting styles xerrorbars histeps financebars and more See set style 19 New tic label formats including 1 L which uses the mantissa and exponents to a given base for labels See set format 20 New drivers including cgm for inclusion into MS Office applications and gif for serving plots to the WEB 21 Smoothing and spline fitting options for plot See plot smooth 22 set margin and set origin give much better control over where a graph appears on the page 23 set border now controls each border individually 24 The new commands if and reread allow command loops 25 Point styles and sizes
144. ites include upgrading the X11 libraries from DEC or direct from MIT or defining ULTRIX_KLUDGE when compiling the x11 trm file Note that the kludge is not an ideal fix however The constant HUGE was incorrectly defined in the NeXT OS 2 0 operating system HUGE should be set to 1e38 in plot h This error has been corrected in the 2 1 version of NeXT OS Some older models of HP plotters do not have a page eject command PG The current HPGL driver uses this command in HPGL_reset This may need to be removed for these plotters The current PCL5 driver uses HPGL 2 for text as well as graphics This should be modified to use scalable PCL fonts On the Atari version it is not possible to send output directly to the printer using dev lp as output file since CRs are added to LFs in binary output As a work around write the output to a file and copy it to the printer afterwards using a shell command 116 On AIX 4 the literal NaNq in a datafile causes the special internal value not a number to be stored rather than setting an internal undefined flag A workaround is to use set missing NaNq There may be an up to date list of bugs since the release on the WWW page http www cs dartmouth edu gnuplot_info html Please report any bugs to bug gnuplot dartmouth edu
145. ize 640 330 GraphFont Arial 10 GraphColor 1 GraphToTop 1 GraphBackground 255 255 255 Border 0 0 0 0 0 Axis 192 192 192 2 2 Line1 0 0 255 0 0 Line2 0 255 0 0 1 Line3 255 0 0 0 2 Line4 255 0 255 0 3 Line5 0 0 128 0 4 The GraphFont entry specifies the font name and size in points The five numbers given in the Border Axis and Line entries are the Red intensity 0 255 Green intensity Blue intensity Color Linestyle and Mono Linestyle Linestyles are 0 SOLID 1 DASH 2 DOT 3 DASHDOT 4 DASHDOT DOT In the sample WGNUPLOT INI file above Line 2 is a green solid line in color mode or a dashed line in monochrome mode The default line width is 1 pixel If Linestyle is negative it specifies the width of a SOLID line in pixels Linel and any linestyle used with the points style must be SOLID with unit width 34 49 68 5 Windows3 0 Windows 3 1 is preferred but WGNUPLOT will run under Windows 3 0 with the following restrictions 1 COMMDLG DLL and SHELL DLL available with Windows 3 1 or Borland C 3 1 must be in the windows directory 2 WGNUPLOT HLP produced by Borland C 3 1 is in Windows 3 1 format You need to use the WINHELP EXE supplied with Borland C 3 1 96 3 It will not run in real mode due to lack of memory 4 TrueType fonts are not available in the graph window 5 Drag drop does not work 34 49 69 X11 gnuplot provides the x11 terminal type for use with X servers This terminal type is set automatically at startup i
146. kground color and linestyles to the initialization file WGNUPLOT INI 34 49 68 2 Printing In order of preference graphs may be be printed in the following ways 1 Use the gnuplot command set terminal to select a printer and set output to redirect output to a file 2 Select the Print command from the gnuplot graph window An extra command screendump does this from the text window 3 If set output PRN is used output will go to a temporary file When you exit from gnuplot or when you change the output with another set output command a dialog box will appear for you to select a printer port If you choose OK the output will be printed on the selected port passing unmodified through the print manager Tt is possible to accidentally or deliberately send printer output meant for one printer to an incompatible printer 34 49 68 3 Text menu The gnuplot text window has the following options on a pop up menu accessed by pressing the right mouse button or selecting Options from the system menu Copy to Clipboard copies marked text to the clipboard Paste copies text from the clipboard as if typed by the user Choose Font selects the font used in the text window System Colors when selected makes the text window honor the System Colors set using the Control Panel When unselected text is black or blue on a white background Update wgnuplot ini saves the current text window location text window size text window font and text window f
147. l drivers require that bounding box information be available before any plots can be made and the form given above guarantees that the bounding box will include the entire plot array rather than just the bounding box of the first plot set size and set origin refer to the entire plotting area used for each plot If you want to have the axes themselves line up you can guarantee that the margins are the same size with the set margin commands See set margin for their use Note that the margin settings are absolute in character units so the appearance of the graph in the remaining space will depend on the screen size of the display device e g perhaps quite different on a video display and a printer 34 32 Mx2tics Minor tic marks along the x2 top axis are controlled by set mx2tics Please see set mxtics 34 33 Mxtics Minor tic marks along the x axis are controlled by set mxtics They can be turned off with set nomxtics Similar commands control minor tics along the other axes Syntax set mxtics lt freq gt default set nomxtics show mxtics The same syntax applies to mytics mztics mx2tics and my2tics 58 lt freq gt is the number of sub intervals NOT the number of minor tics between major tics ten is the default for a linear axis so there are nine minor tics between major tics Selecting default will return the number of minor ticks to its default value If the axis is logarithmic the number of sub intervals will be
148. l styles will be changed to xyerrorbars before plotting For more information about error bars please see plot errorbars 34 47 1 Boxerrorbars The boxerrorbars style is only relevant to 2 d data plotting It is a combination of the boxes and yerrorbars styles The boxwidth will come from the fourth column if the y errors are in the form of ydelta and the boxwidth was not previously set equal to 2 0 set boxwidth 2 0 or from the fifth column if the y errors are in the form of ylow yhigh The special case boxwidth 2 0 is for four column data with y errors in the form ylow yhigh In this case the boxwidth will be calculated so that each box touches the adjacent boxes The width will also be calculated in cases where three column data are used The box height is determined from the y error in the same way as it is for the yerrorbars style either from y ydelta to y ydelta or from ylow to yhigh depending on how many data columns are provided 34 47 2 Boxes The boxes style is only relevant to 2 d plotting It draws a box centered about the given x coordinate from the x axis not the graph border to the given y coordinate The width of the box is obtained in one of three ways If it is a data plot and the data file has a third column this will be used to set the width of the box If not if a width has been set using the set boxwidth command this will be used If neither of these is available the width of each box will be calculated
149. label Note that double quotes must be used The same font will be used for both lines of course If you are not satisfied with the default position of an axis label use set label instead that command gives you much more control over where text is placed Please see set syntax for further information about backslash processing and the difference between single and double quoted strings 34 73 Xmtics The set xmtics commands converts the x axis tic marks to months of the year where 1 Jan and 12 Dec Overflows are converted modulo 12 to months The tics are returned to their default labels by set noxmtics Similar commands perform the same duties for the other axes Syntax set xmtics set noxmtics show xmtics The same syntax applies to x2mtics ymtics y2mtics and zmtics See also the set format command 34 74 Xrange The set xrange command sets the horizontal range that will be displayed A similar command exists for each of the other axes as well as for the polar radius r and the parametric variables t u and v Syntax set xrange lt min gt lt max gt no reverse no writeback show xrange where lt min gt and lt max gt terms are constants expressions or an asterisk to set autoscaling If the data are time date you must give the range as a quoted string according to the set timefmt format Any value omitted will not be changed 105 The same syntax applies to yrange zrange x2range y2range rrange
150. lease see set xlabel 34 66 X2mtics The set x2mtics command changes tics on the x2 top axis to months of the year Please see set xmtics for details 34 67 X2range The set x2range command sets the horizontal range that will be displayed on the x2 top axis Please see set xrange for details 34 68 X2tics The set x2tics command controls major labelled tics on the x2 top axis Please see set xtics for details 34 69 X2zeroaxis The set x2zeroaxis command draws a line at the origin of the x2 top axis y2 0 For details please see set zeroaxis 103 34 70 Xdata This command sets the datatype on the x axis to time date A similar command does the same thing for each of the other axes Syntax set xdata time show xdata The same syntax applies to ydata zdata x2data and y2data The time option signals that the datatype is indeed time date If the option is not specified the datatype reverts to normal See set timefmt to tell gnuplot how to read date or time data The time date is converted to seconds from start of the century There is currently only one timefmt which implies that all the time date columns must confirm to this format Specification of ranges should be supplied as quoted strings according to this format to avoid interpretation of the time date as an expression The function strftime type man strftime on unix to look it up is used to print tic mark labels gnuplot tries to figure out
151. line types and widths can be specified on the plot command Line types and widths can also be specified for grids borders tics and arrows See plot with Furthermore these types may be combined and stored for further use See set linestyle 26 Text labels tic labels and the time stamp can be written vertically by those terminals capable of doing so 5 Batch Interactive Operation gnuplot may be executed in either batch or interactive modes and the two may even be mixed together on many systems Any command line arguments are assumed to be names of files containing gnuplot commands with the exception of standard X11 arguments which are processed first Each file is loaded with the load command in the order specified gnuplot exits after the last file is processed When no load files are named gnuplot enters into an interactive mode The special filename is used to denote standard input Both the exit and quit commands terminate the current command file and load the next one until all have been processed Examples To launch an interactive session gnuplot To launch a batch session using two command files inputl and input2 gnuplot inputi input2 To launch an interactive session after an initialization file header and followed by another command file trailer gnuplot header trailer 6 Command line editing Command line editing is supported by the Unix Atari VMS MS DOS and OS 2 versions of gnuplot
152. low white and dark blue in monochrome mode black for 1 to 6 and white for 7 to 9 See plot with for details of lt linetype gt and lt pointtype gt The big option is a substitute for the bfig terminal in earlier versions which is no longer supported Examples set terminal fig monochrome small pointsmax 1000 defaults plot file dat with points linetype 102 pointtype 759 would produce circles with a blue outline of width 1 and yellow fill color plot file dat using 1 2 3 with err linetype 1 pointtype 554 would produce errorbars with black lines and circles filled red These circles are one layer above the lines at depth 9 by default To plot the error bars on top of the circles use plot file dat using 1 2 3 with err linetype 1 pointtype 2554 34 49 22 Gif The gif terminal driver generates output in GIF format It uses Thomas Boutell s gd library which is available from http www boutell com gd By default the gif terminal driver uses a shared Web friendy palette Syntax set terminal gif transparent interlace tiny small medium large giant size lt x gt lt y gt lt color0 gt lt color1 gt lt color2 gt 76 transparent instructs the driver to generate transparent GIFs The first color will be the transparent one interlace instructs the driver to generate interlaced GIFs The choice of fonts is tiny 5x8 pixels small 6x12 pixels medium 7x13 Bold large 8x16
