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1. PREEMPTION allows a message displace another message from the IL of a R type node and to put itself in that IL 56 CHAPTER 6 INSTRUCTIONS 18 REL makes a message to go out of the IL of a R type node 19 RELEASE manages the message released in a R type node 20 REPORT allows to write an output report in a file 21 SCAN examines a list of messages allowing changes and extractions 22 SELECT selects messages from the different EL of a D type node 23 SENDTO sends messages in process to lists 24 STATE allows to change status variables and control activations of a G type node 25 STAY indicates the time of staying of a message in the IL of a R type node and gives that value to a variable STAY 26 SYNCHRONIZE retains a certain number of messages in the EL to release them together at the same time 27 TSIM sets the duration of the simulation run and gives that value to a variable TSIM 28 TITLE allows to put titles to the experiments 29 UNLOAD releases the memory of an array used to import a DBASE IV table 30 USE allows to define the quantity of resource to be used by a message in a R type node and puts this value in a variable USE In the following the syntax and function of each one of these instructions are described A sign is put after each instruction This separator may be omitted before an END or ELSE separator 6 1 ASSEMBLE assembles messages in a representative message Syntax ASSEMBLE ELIM FI
2. h the help of GLIDER Except those of C or D type can have a subscript or index that can take values 1 2 until a maximum value that must be declared by the user in the node heading Indexed nodes are equivalent to a set of are use no to represent sets of similar subsystems es of the same type equal to the declared maximum These nodes share a common code They When activated during the scan of the network they are activated sequentially When activated by an event that refers INO takes to be able node is dec e ared as arrays in PASCAL i e in the form 1 N Examp Window R 1 5 Exiti Exit2 lt code gt oland A type nodes only the node with the index of the event is activated An index variable he value of the index of the currently executed node The user has access to that index in order o control differences when processing the common code The multiplicity or dimension of the This line declares that the node named Window is of R type its successor nodes consists in 5 nodes that share the lt code gt The nodes without index are called simple those with index are called multiple nodes of a multiple node is called its dimension or multiplicity The nodes of a multiple R type node can be of different capacity 1 4 Example 1 Simple Serving System CHAPTER 1 INTRODUCTION are Exitl and Exit2 It nodes The number of The problem is to compute the queues and waiting tim
3. Returns a REAL value of a random variable whose probability function is a GAMMA function with mean equal to the first lt real expression gt and deviation equal to the second lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 21 GAUSS random positive value from a Normal distribution Syntax GAUSS lt real expression gt lt real expression gt lt stream gt Returns a REAL value of a random variable whose probability function is a normal function in which only the positive values are considered The mean is equal to the first lt real expression gt and the standard deviation equal to the second lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 22 LOGNORM random value from a Lognormal distribution Syntax LOGNORM lt real expression gt lt real expression gt lt stream gt Returns a REAL value of a random variable whose probability function is a lognormal function with mean equal to the first lt real expression gt and deviation equal to the second lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 23 NORM RANDOM VALUE FROM A NORMAL DISTRIBUTION 103 8 23 NORM random value f
4. o o 9 11 3 6 Version 3 0 April 1994 and 3 1 September 1994 o ooo o 9 11 3 7 Version 4 0 July 1996 2 2 aaa 20 Chapter 1 INTRODUCTION 1 1 Characteristics of the GLIDER Simulation Language GLIDER is a language for simulation of both continuous and discrete systems The system to be simulated is seen as a set of subsystems that exchange information in different ways The subsystems can store transform transmit create and eliminate information GLIDER has the following features to represent systems and information processes e Subsystems are represented by nodes of a network Nodes may be of different types according to their functions e Information transformation is described and performed by program code associated to each node e Information exchange among nodes is done by the action of the code on shared variables or files and also by passing messages from a node to other e Information is stored in variables files or in lists of received messages in the nodes Two simple examples follow to give a general idea how GLIDER programs look like 1 1 1 Example of discrete simulation Railroad System In a simple railroad system trains with a number of coaches equal to a random number from 16 to 20 depart from a station each 45 minutes After 25 minutes of travel the trains reach their destination The program writes the time of arrival and the number of coaches For clarity in all the