153. m A ES A OS ee ee ts eta 86 A AQ TAO PIG a o AS eos wd gS GO GD Gy Sp Sp Gas alto Sade Mh OE Oh dt at te ee 86 34 49 50 Postscript o 3 54 bangs be de Aaa eee re Ge e ae a ad 87 34 49 50 1 Enhanced postscript 2 2 20 00 ee ee ee 87 34 49 50 2 Editing postscript 2 ee 88 34 49 51 Pslatexand pstex aetna A Be ha eo a os 88 31 49 52 PStrickSis su dul ra A Rs ah gt a eh ae a A wth at 89 IMA Ma ob doe a Se eee a AAA Se 89 34 49 54 Repis aco ee he Ae eee EER ee PRA SE Phase ee ARBRE Eee 90 34 49 5o REIDH was LAA ghee ee 90 34 4956 SUM oka Oe Ghee e REE Ee SE Pee ee See eee ee as 90 54 49 57 TEKA ho Pek A eRe SARA SOMO Ee Re da do a 90 34 49 58 Table esi iio E ii ad obs 2 A a a e SEs 90 34 49 5OSTEKAG occ te eR A A ee Re Oe ee as 90 94 49 60 Lexdrawis 0 ha Poe RR RE EES RE Re Pee ee ee a es 91 SA AJOL HL BIL AA sh ds Ga gi Sy Se Sy eH a de Nh OF OL Chahta pede de 91 34 49 62 TKGATIVAS 25 4 5 0 Di ey he ear eb tk K 92 G4 A963 DIC aie eae els MEA RRA Aa a BPE A 92 SLAG G4 UDIP 5446 40464448 8 Fee Ee a eee ead ee a 93 34 49 05 Unixplot za ol ete N A Aalto te he ote OE 2D 93 BAAD OO VEIA Sd ducts ty odena Ai Ale ehh ths ae Wha Sah tes a bf Zoe Gas actin ato 93 SAAD IGEN WS 8 AAA A A lt Me AE Na Rha Rs Ge aide Pact ha 93 34 49 68 Windows 3 6 ee ae SEPA LER EERE EAA eee Rhee See 93 34 49 68 1 Graph menma 0 a eee ee 94 34491682 Printings 6 0 2 eect a eae eas 94 34 49 68 3 Text Menu s sox a dei kw a SO we O
154. mand line Braces are used in text to be specially processed by some terminals like postscript They are also used to denote complex numbers 3 2 3 2i Text may be enclosed in single or double quotes Backslash processing of sequences like n newline and 345 octal character code is performed for double quoted strings but not for single quoted strings The justification is the same for each line of a multi line string Thus the center justified string This is the first line of text nThis is the second line will produce This is the first line of text This is the second line but This is the first line of text nThis is the second line will produce This is the first line of text nThis is the second line Filenames may be entered with either single or double quotes In this manual the command examples generally single quote filenames and double quote other string tokens for clarity At present you should not embed n inside when using the enhanced option of the postscript terminal The EEPIC Imagen Uniplex LaTeX and TPIC drivers allow a newline to be specified by in a single quoted string or in a double quoted string Back quotes are used to enclose system commands for substitution 14 16 Time Date data gnuplot supports the use of time and or date information as input data This feature is activated by the commands set xdata time set ydata time etc Internally all times and dates are co
155. mples This places the key at the default location set key This disables the key set nokey This places a key at coordinates 2 3 5 2 in the default first coordinate system 53 set key 2 3 5 2 This places the key below the graph set key below This places the key in the bottom left corner left justifies the text gives it a title and draws a box around it in linetype 3 set key left bottom Left title Legend box 3 34 23 Label Arbitrary labels can be placed on the plot using the set label command Syntax set label lt tag gt lt label_text gt fat lt position gt lt justification gt no rotate font lt name gt lt size gt set nolabel lt tag gt show label The lt position gt is specified by either x y or x y z and may be preceded by first second graph or screen to select the coordinate system See coordinates for details The tag is an integer that is used to identify the label If no lt tag gt is given the lowest unused tag value is assigned automatically The tag can be used to delete or modify a specific label To change any attribute of an existing label use the set label command with the appropriate tag and specify the parts of the label to be changed By default the text is placed flush left against the point x y z To adjust the way the label is positioned with respect to the point x y z add the parameter lt justification gt which may be left right or center indica
156. n Fortran and C As in those languages parentheses may be used to change the order of operation Thus 2 2 4 but 2 2 4 The factorial operator returns a real number to allow a greater range 10 2 2 Binary The following is a list of all the binary operators and their usages 10 Binary Operators Symbol Example Explanation x ax x b exponentiation axb multiplication a b division ab modulo atb addition a b subtraction a equality I a b inequality a lt b less than lt a lt b less than or equal to gt a gt b greater than gt a gt b greater than or equal to amp agb bitwise AND E ab bitwise exclusive OR alb bitwise inclusive OR amp amp ak amp b logical AND allb logical OR Starred explanations indicate that the operator requires integer arguments Logical AND amp amp and OR short circuit the way they do in C That is the second amp amp operand is not evaluated if the first is false the second operand is not evaluated if the first is true 10 2 3 Ternary There is a single ternary operator Ternary Operator Symbol Example Explanation a bic ternary operation The ternary operator behaves as it does in C The first argument a which must be an integer is evaluated If it is true non zero the second argument b is evaluated and returned otherwise the third argument c is evaluated and returned The
157. n colour MIF sep 2 7 and monochrome plots all line types in black MIF sep 0 polyline plots curves as continuous curves and vectors plots curves as collections of vectors help and print online help on standard error output both print a short description of the usage help also lists the options Examples set term mif colour polylines defaults set term mif defaults set term mif vectors set term mif help 85 34 49 43 Mtos The mtos terminal has no options It sends data via a pipe to an external program called GPCLIENT It runs under MULTITOS Magic 3 x MagicMAC and MiNT If you cannot find GPCLIENT than mail to dirk lstm uni erlangen de 34 49 44 Next Several options may be set in the next driver Syntax set terminal next lt mode gt lt type gt lt color gt lt dashed gt lt fontname gt lt fontsize gt title lt newtitle gt where lt mode gt is default which sets all options to their defaults lt type gt is either new or old where old invokes the old single window lt color gt is either color or monochrome lt dashed gt is either solid or dashed lt fontname gt is the name of a valid PostScript font lt fontsize gt is the size of the font in PostScript points and lt title gt is the title for the GnuTerm window Defaults are new monochrome dashed Helvetica 14pt Examples set term next default set term next 22 set term next color Times Roman 14 set term
158. nd changes tics on the y2 right hand axis to months of the year Please see set xmtics for details 108 34 81 Y2range The set y2range command sets the vertical range that will be displayed on the y2 right hand axis Please see set xrange for details 34 82 Y2tics The set y2tics command controls major labelled tics on the y2 right hand axis Please see set xtics for details 34 83 Y2zeroaxis The set y2zeroaxis command draws a line at the origin of the y2 right hand axis x2 0 For details please see set zeroaxis 34 84 Ydata Sets y axis data to timeseries dates times Please see set xdata 34 85 Ydtics The set ydtics command changes tics on the y axis to days of the week Please see set xdtics for details 34 86 Ylabel This command sets the label for the y axis Please see set xlabel 34 87 Ymtics The set ymtics command changes tics on the y axis to months of the year Please see set xmtics for details 34 88 Yrange The set yrange command sets the vertical range that will be displayed on the y axis Please see set xrange for details 34 89 Ytics The set ytics command controls major labelled tics on the y axis Please see set xtics for details 34 90 Yzeroaxis The set yzeroaxis command draws a line at x 0 For details please see set zeroaxis 34 91 Zdata Set zaxis date to timeseries dates times Please see set xdata 109 34 92 Zdtics The set zdtics command changes tics on
159. nd left Ranges specified on the plot command apply only to the first set of axes bottom left Examples plot sin x plot f x sin x a a 2 f x a 4 f x 25 plot t 1 10 pi pi 2 tan t data 1 using tan 2 3 4 smooth csplines axes xly2 notitle with lines 5 26 1 Data file Discrete data contained in a file can be displayed by specifying the name of the data file enclosed in single or double quotes on the plot command line Syntax plot lt file_name gt index lt index list gt every lt every list gt thru lt thru expression gt using lt using list gt smooth lt option gt The modifiers index every thru using and smooth are discussed separately In brief index selects which data sets in a multi data set file are to be plotted every specifies which points within a single data set are to be plotted using determines how the columns within a single record are to be interpreted thru is a special case of using and smooth allows for simple interpolation and approximation splot has a similar syntax but does not support the smooth and thru options Data files should contain at least one data point per record using can select one data point from the record Records beginning with and also with on VMS will be treated as comments and ignored Each data point represents an x y pair For plots with error bars see set style errorbars each data point is x y ydelta x
160. next color Helvetica 12 title MyPlot set term next old Pointsizes may be changed with set linestyle 34 49 45 Next Several options may be set in the next driver Syntax set terminal next lt mode gt lt type gt lt color gt lt dashed gt lt fontname gt lt fontsize gt title lt newtitle gt where lt mode gt is default which sets all options to their defaults lt type gt is either new or old where old invokes the old single window lt color gt is either color or monochrome lt dashed gt is either solid or dashed lt fontname gt is the name of a valid PostScript font lt fontsize gt is the size of the font in PostScript points and lt title gt is the title for the GnuTerm window Defaults are new monochrome dashed Helvetica 14pt Examples set term next default set term next 22 set term next color Times Roman 14 set term next color Helvetica 12 title MyPlot set term next old Pointsizes may be changed with set linestyle 34 49 46 Pbm Several options may be set in the pbm terminal the driver for PBMplus Syntax 86 set terminal pbm lt fontsize gt lt mode gt where lt fontsize gt is small medium or large and lt mode gt is monochrome gray or color The default plot size is 640 pixels wide and 480 pixels high this may be changed by set size The output of the pbm driver depends upon lt mode gt monochrome produces a portable bitmap one bit p
161. ng slowly as the parameters are varied or it may reach a numerically unstable region e g too large a number causing a floating point overflow which results in an undefined value message or gnuplot halting 22 To improve the chances of finding the global optimum you should set the starting values at least roughly in the vicinity of the solution e g within an order of magnitude if possible The closer your starting values are to the solution the less chance of stopping at another minimum One way to find starting values is to plot data and the fitting function on the same graph and change parameter values and replot until reasonable similarity is reached The same plot is also useful to check whether the fit stopped at a minimum with a poor fit Of course a reasonably good fit is not proof there is not a better fit in either a statistical sense characterized by an improved goodness of fit criterion or a physical sense with a solution more consistent with the model Depending on the problem it may be desirable to fit with various sets of starting values covering a reasonable range for each parameter 21 7 Tips Here are some tips to keep in mind to get the most out of fit They re not very organized so you ll have to read them several times until their essence has sunk in The two forms of the via argument to fit serve two largely distinct purposes The via file form is best used for possibly unattended batch operation
162. nverted to the number of seconds from the year 2000 The command set timefmt defines the format for all inputs data files ranges tics label positions in short anything that accepts a data value must receive it in this format Since only one input format can be in force at a given time all time date quantities being input at the same time must be presented in the same format Thus if both x and y data in a file are time date they must be in the same format The conversion to and from seconds assumes Universal Time which is the same as Greenwich Standard Time There is no provision for changing the time zone or for daylight savings If all your data refer to the same time zone and are all either daylight or standard you don t need to worry about these things But if the absolute time is crucial for your application you ll need to convert to UT yourself Commands like show xrange will re interpret the integer according to timefmt If you change timefmt and then show the quantity again it will be displayed in the new timefmt For that matter if you give the deactivation command like set xdata the quantity will be shown in its numerical form The command set format defines the format that will be used for tic labels whether or not the specified axis is time date If time date information is to be plotted from a file the using option must be used on the plot or splot command These commands simply use white space to separate columns but w
163. o m ztics no m x2tics no m y2tics polar lt angle gt linestyle lt major_linestyle gt linetype 1t lt major_linetype gt linewidth lw lt major_linewidth gt linestyle ls lt minor_linestyle gt linetype 1t lt minor_linetype gt linewidth lw lt minor_linewidth gt set nogrid show grid The grid can be enabled and disabled for the major and or minor tic marks on any axis and the linetype and linewidth can be specified for major and minor grid lines also via a predefined linestyle as far as the active terminal driver supports this Additionally a polar grid can be selected for 2 d plots circles are drawn to intersect the selected tics and radial lines are drawn at definable intervals The interval is given in degrees or radians depending on the set angles setting Note that a polar grid is no longer automatically generated in polar mode The pertinent tics must be enabled before set grid can draw them gnuplot will quietly ignore instruc tions to draw grid lines at non existent tics but they will appear if the tics are subsequently enabled If no linetype is specified for the minor gridlines the same linetype as the major gridlines is used The default polar angle is 30 degrees By default grid lines are drawn with half the usual linewidth The major and minor linewidth specifiers scale this default value for example set grid lw 5 will draw grid lines with one quarter the usu
164. o a different device A plot window can be closed by pressing the letter q while that window has input focus or by choosing close from a window manager menu All plot windows can be closed by specifying reset which actually terminates the subprocess which maintains the windows unless persist was specified Plot windows will automatically be closed at the end of the session unless the persist option was given The size or aspect ratio of a plot may be changed by resizing the gnuplot window Linewidths and pointsizes may be changed from within gnuplot with set linestyle For terminal type be gnuplot accepts when initialized the standard X Toolkit options and resources such as geometry font and name from the command line arguments or a configuration file See the X 1 man page or its equivalent for a description of such options A number of other gnuplot options are available for the be terminal These may be specified either as command line options when gnuplot is invoked or as resources in the configuration file Xdefaults They are set upon initialization and cannot be altered during a gnuplot session 34 49 7 1 Command line_options In addition to the X Toolkit options the following options may be specified on the command line when starting gnuplot or as resources in your Xdefaults file mono forces monochrome rendering on color displays gray requests grayscale rendering on grayscale or color displays Grayscale displ
165. o allow for the debugging of gnuplot It is likely to be of use only for users who are modifying the source code 34 49 12 Svga The svga terminal driver supports PCs with SVGA graphics It can only be be used if it is compiled with DJGPP Its only option is the font Syntax set terminal svga lt fontname gt 34 49 13 Dumb The dumb terminal driver has an optional size specification and trailing linefeed control Syntax set terminal dumb no feed lt xsize gt lt ysize gt where lt xsize gt and lt ysize gt set the size of the dumb terminals Default is 79 by 24 The last newline is printed only if feed is enabled Examples set term dumb nofeed set term dumb 79 49 VGA screen why would anyone do that 73 34 49 14 Dxf The dxf terminal driver creates pictures that can be imported into AutoCad Release 10 x It has no options of its own but some features of its plots may be modified by other means The default size is 120x80 AutoCad units which can be changed by set size dxf uses seven colors white red yellow green cyan blue and magenta which can be changed only by modifying the source file If a black and white plotting device is used the colors are mapped to differing line thicknesses See the description of the AutoCad print plot command 34 49 15 Dxy800a This terminal driver supports the Roland DXY800A plotter It has no options 34 49 16 Eepic The eepic terminal driver supports the extend
166. o describe in words try them set xlabel Time 10 6 Symbol m s set title Symbol 18 362 _ 9 6 0 12 x Helvetica e Symbol m 2 2 d Symbol my The file ps_guide ps in the docs ps subdirectory of the gnuplot source distribution contains more examples of the enhanced syntax 34 49 50 2 Editing postscript The PostScript language is a very complex language far too complex to describe in any detail in this document Nevertheless there are some things in a PostScript file written by gnuplot that can be changed without risk of introducing fatal errors into the file For example the PostScript statement Color true def written into the file in response to the command set terminal postscript color may be altered in an obvious way to generate a black and white version of a plot Similarly line colors text colors line weights and symbol sizes can also be altered in straight forward ways Text titles and labels can be edited to correct misspellings or to change fonts Anything can be repositioned and of course anything can be added or deleted but modifications such as these may require deeper knowledge of the PostScript language The organization of a PostScript file written by gnuplot is discussed in the text file ps_file doc in the docs ps subdirectory 34 49 51 Pslatex and pstex The pslatex and pstex drivers generate output for further processing by LaTeX and TeX respectively Figures gener
167. ompiled with Borland C uses the Turbo C graphics drivers and does work correctly with VGA displays VAX VMS 4 7 C compiler release 2 4 also has a poorly implemented g format for printf The numbers are printed numerically correct but may not be in the requested format The K amp R second edition says that for the g format e is used if the exponent is less than 4 or greater than or equal to the precision The VAX uses e format if the exponent is less than 1 The VAX appears to take no notice of the precision when deciding whether to use e or f for numbers less than 1 To work around this problem use the e or f formats explicitly From the VAX C 2 4 release notes e E f F g G Result will always contain a decimal point For g and G trailing zeros will not be removed from the result VAX VMS 5 2 C compiler release 3 0 has a slightly better implemented g format than release 2 4 but not much Trailing decimal points are now removed but trailing zeros are still not removed from g numbers in exponential format The two preceding problems are actually in the libraries rather than in the compilers Thus the problems will occur whether gnuplot is built using either the DEC compiler or some other one e g the latest gcc ULTRIX X11R3 has a bug that causes the X11 driver to display every other graph The bug seems to be fixed in DEC s release of X11R4 so newer releases of ULTRIX don t seem to have the problem Solutions for older s
168. on e g a positive bottom offset makes ymin more negative Negative offsets while permitted can have unexpected interactions with autoscaling and clipping Offsets are ignored in splots Example set offsets 0 0 2 2 plot sin x This graph of sin x will have a y range 3 3 because the function will be autoscaled to 1 1 and the vertical offsets are each two 34 38 Origin The set origin command is used to specify the origin of a plotting surface i e the graph and its margins on the screen The coordinates are given in the screen coordinate system see coordinates for information about this system 59 Syntax set origin lt x origin gt lt y origin gt 34 39 Output By default screens are displayed to the standard output The set output command redirects the display to the specified file or device Syntax set output lt filename gt show output The filename must be enclosed in quotes If the filename is omitted any output file opened by a previous invocation of set output will be closed and new output will be sent to STDOUT If you give the command set output STDOUT your output may be sent to a file named STDOUT May be not will be because some terminals like x11 ignore set output MSDOS users should note that the character has special significance in double quoted strings so single quotes should be used for filenames in different directories When both set terminal and set output
169. on includes a font table In the picture body a font is designated by an index into this table By default this terminal generates a table with the following fonts 71 CGM fonts Arial Arial Italic Arial Bold Arial Bold Italic Times Roman Times Roman Italic Times Roman Bold Times Roman Bold Italic Helvetica Roman Case is not distinct but the modifiers must appear in the above order that is not Arial Italic Bold Arial Bold is the default font You may also specify a font name which does not appear in the default font table In that case a new font table is constructed with the specified font as its only entry You must ensure that the spelling capitalization and spacing of the name are appropriate for the application that will read the CGM file 34 49 9 2 Fontsize Fonts are scaled assuming the page is 6 inches wide If the size command is used to change the aspect ratio of the page or the CGM file is converted to a different width e g it is imported into a document in which the margins are not 6 inches apart the resulting font sizes will be different To change the assumed width use the width option 34 49 9 3 Linewidth The linewidth option sets the width of lines in pt The default width is 1 pt Scaling is affected by the actual width of the page as discussed under the fontsize and width options 34 49 9 4 Rotate The norotate option may be used to disable text rotation For example the CGM input f