5. A number of copies equal to the actual value of N_Offices are generated and sent with an indication of its number plus one to the nodes Office 2 Office 3 etc The original is sent to Office 1 2 The following code may be used to initialize a simulation of a queue system with the system not empty Six messages are sent at TIME with 10 value to the node Bridge with a negative generation time Entrance I Bridge IT EXPO Tel1 SENDTO Bridge FillSys 1 GT 10 TIME GT SENDTO Bridge COPYMESS 5 BEGIN GT Ant LICOPY TIME GT SENDTO Bridge END Bridge R STAY 1 INIT ACT FillSys 0 ASSI Ant 1 5 9 7 3 2 0 The node FillSys creates a virtual past before TIME 0 in which it sends six messages to Bridge It finishes its action when he puts TIME to zero Ant 5 6 4 CREATE creates a message Syntax CREATE lt message name gt lt node gt lt associated instruction gt This instruction is used to create messages in nodes that are not of I type It creates a message with the structure defined in the declaration MESSAGES with the name indicated in lt message name gt If lt node gt is used this may be a name of aI type node and the structure of the created message will be that of the messages that can be created by that I type node It may also be a general type node for which a message structure has been defined After one message is created the lt associated inst
6. The differences with the previous beta version were the inclusion of Node type C with the METHOD Euler and Runge Kutta Fehlberg e Instruction GRAPH e Instruction ASSI e Instruction FILE e Instruction INTI e Instruction OUTG e Procedure DEACT e Important changes in the instructions ASSEMBLE SCAN SELECT SYNCHRONIZE e Elimination of the instructions MOVE SPLIT COUNT SENDTOF e Instruction COPY Functions MAX MAXI MIN MINL Random functions BETA BER GAMMA LOGNORM POISSON TRIA WEIBULL The GLIDER environment without the graphic facility The syntactical editor 11 3 DIFFERENCES OF VERSION 4 0 JULY 1996 WITH THE PREVIOUS VERSIONS 11 3 4 Version 1 1 May 1992 It included Node type A METHOD Runge Kutta RK4 LABEL and VAR as local variable of a node Functions GAMMA BETA LOGNORM Interpolation with SPLINE Function MODUL Graphic facility to develop the model 11 3 5 Version 2 0 May 1993 and Version 2 1 November 1993 It included Change of the instruction NODE to the instruction MESSAGES The instruction TRANS The instructions REPORT ENDREPORT Change in ASSEMBLE EQUFIELDS The instruction FILE A new editor 11 3 6 Version 3 0 April 1994 and 3 1 September 1994 It included Possibility to use MODULE to divide the network in units 119 Possibility to connect with a data base DBASE IV instructions LOAD UNLOAD DBUPDATE Procedure RET
7. BLUE GREEN CYAN RED MAGENTA BROWN LIGHTGRAY DARKGREY LIGHTBLUELIGHTGREEN LIGHTCYAN LIGHTRED LIGHTMAGENTXYELLOW WHITE For the background color the BLACK may also be used Descriptors are separated by Up to 14 variables may be represented in a graph GRAPH may be used in any node but it must be executed only one time during each activation If there are many GRAPH instructions only one must be executed in a simulation run When TIME is used as independent variable and a screen is full the display is stopped alf a second the displayed graph is erased and the display continues in a new screen The user can use the ey PAUSE to stop the graphic and then to re start the simulation with any key It is possible to control the orizontal scale by changing the interval of the successive activations of the node that contains the GRAPH instruction The more frequent the activations the more extended is the graph The horizontal axis of the screen is divided in 10 parts If the total length of the axis is for example 531 ixels the number of horizontal pixels in the total screen assumed 640 minus 17 for a free space at both sides each part has 83 pixels At each new call and execution of the instruction GRAPH the new point is advanced one pixel so it takes 83 time units to advance a part If successive calls are made each 0 125 time units the part represents the part of the curve generated in 83 0 125 6 64 units of simulation time If he calls are
8. and the successor he code may follows The code is writ eginning of a line indicates the end of The structured instructions of GLIDER like STAY 6 the procedures like ACT in Chap each user programmed node the compi system provided code to perform the o is executed when the node is activated is word as the first in the first line o however be included at any place in w rogram The name of each node mus The heading of a node also includes s nodes The characters terminate en in free format from column 1 to 75 he NETWORK section See Chapters 4 hat can be used to put the title of the program author date etc An The only restriction is e separator to the next the section comments ich a blank is allowed be at the beginning of he type of the node a he heading after them The word INIT at the and 5 for more details lt expression are described in Chapter er 7 the functions like EXPO or GAU ler will generate a procedure that contains the user code and er operations of the node implied by i SS in Chapter 8 For s type This procedure 1 4 EXAMPLE 1 SIMPLE SERVING SYSTEM e INIT section contains instructions to give initial values to the variables and parameters for the simu lation run It may contain the specification of the total simulation time by assignation of the value to the system variable TSIM There are other ways to finish the simulation This section must contain at
9. arameter of the generated message The value uencies It is assigned to the field ShiTyp of the e Control o the port the GLIDER generated variable ree capacity of the node Pier ShiTyp The for the Pier 1 3 for the Pier 2 1 for the Pier 3 annel In this case it is 1 if the channel is free and e G node scans the EL of messages and executes ich is true the condition of the if there is free he SENDTO instruction is executed This extracts When activated by the scanning of the ecause the 1 that means that no message is using the resource a later time given by the user defined variable TChannel When the automatically managed because there is a RELEASE instruction of dimension 3 Each node represents a e capacity of each node erent of 1 the user has to define ion USE 1 i e it is assumed e different with ship of very different size ier is taken from a Gamma dis e values of the means are assigned in the INIT section Notice that o 4 After the operation it is sent to Channel an ype It takes each message of its EL executes the ion of the time spent in the system The GT is eeps its generation time As TIME is the value of the actua message remained in the system The procedure TAB put this value in the frequency table In the instruction associated to the RELEASE the message is 2 or 3 it is sen at will be assigned to t respectively to the Pier 1 Pier 2 or Pier 3 e ships abandoning
10. TabVeh TEXT 2 4 NODES In this section the user may instruct GLIDER to assign IL and or EL to general type nodes declared in the NETWORK section The declarations must have the heading NODES After this one or more declarations follow The declaration syntax is lt node identifier gt EL IL EL IL lt node identifier gt is the name of a general type node Index must not be included in this declaration According to the arguments the node will have EL or IL or both Examples NODES Synchr EL Proc EL IL 24 CHAPTER 2 DECLARATIONS 2 5 MESSAGES In this section the user may define structures of messages with user s defined fields besides the default fields see 9 1 The declarations must have the heading MESSAGES After this one or more message declarations follow The declaration syntax is lt node identifier gt lt message identifier gt lt list of field declaration lt node identifier gt is the name of aI type node Index must not be included in this declaration The declaration defines the structure of the messages generated at that Input type node lt message identifier gt is an identifier that may be used by a CREATE instruction to generate messages with the declared structure The CREATE instruction may be used in any node except I type nodes lt list of field declaration gt is a list of field declarations with the same syntax that the RECORD structure declaration Examples Shi
11. VAR z Arr5 X Arr5 Note the use of the sign for new type declarations whereas the sign is used for type specification in variable declarations New types declarations are mandatory in Pascal when the user needs to pass a structured variable in the arameter list of a function or procedure as Pascal syntax only accepts type identifiers in parameter list declarations The reader may consult Pascal and TurboPascal bibliography for a complete description on types Restric ions or changes in GLIDER to Pascal syntax and use will be stated when appropriate GLIDER includes the following predefined types and type constructors for new type declarations or variable ype specifications 2 1 1 Simple types The following table shows the set of simple types in GLIDER Besides the simple Pascal types GLIDER adds the CONT RET and FREQ simple types REAL Real numbers INTEGER Integer numbers LONGINT Long integer numbers BOOLEAN Logic values TRUE or FALSE CHAR ASCII character set WORD Non negative integers BYTE Non negative integers in the range 0 255 STR80 ASCII character set TEXT ASCII character set CONT Continuous for variables with derivatives in differential equations Must be used in VAR only for a list of contiguous variables See 4 7 2 1 TYPE 19 RET Retard To be used in the RETARD procedure Must be used in VAR only See 7 17 FREQ For component type of arrays to be used as multivariate frequency
12. WEIBULL lt real expression gt lt real expression gt lt stream gt Returns a value of a random variable whose probability function is a function with first parameter equal to the first lt real expression gt and second parameter equal to the second lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed Chapter 9 RESERVED WORDS The GLIDER system defines a set of identifiers as reserved words They cannot be defined by the user 9 1 Message variables GT real generation time of the message being processed e O_GT real generation time of the message being processed ET real time of entry of the message to the actual list e O_ET real time of entry of the alternative message to the actual list XT real time of exit of the message from the actual list e O_XT real time of exit of the message from the actual list USE real quantity of resource to be used by the message e O_USE real quantity of resource to be used by the alternative message NUMBER integer generation number in its origin node of the message being processed NODE string name of the origin node of the message being processed O_NUMBER integer generation number in its origin node of the alternative message being pro cessed O_NODE string name of the origin node of the alternative message being processed e REMA real its v
13. ACT Gra2 0 END C1 0 0625 DT_C2 0 0625 0 R 1 X 1 0 X 2 0 X 3 1 Z 0 S 1 D Y DECL VAR X ARRAY 1 3 OF CONT Z S Y R CONT Tc INTEGER END 4 8 A Autonomous type nodes These nodes execute their code at scheduled times They have neither EL nor IL They may activate themselves and other nodes change variables and send messages 4 8 1 Code It may contain Pascal instructions functions and procedures GLIDER common instructions and proce dures GLIDER functions and the GLIDER instructions CREATE and SENDTO The common instruction UPDATE can only be used in the associated instruction of CREATE or SENDTO 4 8 2 Activation An A type node is only activated by an event that refers to it It is not activated again during the scanning of the network If the node is multiple only the node with index value equal to the index of the event is activated 4 8 3 Function When the node is activated the code is executed 4 8 4 Relation with other nodes It have not predecessors but may have successors if messages are created in it and sent to other nodes 4 8 5 Indexes A multiple type A node is a set of independent nodes that can be activated independently 4 8 6 Examples 1 Print A IT 365 Annual Each 365 unit times the procedure Annual is called for instance to print a report of the state of the model The node must be activated for the first time from other nod