170. on the size of mathematics and there is no foolproof way to make such a change except by globally setting a magnification factor This is the purpose of the magnification option It must be followed by a scaling factor All text NOT the graphs will be scaled by this factor Use this if you have math that you want at some size other than the default 10pt Unfortunately all math will be the same size but see the discussion below on editing the MP output mag will also work under notex but there seems no point in using it as the font size option below works as well A name in quotes selects the font that will be used when no explicit font is given in a set label or set title A name recognized by TeX a TFM file exists must be used The default is cmr10 unless notex is selected then it is pcrr8r Courier Even under notex a TFM file is needed by Metapost The file pcrr8r tfm is the name given to Courier in LaTeX s psnfss package If you change the font from the notex default choose a font that matches the ASCII encoding at least in the range 32 126 cmtt10 almost works but it has a nonblank character in position 32 space The size can be any number between 5 0 and 99 99 If it is omitted 10 0 is used It is advisable to use magstep sizes 10 times an integer or half integer power of 1 2 rounded to two decimals because those are the most available sizes of fonts in TeX systems All the options are optional If font information is giv
171. ont size to the initialisation file WGNUPLOT INI MENU BAR If the menu file WGNUPLOT MNU is found in the same directory as WGNUPLOT EXE then the menu specified in WGNUPLOT MNU will be loaded Menu commands Menu starts a new menu with the name on the following line EndMenu ends the current menu inserts a horizontal menu separator inserts a vertical menu separator Button puts the next macro on a push button instead of a menu Macros take two lines with the macro name menu entry on the first line and the macro on the second 95 line Leading spaces are ignored Macro commands INPUT Input string with prompt terminated by EOS or ENTER EOS End Of String terminator Generates no output OPEN Get name of file to open from list box with title of list box terminated by EOS followed by default filename terminated by EOS or ENTER This uses COMMDLG DLL from Windows 3 1 SAVE Get name of file to save Similar to OPEN Macro character substitutions ENTER Carriage Return Ar TAB Tab 011 ESC Escape 033 7A 001 Ey ABr Macros are limited to 256 characters after expansion 34 49 68 4 Wenuplot ini Windows gnuplot will read some of its options from the WGNU PLOT section of WGNUPLOT INI in the Windows directory A sample WGNUPLOT INI file WGNUPLOT TextOrigin 0 0 TextSize 640 150 TextFont Terminal 9 GraphOrigin 0 150 GraphS
172. ontsize gt where lt x y gt specifies the number of graphs in the x and y directions on the page lt fontname gt is the name of a valid PostScript font and lt fontsize gt specifies the size of the PostScript font Defaults are portrait 1 1 dashed Helvetica and 18 The solid option is usually prefered if lines are colored as they often are in the editor Hardcopy will be black and white so dashed should be chosen for that Multiplot is implemented in two different ways The first multiplot implementation is the standard gnuplot multiplot feature set terminal tgif set output file obj set multiplot set origin x01 y01 set size xs ys plot set origin x02 y02 plot set nomultiplot See set multiplot for further information The second version is the x y option for the driver itself The advantage of this implementation is that everything is scaled and placed automatically without the need for setting origins and sizes the graphs keep their natural x y proportions of 3 2 or whatever is fixed by set size If both multiplot methods are selected the standard method is chosen and a warning message is given Examples of single plots or standard multiplot set terminal tgif defaults set terminal tgif Times Roman 24 set terminal tgif landscape set terminal tgif landscape solid Examples using the built in multiplot mechanism set terminal tgif portrait 2 4 portrait 2 plots in the x and 4 in t
173. ooa 2 00000 ee eee 68 34 49 7 2 Monochome options ooa e ee ee 68 34 49 7 3 Color_resources aa A E E E E e ee 68 34 49 7 4 Grayscale_resources ooo 69 34 49 75 Linesresourees s snede uee e Pe AMAA A a 69 3449 8 OU anere y a Ban E AA a aa a BED oe 70 34499 COM wis ee db eAeeeh SRE REDDER YEAS Dace ard ad a A wee 70 31 49 91 BOI tears a da Be AM Bee de a Ae A ls he a BO A 70 34 49 92 BOM SIZO amp baaa A a pelea tad O Bick S a A 71 SALADOS Dinewidth cdi AA tt E E AS 71 34 49 9 4 Rotate aaa e A a Bde e eee RA e 71 94 49 9 5 Solid 524250 40428 e ode eb ine Ghee S268 8 aah aa 71 94 49 9 6 SIZE a SA eee Ee ee a eee de eye eee eg at al hah a 71 SALADA A Width ra ee SiN eee AAA OO Ge EEE EDs 71 34 49 9 8 Winword6 0 00 a aa a ee 72 34 49 10 Corel oie in eo ES RAO he ee Ad 72 34 49 LID Dug a0 Yh PRO BE PASS Wee ae BE ata eae S 72 G4 AQ 2 SV EA od edb be a de de eg alee E E ee ee ok Oki oe eo Band 72 SAA AS Dumb ede 2 of ata MEME RRA RS AAA AEE Ee A 72 SLANIA DKE Bi oesdadadaed eed e bee gb eas a dt a od hes 73 3449 15 x7 800A Ciara a A ds Te Bo A Sd 73 S4 A910 epics Bisa w ob ded tenn eal dd A es Se ahh a ee ER a a RA 73 VARICES i oo boo eee es Se eee a A et Se A 73 34 49 18 Epsons18S0dPi sa La SER eee PEAS Seas te ee ARSE EHH 74 S4 A919 IAN 74 34 49 20 Hercules oo 2 e48e ee bbb hee eee bd dpe ee See eee S 74 SA 49 21 PIG om Oe PRO A INS AA A a el DA Be 74 34 49 22 Gifs io A d
174. order tells gnuplot to put the tics both the tics themselves and the accompanying labels along the axis or the border respectively If the axis is very close to the border the axis option can result in tic labels overwriting other text written in the margin mirror tells gnuplot to put unlabelled tics at the same positions on the opposite border nomirror does what you think it does rotate asks gnuplot to rotate the text through 90 degrees which will be done if the terminal driver in use supports text rotation norotate cancels this The defaults are border mirror norotate for tics on the x and y axes and border nomirror norotate for tics on the x2 and y2 axes For the z axis the the axis border option is not available and the default is nomirror If you do want to mirror the z axis tics you might want to create a bit more room for them with set border set xtics with no options restores the default border or axis if xtics are being displayed otherwise it has no effect Any previously specified tic frequency or position and labels are retained Positions of the tics are calculated automatically by default or if the autofreq option is given otherwise they may be specified in either of two forms The implicit lt start gt lt incr gt lt end gt form specifies that a series of tics will be plotted on the axis between the values lt start gt and lt end gt with an increment of lt incr gt If lt end gt is not given it is ass
175. points separated by a blank record If all datablocks contain the same number of points gnuplot will draw cross isolines between datablocks connecting corresponding points This is termed grid data and is required for drawing a surface for contouring set contour and hidden line removal set hidden3d See also splot grid data It is no longer necessary to specify parametric mode for three column splots 36 1 1 Binary splot can read binary files written with a specific format and on a system with a compatible binary file representation In previous versions gnuplot dynamically detected binary data files It is now necessary to specify the keyword binary directly after the filename Single precision floats are stored in a binary file as follows lt N 1 gt lt y0 gt lt y1 gt lt y2 gt lt yN gt lt x0 gt lt z0 0 gt lt z0 1 gt lt z0 2 gt lt z0 N gt lt x1 gt lt z1 0 gt lt z1 1 gt lt z1 2 gt lt z1 N gt which are converted into triplets lt x0 gt lt y0 gt lt z0 0 gt lt x0 gt lt y1 gt lt z0 1 gt lt x0 gt lt y2 gt lt z0 2 gt lt x0 gt lt yN gt lt z0 N gt lt x1 gt lt y0 gt lt z1 0 gt lt x1 gt lt y1 gt lt z1 1 gt These triplets are then converted into gnuplot iso curves and then gnuplot proceeds in the usual manner to do the rest of the plotting A collection of matrix and vector manipulation routines in C is provided in binary c The routine to write bin
176. provided you 1 distribute the corresponding source modifications from the released version in the form of a patch file along with the binaries 2 add special version identification to distinguish your version in addition to the base release version number 3 provide your name and address as the primary contact for the support of your modified version and 4 retain our contact information in regard to use of the base software Permission to distribute the released version of the source code along with corresponding source modifi cations in the form of a patch file is granted with same provisions 2 through 4 for binary distributions This software is provided as is without express or implied warranty to the extent permitted by ap plicable law AUTHORS Original Software Thomas Williams Colin Kelley Gnuplot 2 0 additions Russell Lang Dave Kotz John Campbell Gnuplot 3 0 additions Gershon Elber and many others 2 Introduction gnuplot is a command driven interactive function and data plotting program It is case sensitive commands and function names written in lowercase are not the same as those written in CAPS All command names may be abbreviated as long as the abbreviation is not ambiguous Any number of commands may appear on a line with the exception that load or call must be the final command separated by semicolons Strings are indicated with quotes They may be either single or double quotation marks e g
177. ps or default solid draws all plots with solid lines overriding any dashed patterns lt duplexing gt is defaultplex simplex or duplex duplexing in PostScript is the ability of the printer to print on both sides of the same page don t set this if your printer can t do it enhanced activates the enhanced PostScript features subscripts superscripts and mixed fonts lt fontname gt is the name of a valid PostScript font and lt fontsize gt is the size of the font in PostScript points default mode sets all options to their defaults landscape monochrome dashed defaultplex noenhanced Helvetica and 14pt Default size of a PostScript plot is 10 inches wide and 7 inches high eps mode generates EPS Encapsulated PostScript output which is just regular PostScript with some additional lines that allow the file to be imported into a variety of other applications The added lines are PostScript comment lines so the file may still be printed by itself To get EPS output use the eps mode and make only one plot per file In eps mode the whole plot including the fonts is reduced to half of the default size Examples set terminal postscript default old postscript set terminal postscript enhanced old enhpost set terminal postscript landscape 22 old psbig set terminal postscript eps 14 old epsf1 set terminal postscript eps 22 old epsf2 set size 0 7 1 4 set term post portrait color Times Roman 14 Linewidths
178. r the Talaris 1200 and others It has no options 90 34 49 54 Regis The regis terminal device generates output in the REGIS graphics language It has the option of using 4 the default or 16 colors Syntax set terminal regis 4 16 34 49 55 Rgip The rgip and uniplex terminal drivers support RGIP metafiles They can combine several graphs on a single page but only one page is allowed in a given output file Syntax set terminal rgip uniplex portrait landscape lt horiz gt lt vert gt lt fontsize gt permissible values for the font size are in the range 1 8 with the default being 1 The default layout is landscape Graphs are placed on the page in a horizxvert grid which defaults to 1 1 Example set terminal uniplex portrait 2 3 puts six graphs on a page in three rows of two in portrait orientation 34 49 56 Sun The sun terminal driver supports the SunView window system It has no options 34 49 57 Tek410x The tek410x terminal driver supports the 410x and 420x family of Tektronix terminals It has no options 34 49 58 Table Instead of producing a graph the table terminal prints out the points on which a graph would be based i e the results of processing the plot or splot command in a multicolumn ASCII table of X Y Z R values The character R takes on one of three values i if the point is in the active range o if it is out of range or u if it is undefined The data format is de