14. Aa Bb Cc Dd VAR Let Letters GFUNCTIONS Poli POLYG REAL REAL 7 Spli1 SPLINE REAL REAL 5 Sp1i2 SPLINE REAL REAL 10 Sp1i3 SPLINE REAL REAL 10 Esca STAIR REAL REAL 7 FrecR FREQ REAL REAL 8 FrecA FREQ INTEGER REAL 8 DiscoN DISC INTEGER REAL 11 DiscoA DISC Letters REAL 11 DiscoR DISC REAL REAL 10 When the INTI is executed a graph of Poli appears on the screen If the user press 2 in the mouse the system continues displaying the graph of Split The XY points indicated in the program are shown 68 CHAPTER 6 INSTRUCTIONS as small circles and the curve is plotted When a graph is shown and the user press 1 in the mouse with the cursor in a point the following cases may occur a The cursor is on a point of the function For instance in the Sp1i1 the cursor is in X 45 Y 80 or within the circle at this point Then this point is deleted and a new graphic without it appears b The cursor is very near in X to one of the points but with a different ordinate Y For instance in X 45 003 Y 63 5 in the example Sp1i1 Then the old near X remains but the old Y is substituted by the new one In the example the point 45 80 is replaced by 45 63 5 The new graph is displayed c The cursor is clearly away from all XY defined points Then if the X is REAL a new point is introduced If the X is scalar or INTEGER the Y is assigned to the nearest X the Y is changed but no new X
15. IF Level 123 0 THEN CREATE Mess SENDTO Center may fail if Level do not reach exactly that value If we put 52 CHAPTER 5 NETWORK Tank C Level Inflow K Level IF Level gt 123 0 THEN CREATE Mess SENDTO Center after the value is reached a message is sent during each integration interval One solution may be Tank C Level Inflow K Level IF MesNotSent and Level gt 123 0 THEN CREATE Mess BEGIN SENDTO Control MesNotSent FALSE END MesNotSent is a boolean variable originally TRUE When the condition is fulfilled for the first time a message is sent and MesNotSent becomes FALSE so no more messages are sent Chapter 6 INSTRUCTIONS GLIDER instructions are structured instructions characterized by a name a list of parameters that may be variable in length and in many cases an associated simple or structured instruction This last may contain certain GLIDER instructions and procedures In this sense they are like structured instructions of general purpose languages GLIDER instructions execute complex procedures and are translated into many basic instructions and procedure calls They are used to create and copy messages to manage the movements of messages to examine and change the entry and internal lists of the nodes to write or read files to make graphics etc In this chapter the following conventions and definitions are used e names of the elements of the language are put
16. NODE WINDOW EVENT 1 IEV 1 NODE ENTRY 1 ADD TO FEL EV 1 IEV 1 TIME ADD MESS NODE WINDOW 1 EXA MESS NODE WINDOW 1 EXA MESS Future Event List at Time WINDOW ENTRY NODE NODE 5 3 3 GEN GEN GEN FORO E E E E E E E E E E EE gt gt gt gt gt gt a gt gt gt a 4 108 ENTRY TO ENTRY ENTRY 0 888 T 4 108 T 4 409 IND IND FORO E E E E E E E E E E EE gt gt gt gt gt gt a gt gt gt a 7 614 ENTRY TO ENTRY ENTRY 4 108 T 4 409 T 7 614 IND IND FORO E E E E E E E E E E EE gt gt gt gt gt gt a gt gt gt a SEEK EXIT TIME ENTRY FROM ENTRY TO ENTRY ENTRY FROM 7 784 ENTRY TO ENTRY 1 TIME ENTRY FROM GENERATED IN ENTRY 4 409 T 7 614 T 7 784 IND IND FORO E E EE E E E E E E EE gt gt gt AAA D a 7 917 ENTRY TO ENTRY ENTRY 7 614 T 7 784 T 7 917 IND IND EL_WINDOW 1 1 EVP 1 EVP EL_WINDOW 1 1 EVP 1 EVP 4 409 IL_WINDOW 1 EL_EXIT 1 EL_WINDOW 1 IL_WINDOW 1 EL_EXIT 1 ENTRY AT 1 EVP 1 EVP EL_WINDOW 1 1 EVP 1 EVP LL LL LL LL LL LL LL 0 000 LL TIME 1 TIME TIME 2 TIME TIME 1 TIME O TIME 3 TIME O TIME 1 TIME TIME 2 TIME CHAPTER 1 INTRODUCTION 0 888 0 888 4 108 4 108 4 409 4 409 4 409 4 409 4 409 4 409 7 614 7 614 1 4 EXAMPLE 1 SIMPLE SERVING SYSTEM EVENT 2 IEV LOR RRR KK
17. TYPE Mo January February March April May June July August September October November December 2 1 TYPE 21 DayType 1 31 VAR Birthday RECORD Month Mo Day DayType Year WORD END Bounty Ship PConvoy PShip The Ship record type has a pointer type field for building lists of records of this type In VAR a type record variable Bounty is defined The pointer variable PConvoy can be used to construct a list of records of type Ship The record variable Birthday has fields type Mo with the values of the months and Day whose values range from 1 to 31 The field Year is of the predefined type WORD for this reason it can take values from 1 to 65535 Fields of a record type variable are referred to by the variable name followed by the character followed by the field name Example Birthday Year refers to the value of the field Year in the variable Birthday FILE To declare as new type unlimited successions of components of a specified type The system manages the existence of the components of a file type variable in external I O devices at run time The syntax is lt file type identifier gt FILE OF lt type identifier gt lt type identifier gt must not be another file type identifier or any structured type identifier with a file type identifier as component type Example FileShip FILE OF Ship The Pascal predefined type TEXT is a file of CHAR type for which Pascal has special variable