179. r system hexadecimal RGB color specifications see BE documentation or a color name followed by a comma and an intensity value from 0 to 1 For example blue 0 5 means a half intensity blue 69 gnuplot background white gnuplot textColor black gnuplot borderColor black gnuplot axisColor black gnuplot linelColor red gnuplot line2Color green gnuplot line3Color blue gnuplot line4Color magenta gnuplot line5Color cyan gnuplot line6Color sienna gnuplot line7Color orange gnuplot line8Color coral The command line syntax for these is for example Example gnuplot background coral 34 49 7 4 Grayscale_ resources When gray is selected gnuplot honors the following resources for grayscale or color displays shown here with their default values Note that the default background is black gnuplot background black gnuplot textGray white gnuplot borderGray gray50 gnuplot axisGray gray50 gnuplot linelGray gray100 gnuplot line2Gray gray60 gnuplot line3Gray gray80 gnuplot line4Gray gray40 enuplot line5Gray gray90 gnuplot line6Gray gray50 gnuplot line7Gray gray70 egnuplot lineSGray gray30 34 49 7 5 Line resources gnuplot honors the following resources for setting the width in pixels of plot lines shown here with their default values 0 or 1 means a minimal width line of 1 pixel width A value of 2 or 3 may improve the appearance of some plots gnuplot borderWidth 2
180. rent directory the program will look for it in the home directory under AmigaOS Atari single TOS MS DOS and OS 2 the environment variable gnuplot should contain the name of this directory Note if NOCWDRC is defined during the installation gnuplot will not read from the current directory If the initialization file is found gnuplot executes the commands in it These may be any legal gnuplot commands but typically they are limited to setting the terminal and defining frequently used functions or variables 14 Substitution Command line substitution is specified by a system command enclosed in backquotes This command is spawned and the output it produces replaces the name of the command and backquotes on the command line Some implementations also support pipes see plot data file special filenames Newlines in the output produced by the spawned command are replaced with blanks Command line substitution can be used anywhere on the gnuplot command line Example This will run the program leastsq and replace leastsq including backquotes on the command line with its output 13 f x leastsq or in VMS f x run leastsq 15 Syntax The general rules of syntax and punctuation in gnuplot are that keywords and options are order dependent Options and any accompanying parameters are separated by spaces whereas lists and coor dinates are separated by commas Ranges are separated by colons and enclosed in brackets tex
181. ring must exclude this text But it can still be printed with the a A b or B specifier see set format for more details about these and other options for printing timedata gnuplot will determine the proper month and weekday from the numerical values See also set xdata and Time date for more information Example set timefmt d m 4YWt H 7 M tells gnuplot to read date and time separated by tab But look closely at your data what began as a tab may have been converted to spaces somewhere along the line the format string must match what is actually in the file 34 55 Title The set title command produces a plot title that is centered at the top of the plot set title is a special case of set label Syntax set title lt title text gt lt xoff gt lt yoff gt lt font gt lt size gt show title Specifying constants lt xoff gt or lt yoff gt as optional offsets for the title will move the title lt xoff gt or lt yoff gt character screen coordinates not graph coordinates For example set title 1 will change only the y offset of the title moving the title down by roughly the height of one character lt font gt is used to specify the font with which the title is to be written the units of the font lt size gt depend upon which terminal is used set title with no parameters clears the title 101 See syntax for details about the processing of backslash sequences and the distinction
182. rom consecutive records delimited by blank records A line when referred to in the context of a data file is a subset of a datablock 12 Plotting There are three gnuplot commands which actually create a plot plot splot and replot plot gen erates 2 d plots splot generates 3 d plots actually 2 d projections of course and replot appends its arguments to the previous plot or splot and executes the modified command Much of the general information about plotting can be found in the discussion of plot information specific to 3 d can be found in the splot section plot operates in either rectangular or polar coordinates see set polar for details of the latter splot operates only in rectangular coordinates but the set mapping command allows for a few other coor dinate systems to be treated In addition the using option allows both plot and splot to treat almost any coordinate system you d care to define splot can plot surfaces and contours in addition to points and or lines In addition to splot see set isosamples for information about defining the grid for a 3 d function splot datafile for informa tion about the requisite file structure for 3 d data values and set contour and set cntrparam for information about contours 13 Start up When gnuplot is run it looks for an initialization file to load This file is called gnuplot on Unix and AmigaOS systems and GNUPLOT INI on other systems If this file is not found in the cur
183. rresponding point in the next y isoline Thus a splot contour of a surface with samples on the x isolines that do not coincide with a y isoline intersection will ignore such samples Try set xrange pi 2 pi 2 set yrange pi 2 pi 2 set function style lp set contour set isosamples 10 10 set samples 10 10 splot cos x cos y set samples 4 10 replot set samples 10 4 replot 36 3 Splot_overview splot can display a surface as a collection of points or by connecting those points As with plot the points may be read from a data file or result from evaluation of a function at specified intervals see set isosamples The surface may be approximated by connecting the points with straight line segments see set surface in which case the surface can be made opaque with set hidden3d The orientation from which the 3d surface is viewed can be changed with set view Additionally for points in a grid format splot can interpolate points having a common amplitude see set contour and can then connect those new points to display contour lines either directly with straight line segments or smoothed lines see set cntrparams Functions are already evaluated in a grid format determined by set isosamples and set samples while file data must either be in a grid format as described in data file or be used to generate a grid see set dgrid3d Contour lines may be displayed either on the surface or projected onto the base The base projections o
184. rs If the format string is omitted the format will be returned to the default g For LaTeX users the format e is often desirable If the empty string is used no label will be plotted with each tic though the tic mark will still be plotted To eliminate all tic marks use set noxtics or set noytics Newline n is accepted in the format string Use double quotes rather than single quotes to enable such interpretation See also syntax The default format for both axes is g but other formats such as 2f or 3 0em are often desirable Anything accepted by printf when given a double precision number and accepted by the terminal will work Some other options have been added If the format string looks like a floating point format then gnuplot tries to construct a reasonable format Characters not preceded by are printed verbatim Thus you can include spaces and labels in your format string such as g m which will put m after each number If you want itself double it g See also set xtics for more information about tic labels 34 16 1 Format specifiers The acceptable formats if not in time date mode are Tic mark label numerical format specifiers Format Explanation hf floating point notation e or 4E exponential notation an e or E before the power g or G the shorter of e or E and f x or 4X hex ho or 40 octal ht mantissa to base 10 Al mantissa to base of
185. s an output filter for help messages On Unix AtariTOS and AmigaOS SHELL is used for the shell command On MS DOS and OS 2 COMSPEC is used for the shell command On MS DOS if the BGI or Watcom interface is used PCTRM is used to tell the maximum resolution supported by your monitor by setting it to S lt max horizontal resolution gt E g if your monitor s maximum resolution is 800x600 then use set PCTRM S800 If PCTRM is not set standard VGA is used FIT_SCRIPT may be used to specify a gnuplot command to be executed when a fit is interrupted see fit FIT_LOG specifies the filename of the logfile maintained by fit 10 Expressions In general any mathematical expression accepted by C FORTRAN Pascal or BASIC is valid The precedence of these operators is determined by the specifications of the C programming language White space spaces and tabs is ignored inside expressions Complex constants are expressed as lt real gt lt imag gt where lt real gt and lt imag gt must be numerical constants For example 3 2 represents 3 2i 0 1 represents i itself The curly braces are explicitly required here Note that gnuplot uses both real and integer arithmetic like FORTRAN and C Integers are entered as 1 10 etc reals as 1 0 10 0 lel 3 5e 1 etc The most important difference between the two forms is in division division of integers truncates 5 2 2 division of reals does not 5 0 2
186. s being loaded may themselves contain load or call commands See comment for information about comments in commands To load with arguments see call The load command must be the last command on a multi command line Syntax load lt input file gt The name of the input file must be enclosed in quotes The special filename may be used to load commands from standard input This allows a gnuplot command file to accept some commands from standard input Please see help batch interactive for more details Examples 24 load work gnu load func dat The load command is performed implicitly on any file names given as arguments to gnuplot These are loaded in the order specified and then gnuplot exits 25 Pause The pause command displays any text associated with the command and then waits a specified amount of time or until the carriage return is pressed pause is especially useful in conjunction with load files Syntax pause lt time gt lt string gt lt time gt may be any integer constant or expression Choosing 1 will wait until a carriage return is hit zero 0 won t pause at all and a positive integer will wait the specified number of seconds pause 0 is synonymous with print Note Since pause communicates with the operating system rather than the graphics it may behave differently with different device drivers depending upon how text and graphics are mixed Examples pause 1 Wait until a carri
187. s may help for best positioning Examples set term pslatex monochrome dashed rotate set to defaults To write the PostScript commands into the file foo ps set term pslatex auxfile set output foo tex plot set output About label positioning Use gnuplot defaults mostly sensible but sometimes not really best set title LaTeX gamma Force centering both horizontally and vertically set label LaTeX gamma at 0 0 Specify own positioning top here set xlabel t LaTeX gamma The other label account for long ticlabels set ylabel r LaTeX gamma rule 7mm Opt Linewidths and pointsizes may be changed with set linestyle 34 49 52 Pstricks The pstricks driver is intended for use with the pstricks sty macro package for LaTeX It is an alternative to the eepic and latex drivers You need pstricks sty and of course a printer that understands PostScript or a converter such as Ghostscript PSTricks is available via anonymous ftp from the pub directory at Princeton EDU This driver definitely does not come close to using the full capability of the PSTricks package Syntax set terminal pstricks fhacktext nohacktext unit nounit The first option invokes an ugly hack that gives nicer numbers the second has to do with plot scaling The defaults are hacktext and nounit 34 49 53 Qms The qms terminal driver supports the QMS QUIC Laser printe