18. They are ACT BEGINSCAN BLOCK ASSI CLRSTAT DEACT DEBLOCK DBUPDATE DOEVENT DONODE ENDSIMUL EXTFEL EXTR FILE FREE GRAPH INTI IT LOAD MENU NT OUTG PAUSE PUTFEL REL REPORT SCAN SORT STAT STOPSCAN TAB TITLE TRACE TRANS TSIM UNLOAD UNTRACE UP DATE USE BEGINSCAN and STOPSCAN are included here because they can be used in any nodes as part of the associate instruction of SCAN lt structured GLIDER instructions gt are the following a brief comment about the function is indi cated ASSEMBLE assembles various messages in a representative message ASSI assigns values to arrays and multiple nodes COPY makes copies of a message CREATE creates a message DBUPDATE updates a DBASE table DEASSEMBLE disassembles messages put together by an ASSEMBLE DOEVENT makes the associated instruction executed only one time each event wo 1 Do oT FF WN FR DONODE makes the associated instruction executed only one time and only if the event starts in the node EXTR extracts a message from a list FILE writes values in a file GRAPH draws graphics during a run INTI allows interactive changes of data values IT schedules a new activation of the node after an Interval Time ahead the actual time LOAD imports the content of a DBASE IV table to an array NT schedules a new activation of the node at a future time OUTG writes variable and array values with titles NOT F WN AO
19. global variables files fields of the messages The messages are structured like records in the Pascal language The user can declare different types of records with different types of fields They may be used to represent entities traveling from one node to another e Information is stored in variables files and in messages Messages are stored in two basic lists that are associated with some nodes EL Entry List of received messages to be processed by the node They may be used to represent queues or waiting lines IL Internal List where messages can be stored until they are extracted Usually they are used to represent entities using a facility or remaining in delay lines CHAPTER 1 INTRODUCTION The abbreviations EL and IL will be respectively used for Entry List and Internal List with the plurals ELs and ILs In addition to the global variables and variables ocal to nodes that are declared by the user the system introduces global field variables for each field of each message structure declared by the user The name of assed When messages of different s field variable This allows The execution of the code it may be necessary to schedu called FEL Future Event Lis o the node to be activate ructure have some o deal wi of a node le the activation of cer Eac and the hese variables is equal to the name of the field When a message is processed the values of the fields of the message are transferr
20. lt real expression gt when the division is performed until the units in the quotient Example MODUL 804 364 25 is computed by dividing 804 364 25 2 MODUL 804 364 25 is computed by 804 2 364 25 75 5 assuming the year equal to 364 25 days 804 days are 2 years plus 75 5 days 8 15 BER random value from a Bernoulli distribution Syntax BER lt real expression gt lt stream gt Returns the BOOLEAN value TRUE with a probability equal to the value of lt real expression gt and FALSE with a probability of 1 lt real expression gt The probabilities are computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed Example IF BER 0 6 THEN SENDTO LargeDep ELSE SENDTO SmallDep At random 60 of the times the messages are sent to LargeDep 40 to SmallDep 8 16 BETA random value from a Beta distribution Syntax BETA lt real expression gt lt real expression lt stream gt Returns a REAL value of a random variable whose probability function is a BETA function with first param eter equal to the first lt real expression gt and second parameter equal to the second lt real expression computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 17 BIN random value from a Binomial distribution Syntax BIN lt integer expression lt inte
21. the available capacity If there is not enough capacity the message remains in the EL When the departing event is executed the message is removed from the IL and sent to the successor nodes So the node has two function an accepting function that assigns resource to a message and put it in the IL and a departing function that extracts the message of the IL and frees resource 4 4 1 Code The type R node may contain Pascal instructions functions and procedures GLIDER common instructions and procedures GLIDER functions the GLIDER instructions PREEMPTION RELEASE STAY If there is an instruction RELEASE only one is allowed it must be the first in the code Its associated instruction 4 4 may R RESOURCE TYPE NODES 39 contain Pascal instructions functions and procedures GLIDER common instructions and procedures and GLIDER functions the instructions SENDTO DEASSEMBLE EXTR CREATE and COPYMESS and 4 4 The he procedures NOTFREE BLOCK and DEBLOCK 2 Activation art of the code that processes the departing message that may be a system generated code or a user s programmed RELEASE instruction is only activated by a departing event that refers to the node This even must The can be only introduced in the FEL by the node itself when a STAY instruction is executed The node not be activated by an ACT instruction art that controls the entrance of the messages to the IL is activated during the scanning of th
22. the statistics ops the scan of a list of messages TAB adds a value to a frequency table TRACE starts the tracing 83 84 CHAPTER 7 PROCEDURES 24 TRANS sends an element from a list to another list 25 UNTRACE stops the tracing 26 UPDATE updates field variables or fields of a message This chapter notation is the same of the chapter 6 7 1 ACT schedules a future activation of a node Syntax ACT lt node name gt lt real expression gt It is used to schedule a node activation in a future time lt node lt real When lt node name gt is the name of the node to be activated expression gt is areal expression whose value indicates the time from now until the future activation his instruction is executed a future event is put in the FEL The event node is the indicated by name gt The time of the event is TIME lt real expression gt Here TIME is the system variable that contains the value of the actual simulation time The in tively ex and the event parameter of the event are the actual values of the variables INO and IEV respec This procedure can be used in nodes of any type Examp AC FO es SubwayDepart 0 ACT Controller 7 R i 1 TO 8 DO ACT Arrivals i EXPO TMBarr il The components of the multiple node Arrivals are activated for future times taken from an exponential distribution with mean values depending on the node 7 2 BEGINSCAN repeats t
23. 0 ACT Result 32000 DECL VAR Mul ARRAY 1 2 1 Zzz ARRAY 1 2 1 gt 1 2 OF FREQ 3 3 1 2 OF REAL 8 26 TRIA RANDOM VALUE FROM A TRIANGULAR DISTRIBUTION 105 VAL_Mul ARRAY 1 3 1 3 OF REAL I J K INTEGER END Example 2 Logs are processed by a set of machines The processing time was adjusted by regression to a linear function of the Length L and the Diameter D of the logs Logs arrive each 10 m with random sizes A frequency table aggregated in 3 diameters 32 36 40 inches and 4 lengths 15 25 35 45 feet obtained by sampling gives the quantity in each class NETWORK Arrivals I IT 10 RAND Fld L RANDV_Fld 1 D RANDV_F1d 2 Machines R STAY 8 5 0 32 L 0 21 D Dep E INIT ACT Arrivals 0 TSIM 2000 Machines 3 Multivariate frequency array D rows L columns ASSI Fld 1 3 1 4 Length feet 15 25 35 45 32 123 108 47 12 Diameter inches 36 89 104 99 43 40 22 87 106 172 values of the variables columns ASSI VAL_Fld 1 2 1 4 32 36 40 0 15 25 35 45 DECL VAR_Fld ARRAY 1 3 1 4 OF FREQ VAL_Fld ARRAY 1 2 1 4 OF REAL MESSAGES Arrivals L D REAL STATISTICS ALLNODES END 8 26 TRIA random value from a Triangular distribution Syntax TRIA lt real expression gt lt real expression gt lt real expression gt lt stream gt Returns a REAL
24. 0 possible values 3 3 Values to Functions Given by Pairs of Values These functions are defined in 2 6 To assign values to them a special assignation is used Its structure is lt name of the function gt lt list of pairs gt The pairs are separated by Each pair is lt value of argument gt lt value of function gt Examples Rain 0 23 31 24 59 23 81 37 111 42 141 48 171 39 202 37 232 35 263 33 293 30 329 25 365 23 Tax 0 0 1000 5 3000 18 5000 22 12000 35 FVehType 1 Car 2 Van 3 Truck FrVesselType 1 342 2 87 3 21 Assuming that the first is of type POLYG linear interpolation the value Rain 72 would be as the 72 fall in the interval 59 81 Rain 72 23 37 22 81 59 72 59 31 86 Rain 263 33 Rain 387 not defined Assuming that Tax is of STAIR type piecewise constant it would be 3 4 VALUES TO FREQUENCY TABLE PARAMETERS 31 Tax 514 0 Tax 2999 5 Tax 11500 22 Tax 12000 35 If VehType is of type DISC then VehType 3 Truck VehType 1 5 not defined Assuming that FVesselType is of FREQ type then the probability that its value is 2 would be 87 342 87 21 0 193333 3 4 Values to Frequency Table Parameters The definition of these tables is given in 2 7 To assign values to the parameters after a heading TABLES the following assignation have to be made lt table name gt lt initial value gt lt number of
25. 16 of REAL Follows Ptra END IfPTrain Ptra is declared in the VAR subsection of DECL then the pointer variable PTrain is supposed to point to a record with the shown structure The variable PTrain Wagon 3 refers to the third array element of the field Wagon of the Train type record pointed by PTrain These user s declared records are seldom used in GLIDER because messages suffices for almost all the uses and they are internally handled by GLIDER instructions and procedures Pointer variable value assignment results from dynamic memory allocation Pascal procedure NEW or from direct assignment of memory addresses values as returned by function ADDR for instance Pointer variables must be carefully used 20 CHAPTER 2 DECLARATIONS 2 1 3 Structured types Structured type constructors allow programmers to define as new types complex information structures with components of the same or different types They are e ARRAY To declare as new type a succession of a fixed quantity of components of the same type The components of a variable of any ARRAY type occupy contiguous memory locations and can be individually referred to by using one or more indexes The syntax of the type declaration is lt type identifier gt ARRAY ni1 nf1 OF lt component type for unidimensional arrays or lt type identifier gt ARRAY nil nf1 ni2 nf2 OF lt component type gt for multidimensional arrays Note that GLIDER