188. ses the data to determine the coefficients of a continuous curve between the endpoints of the data This curve is then plotted in the same manner as a function that is by finding its value at uniform intervals along the abscissa see set samples and connecting these points with straight line segments if a line style is chosen If autoscale is in effect the ranges will be computed such that the plotted curve lies within the borders of the graph If too few points are available to allow the selected option to be applied an error message is produced The minimum number is one for unique four for acsplines and three for the others The smooth options have no effect on function plots 26 1 4 1 Acsplines The acsplines option approximates the data with a natural smoothing spline After the data are made monotonic in x see smooth unique a curve is piecewise constructed from segments of cubic polynomials whose coefficients are found by the weighting the data points the weights are taken from the third column in the data file That default can be modified by the third entry in the using list e g plot data file using 1 2 1 0 smooth acsplines Qualitatively the absolute magnitude of the weights determines the number of segments used to construct the curve If the weights are large the effect of each datum is large and the curve approaches that produced by connecting consecutive points with natural cubic splines If the weights are
189. sets the default depth layer for all lines and text The default depth is 10 to leave room for adding material with xfig on top of the plot thickness sets the default line thickness which is 1 if not specified Overriding the thickness can be achieved by adding a multiple of 100 to the to the linetype value for a plot command In a similar way the depth of plot elements with respect to the default depth can be controlled by adding a multiple of 1000 to lt linetype gt The depth is then lt layer gt lt linetype gt 1000 and the thickness is lt linetype gt 1000 100 or if that is zero the default line thickness Additional point plot symbols are also available with the fig driver The symbols can be used through pointtype values 100 above 50 with different fill intensities controlled by lt pointtype gt 5 and outlines in black for lt pointtype gt 10 lt 5 or in the current color Available symbols are 50 59 circles 60 69 squares 70 79 diamonds 80 89 upwards triangles 90 99 downwards triangles The size of these symbols is linked to the font size The depth of symbols is by default one less than the depth for lines to achieve nice error bars If lt pointtype gt is above 1000 the depth is lt layer gt lt pointtype gt 1000 1 If lt pointtype gt 1000 is above 100 the fill color is lt pointtype gt 1000 100 1 Available fill colors are from 1 to 9 black blue green cyan red magenta yel
190. small the curve is composed of fewer segments and thus is smoother the limiting case is the single segment produced by a weighted linear least squares fit to all the data The smoothing weight can be expressed in terms of errors as a statistical weight for a point divided by a smoothing factor for the curve so that standard errors in the file can be used as smoothing weights Example sw x S 1 x x S plot data_file using 1 2 sw 3 100 smooth acsplines 26 1 4 2 Bezier The bezier option approximates the data with a Bezier curve of degree n the number of data points that connects the endpoints 26 1 4 3 Csplines The csplines option connects consecutive points by natural cubic splines after rendering the data monotonic see smooth unique 28 26 1 4 4 Sbezier The sbezier option first renders the data monotonic unique and then applies the bezier algorithm 26 1 4 5 Unique The unique option makes the data monotonic in x points with the same x value are replaced by a single point having the average y value The resulting points are then connected by straight line segments 26 1 5 Special filenames A special filename of specifies that the data are inline i e they follow the command Only the data follow the command plot options like filters titles and line styles remain on the plot command line This is similar to lt lt in unix shell script and DECK in VMS DCL The data are entered as though they are
191. specified on the plot or splot command or will be chosen sequentially from the types available to the terminal in use Use the command test to see what is available None of the styles requiring more than two columns of information e g errorbars can be used with splots or function plots Neither boxes nor any of the steps styles can be used with splots If an inappropriate style is specified it will be changed to points For 2 d data with more than two columns gnuplot is picky about the allowed errorbar styles The using option on the plot command can be used to set up the correct columns for the style you want In this discussion column will be used to refer both to a column in the data file and an entry in the using list For three columns only xerrorbars yerrorbars or errorbars boxes and boxerrorbars are al lowed If another plot style is used the style will be changed to yerrorbars The boxerrorbars style will calculate the boxwidth automatically For four columns only xerrorbars yerrorbars or errorbars xyerrorbars boxxyerrorbars and boxerrorbars are allowed An illegal style will be changed to yerrorbars Five column data allow only the boxerrorbars financebars and candlesticks styles The last two of these are primarily used for plots of financial prices An illegal style will be changed to boxerrorbars before plotting 63 Six and seven column data only allow the xyerrorbars and boxxyerrorbars styles Illega
192. ssian normal distribution about the mean with a given standard deviation For a sample of sufficiently large size and knowing the population standard deviation one can use the statistics of the chisquare distribution to describe a goodness of fit by looking at the variable often called chisquare Here it is sufficient to say that a reduced chisquare chisquare degrees of freedom where degrees of freedom is the number of datapoints less the number of parameters being fitted of 1 0 is an indication that the weighted sum of squared deviations between the fitted function and the data points is the same as that expected for a random sample from a population characterized by the function with the current value of the parameters and the given standard deviations If the standard deviation for the population is not constant as in counting statistics where variance counts then each point should be individually weighted when comparing the observed sum of deviations and the expected sum of deviations At the conclusion fit reports stdfit the standard deviation of the fit which is the rms of the residuals and the variance of the residuals also called reduced chisquare when the data points are weighted The number of degrees of freedom the number of data points minus the number of fitted parameters is used in these estimates because the parameters used in calculating the residuals of the datapoints were obtained from the same data To e
193. stimate confidence levels for the parameters one can use the minimum chisquare obtained from the fit and chisquare statistics to determine the value of chisquare corresponding to the desired confidence level but considerably more calculation is required to determine the combinations of parameters which produce such values Rather than determine confidence intervals fit reports parameter error estimates which are readily obtained from the variance covariance matrix after the final iteration By convention these estimates are called standard errors or asymptotic standard errors since they are calculated in the same way as the standard errors standard deviation of each parameter of a linear least squares problem even though the statistical conditions for designating the quantity calculated to be a standard deviation are not generally valid for the NLLS problem The asymptotic standard errors are generally over optimistic and should not be used for determining confidence levels but are useful for qualitative purposes The final solution also produces a correlation matrix which gives an indication of the correlation of pa rameters in the region of the solution if one parameter is changed increasing chisquare does changing another compensate The main diagonal elements autocorrelation are all 1 if all parameters were in dependent all other elements would be nearly 0 Two variables which completely compensate each other would have an off dia
194. t and file names are enclosed in quotes and a few miscellaneous things are enclosed in parentheses Braces are used for a few special purposes Commas are used to separate coordinates on the set commands arrow key and label the list of variables being fitted the list after the via keyword on the fit command lists of discrete contours or the loop parameters which specify them on the set cntrparam command the arguments of the set commands dgrid3d dummy isosamples offsets origin samples size time and view lists of tics or the loop parameters which specify them the offsets for titles and axis labels parametric functions to be used to calculate the x y and z coordinates on the plot replot and splot commands and the complete sets of keywords specifying individual plots data sets or functions on the plot replot and splot commands Parentheses are used to delimit sets of explicit tics as opposed to loop parameters and to indicate computations in the using filter of the fit plot replot and splot commands Parentheses and commas are also used as usual in function notation Brackets are used to delimit ranges whether they are given on set plot or splot commands Colons are used to separate extrema in range specifications whether they are given on set plot or splot commands and to separate entries in the using filter of the plot replot splot and fit commands Semicolons are used to separate commands given on a single com
195. t col15 The character size must appear if any colors are to be specified Each of the up to 16 colors is given as a three digit hex number where the digits represent RED GREEN and BLUE in that order The range of 0 15 is scaled to whatever color range the screen actually has On a normal ST screen odd and even intensities are the same Examples set terminal vdi 4 use small 6x6 font set terminal vdi 6 0 set monochrome screen to white on black set terminal vdi 13 0 fff f00 fO f ff fOf set first seven colors to black white green blue cyan purple and yellow and use large font 8x16 Additionally if an environment variable GNUCOLORS exists its contents are interpreted as an options string but an explicit terminal option takes precedence 34 49 7 Be gnuplot provides the be terminal type for use with X servers This terminal type is set automatically at startup if the DISPLAY environment variable is set if the TERM environment variable is set to xterm or if the display command line option is used Syntax set terminal be reset lt n gt 68 Multiple plot windows are supported set terminal be lt n gt directs the output to plot window number n If n gt 0 the terminal number will be appended to the window title and the icon will be labeled gplt lt n gt The active window may distinguished by a change in cursor from default to crosshair Plot windows remain open even when the gnuplot driver is changed t
196. tan2 y x int or real tan y x inverse tangent atanh x any tanh x inverse hyperbolic tangent in radians besj0 x int or real jo Bessel function of x in radians besj1 x int or real j Bessel function of x in radians besy0 x int or real y Bessel function of x in radians besy1 x int or real y Bessel function of x in radians ceil x any x smallest integer not less than x real part cos x any cos x cosine of x cosh x any cosh x hyperbolic cosine of x in radians erf x any erf real x error function of real x erfc x any erfc real x 1 0 error function of real z exp x any e exponential function of x floor x any x largest integer not greater than x real part gamma x any gamma real x gamma function of real x ibeta p q x any ibeta real p q 1 ibeta function of real p q u inverf x any inverse error function of real x igamma a x any igamma real a x igamma function of real a z imag x complex imaginary part of x as a real number invnorm x any inverse normal distribution function of real x int x real integer part of x truncated toward zero lgamma x any lgamma real x lgamma function of real x log x any log x natural logarithm base e of x log10 x any logy x logarithm base 10 of x norm x any normal distribution Gaussian function of real x rand x any rand real x pseudo random number generator real x any real part of x sgn x any lifx gt 0 1ifx lt 0 0ifx 0 imag x