26. 2 Code Node code may be empty In this case no separator is required after If it is not empty it may be a succession of combinations of Pascal and GLIDER elements For instance e Simple Pascal instructions Example Results A TotCash TotNum Price Quant Quant 1 e Compound and structured Pascal instructions Example FindMax A M 0 FOR J 1 TO NTot DO IF Bag J gt M THEN M Bag J WRITELN The most heavy weights M e Compound and structured Pascal instructions including GLIDER instructions Example ConTower D IF International THEN SENDTO Runway_I ELSE SENDTO Runway_N e GLIDER instructions Example Robot1 X Robot2 ASSEMBLE ELIM 2 EQUFIELD L SENDTO Robot2 e GLIDER procedures Example Q1 L ORDER Temp A e Compound and structured Pascal instructions including GLIDER procedures and instructions Example ActDec A IF Danger THEN ACT Proc_Emer ELSE ACT Proc_Norm e A succession of the above items Restrictions in the use and order of the instructions in the code are explained in Chapter 4 5 2 PROCESSING THE NETWORK 51 5 2 Processing the network The processing of the network starts when a node is activated by an event The procedure in the node is executed After this a scanning of the network starts The successive nodes are examined one by one in the programming order if they are of G L D E R or general type The nodes o
27. C is selected the Initial Menu is called again Chapter 11 DEVELOPMENT OF GLIDER 11 1 The GLIDER group The development of the language started in 1985 from a proposal made by Renato Del Canto who par ticipated in the early meetings with Carlos Domingo and Marisela Hern ndez All them were working at the IEAC Institute for Applied Statistics and Computing of the Economy Faculty at Los Andes University M rida Venezuela The general outlines were designed by C Domingo and M Hern ndez during 1985 1986 and useful suggestions were made by Cristina Zoltan from Sim n Bolivar University Since 1986 a formal group constitued by Carlos Domingo Marta Sananes Giorgio Tonella Jos G Silva and Herbert Hoeger developed important features of the language and advised the implementation of the compiler made by C Domingo and the graphic input programmed by M Sananes G Tonella from the CESIMO Modeling and Simulation Research Centre of the Engineering Faculty was responsable for the development of ap plications that suggested new developments and improvements He also contributed with general key ideas linking the structure of the language with the general theory of simulation Important suggestions devel opments and applications were made in graduate and undergraduate thesis supervised by member of the GLIDER group such as Carlos Domingo Herbert Hoeger Marta Sananes Giorgio Tonella Omar Velandia 1990 Oscar Nufiez 1990 Cruz Mar
28. Chapter 2 for details Lexicographic remark e The text of the model must be written on columns 1 to 75 e The translator is case insensitive in the DOS version Window may be e Comments may be included within parenthesis or written WINDOW e The names of nodes in the node heading as Entry and sections as NETWORK must be the first names in its lines but can be preceded by comments otherwise the format is free 1 4 1 Description of the process Then the execution of the NETWORK section starts The components of t window and exit are represented by the nodes Entry Window and Exit in are represented by the messages that each node may send to its successor this case we could omit the explicit indication of successor the GLIDER sys successor by default An I type node or more exactly the procedure into w when activated generates a message and sends it to the end of the EL of t automatically by the GLIDER system In this node a next arrival event The execution of the program starts with the INIT section The total simulation time is assigned to the GLIDER variable TSIM The GLIDER variable TIME that keeps the value of the time during the simulation is initialized to 0 The user could put explicitly other assignation even a negative number The GLIDER procedure ACT schedules an activation for the actual time plus the second argument here also 0 but it may be a real expression so the first activation will happ
29. Function aoaaa aa 42 4 6 4 Relation with other nodes 2 2 ee 42 46 5 ladera 42 46 6 Example 42 CONTENTS v 4 7 C Continuous type of nodes oaa a aaa 42 4 71 Code noaa aaa 43 4 7 2 Activation aa aaa ee 43 4 7 3 Function oaa aaa 43 4 7 4 Relation with other nodes e eee 43 4 7 5 Indexes 2 2 2 43 4 7 6 Continuous Variables Declaration 2 o e 43 4 7 7 Examples oooga aaa 44 4 8 A Autonomous type nodes aaa aa 46 4 8 1 Code naaalala 46 4 8 2 Activation aaa aa 46 4 8 3 Function 0 en 46 4 8 4 Relation with other nodes 2 2 o e eee 46 4 8 5 Indexes 2 2 46 4 8 6 Examples 0 46 4 9 General type nodes 2 2 aa 47 4 9 1 Code 2 47 4 9 2 Activation 2 0 47 4 9 3 Function 2 0 47 4 9 4 Relation with other nodes o e 47 4 9 5 Indexes 2 2 48 5 NETWORK 49 5 1 Defininganode aaa 49 5 1 1 Heading 2 2 0 2 ee 49 5 1 2 Code a 50 5 2 Processing the network 2 aa 51 6 INSTRUCTIONS 53 6 1 ASSEMBLE assembles messages in a representative message ooo aa 56 6 2 ASSI assigns values to arrays and multiple nodes 0 0 00 20 e e 57 6 3 COPYMESS makes copies of a Message o e e 58 6 4 CREATE creates a Message aa 59 6 5 DBUPDATE updates a DBASE IV table 0 e 60 6 6 DEASSEMBLE disassembles assembled Messages o o e 2
30. IT EXPO 3 Urgency Round TRIA O 5 7 WRITELN Enter gt Number 3 Urgency Urgency 2 PAUSE Ward R USE 1 Call A Physician REL IL_Ward O_Urgency 0 2 TIME 0_Et gt 5 SENDTO Physician IF NOT EXTREL AND U_Ward gt 0 AND LL EL_Physician lt 4 THEN EXTR IL_Ward FIRST SENDTO Physician IT 10 6 19 RELEASE MANAGES THE MESSAGE RELEASED IN A R TYPE NODE 73 Physician R STAY TRIA 4 6 9 Exit E WRITELN Exit Number 3 gt Urgency Urgency 2 PAUSE INIT TSIM 200 Urgency 3 ACT Entry 0 ACT Call 0 DECL MESSAGES Entry Urgency INTEGER Messages patients are admitted into the Ward if there is room enough Each 10 minutes Call is activated This extracts the first message for which the value of the field Urgency plus a multiple of the waiting time is greater than 5 The extracted message is sent to the node Physician If no message fulfills this condition the first one in the queue is extracted and sent See example 10 GLIDER examples book 6 19 RELEASE manages the message released in a R type node Syntax RELEASE ALL lt associated instruction This instruction is used to manage the messages that abandon the IL of a R type node when the scheduled time is over It is used when the default disposition of the message is not desired The user may program a different procedure in the lt associated instruction gt This m