197. tax set ticscale lt major gt lt minor gt show tics If lt minor gt is not specified it is 0 5 lt major gt The default size is 1 0 for major tics and 0 5 for minor tics Note that it is possible to have the tic marks pointing outward by specifying a negative size 34 53 Timestamp The command set timestamp places the time and date of the plot in the left margin Syntax set timestamp lt format gt top bottom no rotate lt xoff gt lt yoff gt lt font gt set notimestamp show timestamp The format string allows you to choose the format used to write the date and time Its default value is what asctime uses a b d H M S WY weekday month name day of the month hours minutes seconds four digit year With top or bottom you can place the timestamp at the top or bottom of the left margin default bottom rotate lets you write the timestamp vertically if your terminal supports vertical text The constants lt xoff gt and lt off gt are offsets from the default position given in character screen coordinates lt font gt is used to specify the font with which the time is to be written The abbreviation time may be used in place of timestamp Example set timestamp d m y H M 80 2 Helvetica See set timefmt for more information about time format strings 34 54 Timefmt This command applies to timeseries where data are composed of dates times It has no meaning unless the command set
198. termined by the format of the axis labels see set format For those times when you want the numbers you can display them on the screen or save them to a file This can be useful if you want to generate contours and then save them for further use perhaps for plotting with plot see set contour for an example The same method can be used to save interpolated data see set samples and set dgrid3d 34 49 59 Tek40 This family of terminal drivers supports a variety of VT like terminals tek40xx supports Tektronix 4010 and others as well as most TEK emulators vttek supports VT like tek40xx terminal emulators kc tek40xx supports MS DOS Kermit Tek4010 terminal emulators in color km tek40xx supports them in monochrome selanar supports Selanar graphics and bitgraph supports BBN Bitgraph terminals None have any options 91 34 49 60 Texdraw The texdraw terminal driver supports the LaTeX texdraw environment It is intended for use with texdraw sty and texdraw tex in the texdraw package It has no options 34 49 61 Tegif Tgif is an X11 based drawing tool it has nothing to do with GIF The tgif driver supports different pointsizes with set pointsize different label fonts and font sizes e g set label Hallo at x y font Helvetica 34 and multiple graphs on the page The proportions of the axes are not changed Syntax set terminal tgif portrait landscape lt x y gt solid dashed lt fontname gt lt f
199. the tic mark format to 7 0f or some other appropriate format This appears to have been fixed in SunOS 4 0 Another bug On a Sun3 under SunOS 4 0 and on Sun4 s under Sys4 3 2 and SunOS 4 0 the sscanf routine incorrectly parses 00 12 with the format f f and reads 0 and 0 instead of 0 and 12 This affects data input If the data file contains x coordinates that are zero but are specified like 00 000 etc then you will read the wrong y values Check any data files or upgrade the SunOS It appears to have been fixed in SunOS 4 1 1 Suns appear to overflow when calculating exp x for large x so gnuplot gets an undefined result One work around is to make a user defined function like e x x lt 500 0 exp x This affects plots of Gaussians exp x x in particular since x x grows quite rapidly Microsoft C 5 1 has a nasty bug associated with the g format for printf When any of the formats 28 1g 0g g are used printf will incorrectly print numbers in the range le 4 to le 1 Numbers that should be printed in the e format are incorrectly printed in the f format with the wrong number of zeros after the decimal point To work around this problem use the e or f formats explicitly gnuplot when compiled with Microsoft C did not work correctly on two VGA displays that were tested The CGA EGA and VGA drivers should probably be rewritten to use the Microsoft C graphics library gnuplot c
200. ticals in splot the top four bits control the edges on top of the splot In detail the lt integer gt should be the sum of the appropriate entries from the following table Graph Border Encoding Integer value of selection bit plot border splot splot Side splot base verticals top bottom south 1 16 256 left west 2 32 512 top north 4 64 1024 right east 8 128 2048 The default is 31 which is all four sides for plot and base and z axis for splot Using the optional lt line_style gt lt line_type gt and lt line_width gt specifiers the way the border lines are drawn can be influenced limited by what the current terminal driver supports By default the border is drawn with twice the usual linewidth The lt line_width gt specifier scales this default value for example set border 15 lw 2 will produce a border with four times the usual linewidth Various axes or combinations of axes may be added together in the command To have tics on edges other than bottom and left disable the usual tics and enable the second axes Examples Draw all borders set border Draw only the SOUTHWEST borders 41 set border 3 Draw a complete box around a splot set border 4095 Draw a partial box omitting the front vertical set border 127 256 512 Draw only the NORTHEAST borders set noxtics set noytics set x2tics set y2tics set border 12 34 7 Boxwidth The set boxwidth command is used to set
201. ting that the point is to be at the left right or center of the text Labels outside the plotted boundaries are permitted but may interfere with axis labels or other text If rotate is given the label is written vertically if the terminal can do so of course If one or more axis is timeseries the appropriate coordinate should be given as a quoted time string according to the timefmt format string See set xdata and set timefmt The EEPIC Imagen LaTeX and TPIC drivers allow in a string to specify a newline Examples To set a label at 1 2 to y x use set label y x at 1 2 To set a Sigma of size 24 from the Symbol font set at the center of the graph use set label S at graph 0 5 0 5 center font Symbol 24 To set a label y x 2 with the right of the text at 2 3 4 and tag the label as number 3 use set label 3 y x 2 at 2 3 4 right To change the preceding label to center justification use set label 3 center To delete label number 2 use set nolabel 2 To delete all labels use set nolabel 54 To show all labels in tag order use show label To set a label on a graph with a timeseries on the x axis use for example set timefmt Zd m hy HH AM set label Harvest at 25 8 93 1 34 24 Linestyle Each terminal has a default set of line and point types which can be seen by using the command test set linestyle defines a set of line types and widths and point types and sizes so that you
202. tours on both the base and the surface If no option is provided the default is base See also set cntrparam for the parameters that affect the drawing of contours and set clabel for control of labelling of the contours The surface can be switched off see set surface giving a contour only graph Though it is possible to use set size to enlarge the plot to fill the screen more control over the output format can be obtained by writing the contour information to a file and rereading it as a 2 d datafile plot set nosurface set contour set cntrparam set term table set out filename splot set out contour info now in filename set term lt whatever gt plot filename In order to draw contours the data should be organized as grid data In such a file all the points for a single y isoline are listed then all the points for the next y isoline and so on A single blank line a line containing no characters other than blank spaces and a carriage return and or a line feed separates one y isoline from the next See also splot datafile If contours are desired from non grid data set dgrid3d can be used to create an appropriate grid See set dgrid3d for more information 34 12 Data style The set data style command changes the default plotting style for data plots Syntax set data style lt style choice gt show data style See set style for the choices If no choice is given the choices are listed show
203. tp ee gatech edu pub mac gnuplot and several X11 interfaces include three Tcl Tk located at the usual Tcl Tk repositories Part IV Bugs Floating point exceptions floating point number too large small divide by zero etc may occasionally be generated by user defined functions Some of the demos in particular may cause numbers to exceed the floating point range Whether the system ignores such exceptions in which case gnuplot labels the corresponding point as undefined or aborts gnuplot depends on the compiler runtime environment The bessel functions do not work for complex arguments The gamma function does not work for complex arguments As of gnuplot version 3 7 all development has been done using ANSI C With current operating system compiler and library releases the OS specific bugs documented in release 3 5 now relegated to old_bugs may no longer be relevant Bugs reported since the current release may be located via the official distribution site ftp ftp dartmouth edu pub gnuplot http www cs dartmouth edu gnuplot_info html Please e mail any bugs to bug gnuplot dartmouth edu 115 39 Old_bugs There is a bug in the stdio library for old Sun operating systems SunOS Sys4 3 2 The g format for printf sometimes incorrectly prints numbers e g 200000 0 as 2 Thus tic mark labels may be incorrect on a Sun4 version of gnuplot A work around is to rescale the data or use the set format command to change
204. ts Eventually all drawings are done with piecewise linear strokes This number controls the number of line segments used to approximate the bspline or cubicspline curve Number of cubicspline or bspline segments strokes points number of linear segments order Order of the bspline approximation to be used The bigger this order is the smoother the resulting contour Of course higher order bspline curves will move further away from the original piecewise linear data This option is relevant for bspline mode only Allowed values are integers in the range from 2 linear to 10 levels Selection of contour levels controlled by auto default discrete incremental and lt n gt number of contour levels limited to MAX_DISCRETE_LEVELS as defined in plot h 30 is standard For auto lt n gt specifies a nominal number of levels the actual number will be adjusted to give simple labels If the surface is bounded by zmin and zmax contours will be generated at integer multiples of dz between zmin and zmax where dz is 1 2 or 5 times some power of ten like the step between two tic marks For levels discrete contours will be generated at z lt zl gt lt z2 gt as specified the number of discrete levels sets the number of contour levels In discrete mode any set cntrparms levels lt n gt are ignored For incremental contours are generated at values of z beginning at lt start gt and increasing by lt increment gt
205. ts the Apollo Graphics Primitive Resource with rescaling after window resizing It has no options If a fixed size window is desired the gpr terminal may be used instead 67 34 49 5 Atari ST via AES The atari terminal has options to set the character size and the screen colors Syntax set terminal atari lt fontsize gt lt col0 gt lt col1 gt lt col15 The character size must appear if any colors are to be specified Each of the up to 16 colors is given as a three digit hex number where the digits represent RED GREEN and BLUE in that order The range of 0 15 is scaled to whatever color range the screen actually has On a normal ST screen odd and even intensities are the same Examples set terminal atari 4 use small 6x6 font set terminal atari 6 0 set monochrome screen to white on black set terminal atari 13 0 fff f00 fO f ff fOf set first seven colors to black white green blue cyan purple and yellow and use large font 8x16 Additionally if an environment variable GNUCOLORS exists its contents are interpreted as an options string but an explicit terminal option takes precedence 34 49 6 Atari ST via VDI The vdi terminal is the same as the atari terminal except that it sends output to the screen via the VDI and not into AES Windows The vdi terminal has options to set the character size and the screen colors Syntax set terminal vdi lt fontsize gt lt col0 gt lt col1 gt l
206. umed to be infinity The increment may be negative If neither lt start gt nor lt end gt is given lt start gt is assumed to be negative infinity lt end gt is assumed to be positive infinity and the tics will be drawn at integral multiples of lt step gt If the axis is logarithmic the increment will be used as a multiplicative factor Examples Make tics at 0 0 5 1 1 5 9 5 10 set xtics 0 5 10 Make tics at 10 5 0 5 10 set xtics 5 Make tics at 1 100 1e4 1e6 1e8 set logscale x set xtics 1 100 10e8 The explicit lt label gt lt pos gt form allows arbitrary tic positions or non numeric tic labels A set of tics is a set of positions each with its own optional label Note that the label is a string enclosed by quotes It may be a constant string such as hello may contain formatting information for converting the position into its label such as 3f clients or may be empty See set format for more information If no string is given the default label numerical is used In this form the tics do not need to be listed in numerical order Examples set xtics low 0 medium 50 high 100 set xtics 1 2 4 8 16 32 64 128 256 512 1024 set ytics bottom 0 10 top 20 107 In the second example all tics are labelled In the third only the end tics are labelled However they are specified tics will only be plotted when in range Format or omission of the t
207. until the number of contours is reached lt end gt is used to determine the number of contour levels which will be changed by any subsequent set cntrparam levels lt n gt If the command set cntrparam is given without any arguments specified the defaults are used linear 5 points order 4 5 auto levels Examples set cntrparam bspline set cntrparam points 7 set cntrparam order 10 To select levels automatically 5 if the level increment criteria are met set cntrparam levels auto 5 To specify discrete levels at 1 37 and 9 set cntrparam levels discrete 1 1 exp 1 9 To specify levels from 0 to 4 with increment 1 set cntrparam levels incremental 0 1 4 To set the number of levels to 10 changing an incremental end or possibly the number of auto levels set cntrparam levels 10 To set the start and increment while retaining the number of levels set cntrparam levels incremental 100 50 See also set contour for control of where the contours are drawn and set clabel for control of the format of the contour labels and linetypes 34 11 Contour set contour enables contour drawing for surfaces This option is available for splot only Syntax 44 set contour base surface both set nocontour show contour The three options specify where to draw the contours base draws the contours on the grid base where the x ytics are placed surface draws the contours on the surfaces themselves and both draws the con
208. uplot_info html Before seeking help please check the FAQ Frequently Asked Questions list If you do not have a copy of the FAQ you may request a copy by email from the Majordomo address above ftp a copy from ftp ftp ucc ie pub gnuplot faq ftp ftp gnuplot vt edu pub gnuplot faq or see the WWW gnuplot page When posting a question please include full details of the version of gnuplot the machine and operating system you are using A small script demonstrating the problem may be useful Function plots are preferable to datafile plots If email ing to info gnuplot please state whether or not you are subscribed to the list so that users who use news will know to email a reply to you There is a form for such postings on the WWW site 4 What s New in version 3 7 Gnuplot version 3 7 contains many new features This section gives a partial list and links to the new items in no particular order 1 fit f x file via uses the Marquardt Levenberg method to fit data This is only slightly different from the gnufit patch available for 3 5 2 Greatly expanded using command See plot using 3 set timefmt allows for the use of dates as input and output for time series plots See Time Date data and timedat dem 4 Multiline labels and font selection in some drivers 5 Minor unlabeled tics See set mxtics 6 key options for moving the key box in the page and even outside of the plot putting a title on it and a box around
209. ur additional columns or using entries these additional values are used in different ways by the various errorbar styles In the default situation gnuplot expects to see three four or six numbers on each line of the data file either x y ydelta x y ylow yhigh x y xdelta x y xlow xhigh x y xdelta ydelta or x y xlow xhigh ylow yhigh The x coordinate must be specified The order of the numbers must be exactly as given above though the using qualifier can manipulate the order and provide values for missing columns For example plot file with errorbars plot file using 1 2 sqrt 1 with xerrorbars plot file using 1 2 1 3 1 3 4 5 with xyerrorbars The last example is for a file containing an unsupported combination of relative x and absolute y errors The using entry generates absolute x min and max from the relative error The y error bar is a vertical line plotted from x ylow to x yhigh If ydelta is specified instead of ylow and yhigh ylow y ydelta and yhigh y ydelta are derived If there are only two numbers on the record yhigh and ylow are both set to y The x error bar is a horizontal line computed in the same fashion To get lines plotted between the data points plot the data file twice once with errorbars and once with lines but remember to use the notitle option on one to avoid two entries in the key The error bars have crossbars at each en
210. vantage if any of the mp terminal over a postscript terminal is editable output Considerable effort went into making this output as clean as possible For those knowledgeable in the Metapost language the default line types and colors can be changed by editing the arrays lt and col The choice of solid vs dashed lines and color vs black lines can be change by changing the values assigned to the booleans dashedlines and colorlines If the default tex option was in effect global changes to the text of labels can be achieved by editing the vebatimtex etex block In particular a LaTeX preamble can be added if desired and then LaTeX s built in size changing commands can be used for maximum flexibility Be sure to set the appropriate MP configuration variable to force Metapost to run LaTeX instead of plainTeX 34 49 41 Mer The mgr terminal driver supports the Mgr Window system It has no options 34 49 42 Mif The mif terminal driver produces Frame Maker MIF format version 3 00 It plots in MIF Frames with the size 15 10 cm and plot primitives with the same pen will be grouped in the same MIF group Plot primitives in a gnuplot page will be plotted in a MIF Frame and several MIF Frames are collected in one large MIF Frame The MIF font used for text is Times Several options may be set in the MIF 3 00 driver Syntax set terminal mif colour monochrome polyline vectors help colour plots lines with line types gt 0 i
211. where you just supply the startup values in a file and can later use update to copy the results back into another or the same parameter file The via varl var2 form is best used interactively where the command history mechanism may be used to edit the list of parameters to be fitted or to supply new startup values for the next try This is particularly useful for hard problems where a direct fit to all parameters at once won t work without good starting values To find such you can iterate several times fitting only some of the parameters until the values are close enough to the goal that the final fit to all parameters at once will work Make sure that there is no mutual dependency among parameters of the function you are fitting For example don t try to fit a exp x b because a exp x b a exp b exp x Instead fit either a exp x or exp x b A technical issue the parameters must not be too different in magnitude The larger the ratio of the largest and the smallest absolute parameter values the slower the fit will converge If the ratio is close to or above the inverse of the machine floating point precision it may take next to forever to converge or refuse to converge at all You will have to adapt your function to avoid this e g replace parameter by 1e9 parameter in the function definition and divide the starting value by 1e9 If you can write your function as a linear combination of simple functions weighted by t
212. with 0 0 at bottom left and 1 1 at top right If the coordinate system for x is not specified first is used If the system for y is not specified the one used for x is adopted If one or more axis is timeseries the appropriate coordinate should be given as a quoted time string according to the timefmt format string See set xdata and set timefmt gnuplot will also accept an integer expression which will be interpreted as seconds from 1 January 2000 9 Environment A number of shell environment variables are understood by gnuplot None of these are required but may be useful If GNUTERM is defined it is used as the name of the terminal type to be used This overrides any terminal type sensed by gnuplot on start up but is itself overridden by the gnuplot or equivalent start up file see start up and of course by later explicit changes On Unix AmigaOS AtariTOS MS DOS and OS 2 GNUHELP may be defined to be the pathname of the HELP file gnuplot gih On VMS the logical name GNUPLOT HELP should be defined as the name of the help library for gnuplot The gnuplot help can be put inside any system help library allowing access to help from both within and outside gnuplot if desired On Unix HOME is used as the name of a directory to search for a gnuplot file if none is found in the current directory On AmigaOS AtariTOS MS DOS and OS 2 gnuplot is used On VMS SYS LOGIN is used See help start up On Unix PAGER is used a
213. x gt will be plotted xrange and yrange are affected the ranges can be set as if the graph was of r t rmin with rmin added to all the labels Any range may be partially or totally autoscaled although it may not make sense to autoscale a para metric variable unless it is plotted with data Ranges may also be specified on the plot command line A range given on the plot line will be used for that single plot command a range given by a set command will be used for all subsequent plots that do not specify their own ranges The same holds true for splot Examples To set the xrange to the default set xrange 10 10 To set the yrange to increase downwards set yrange 10 10 To change zmax to 10 without affecting zmin which may still be autoscaled set zrange 10 To autoscale xmin while leaving xmax unchanged set xrange 34 75 Xtics Fine control of the major labelled tics on the x axis is possible with the set xtics command The tics may be turned off with the set noxtics command and may be turned on the default state with set xtics Similar commands control the major tics on the y z x2 and y2 axes Syntax 106 set xtics axis border no mirror no rotate autofreq lt incr gt lt start gt lt incr gt lt end gt lt label gt lt pos gt lt label gt lt pos gt set noxtics show xtics The same syntax applies to ytics ztics x2tics and y2tics axis or b
214. xiting 30 Replot The replot command without arguments repeats the last plot or splot command This can be useful for viewing a plot with different set options or when generating the same plot for several devices Arguments specified after a replot command will be added onto the last plot or splot command with an implied separator before it is repeated replot accepts the same arguments as the plot and splot commands except that ranges cannot be specified Thus you can use replot to plot a function against the second axes if the previous command was plot but not if it was splot and similarly you can use replot to add a plot from a binary file only if the previous command was splot N B use of plot 3 replot is not recommended gnuplot does not store the inline data internally so since replot appends new information to the previous plot and then executes the modified command the from the initial plot will expect to read inline data again Note that replot does not work in multiplot mode since it reproduces only the last plot rather than the entire screen See also command line editing for ways to edit the last plot splot command 31 Reread The reread command causes the current gnuplot command file as specified by a load command or on the command line to be reset to its starting point before further commands are read from it This essentially implements an endless loop of the commands from the be

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