31. If the value of a is less than 5 the message is taken out of the EL and sent to the EL of the node Carrier jl Here the associate instruction is a Pascal compound instruction between BEGIN END which contains an assignative instruction and an IF instruction containing a GLIDER instruction SENDTO lt field gt is the name of a simple or indexed variable that was declared as a field of a message lt PASCAL instruction gt is a PASCAL instruction structured or simple lt simple PASCAL instruction gt is an assignative instruction lt variable gt lt expression gt or a call to a procedure or a input or output instruction or a GOTO instruction lt structured PASCAL instruction gt is a PASCAL instruction of the type IF CASE WHILE FOR REPEAT or a compound instruction set of instructions delimited by BEGIN END Where a simple PASCAL instruction is allowable it is possible also to put a GLIDER instruction or a GLIDER procedure Example WHILE lt logical expression gt DO BEGIN lt GLIDER instruction gt F lt logical expression gt THEN lt GLIDER instruction gt ELSE lt GLIDER procedure E END There are restrictions that depend on the type of node and of the GLIDER instruction in which the GLIDER instruction or procedure is used Example In the associated instruction of a GLIDER instruction SCAN it is not allowed to use another SCAN instruction Within an associated instruction GLIDER instructions w
32. If the node is activated before the TIME 1999 then an activation is scheduled for the time 1999 and then the message This is the last signal is written 70 CHAPTER 6 INSTRUCTIONS 6 16 OUTG writes variable and array values with titles Syntax OUTG lt variable gt lt file gt lt format gt lt name gt It is used to write values of a single or indexed variable with only one index preceded by a written name The output is always made for the screen e lt variable gt is the name of an INTEGER or REAL variable If it is indexed the lt range gt must follow the lt name gt e lt file gt is a file variable corresponding to a text file that the user must define open and close If lt file gt is omitted then the output is displayed in the screen only e lt format gt is a Pascal format for the data e lt name gt is a string of characters without or It will appear in the written output This instruction can be used in nodes of any type See instruction REPORT 6 20 Example Results A Ttcs MSTL EL_Lock QUTG Ttcs WaitFile 6 2 Mean waiting at lock entrance PAUSE CLOSE WaitFile ENDSIMUL ACT Results 40 ASSIGN WaitFile Waitf Pas REWRITE WaitFile DECL VAR Ttcs REAL WaitPile TEXT If the mean permanence of messages ships queue at the entrance EL of the node Lock was 7 177 then when this instruction is executed the following is written in the screen and in the file Waitf P
33. K G Nock ed Proceed ings de UKSC Conference on Computer Simulation 1990 Brighton 5 7 de Septiembre de 1990 UKSC Publications Burgess Hill England p 69 75 Tonella G Acevedo M Sananes M Domingo C H Hoeger M Ablan Simulation of Ecosystems with GLIDER a Discrete Continuous Simulation Language in M H Hamza ed Applied Modeling and Simulation 1994 Conference Lugano Switzerland June 20 22 Acta Press Anaheim California pp 20 23 Tonella G Domingo C Sananes M Tucci K El Lenguaje GLIDER y la Computaci n Orientada hacia Objeto The GLIDER Language and the OO Programming Asovac XLIII Convenci n Anual 14 19 de Noviembre de 1993 M rida Venezuela Tucci K 1993 GLIDER Orientado hacia Objetos en C Trabajo especial de grado Object Ori ented GLIDER Language in C Thesis Escuela de Ingenier a de Sistemas Universidad de los Andes M rida Venezuela Tutor G Tonella Uzc tegui M 1992 Mecanismos de Manejo de Materiales en GLIDER Basados en SIMAN y SLAM Trabajo especial de grado Material Handling Mechanisms in GLIDER based on SIMAN and SLAM Thesis Escuela de Ingenier a de Sistemas Universidad de los Andes M rida Venezuela Tutor G Tonella Velandia O 1990 Simulaci n Discreta Orientada al Proceso Usando GLIDER Trabajo especial de grado Process Oriented Discrete Simulation using GLIDER Thesis Escuela de Ingenier a de Sistemas Universid
34. Node dependent variables 9 6 Variables depending on user s variables 2 o o e 0 9 7 Variables that may be initialized by the user 0 o e o 9 8 Classes of declarations 9 9 GLIDER or Pascal predefined types ee 9 10 Pascal separators 9 11 GLIDER types of functions GFUNCTIONS o 9 12 GLIDER separators 2 9 13 Operators 2 9 14 GLIDER instructions and procedures 1 9 15 Pascal procedures 9 16 GLIDER functions 2 a 9 17 Pascal functions 9 18 Colors 2 9 19 Pascal constants 9 20 Other reserved words 1 9 21 Types of Node 2 aaa 9 22 Constants 2 aaa vii NN rF Yer TOC CoO Co o viii CONTENTS 10 OPERATION 113 0 1 GLIDER system 3 0 2 Source prograM aoaaa 4 0 3 Operation without environment aooaa e ee 4 0 4 Initial menu 2 4 0 5 Run interactive menu aaa aa 4 0 6 Tracing 2 5 0 7 Statistics 2 aa 5 0 8 Final Menu 2 6 11 DEVELOPMENT OF GLIDER 117 1 1 The GLIDER group 2 2 7 1 2 How to get the GLIDER 2 2 o e 7 1 3 Differences of Version 4 0 July 1996 with the previous versions 8 11 3 1 Introduction ee 8 11 3 2 Version alfa 1988 and beta 1989 2 22 oo ee 8 11 3 3 Version 1 February 1991 2 o o 8 11 3 4 Version 1 1 May 1992 2 2 2 ee 9 11 3 5 Version 2 0 May 1993 and Version 2 1 November 1993
35. The successive values of the index are 1 2 3 etc See instruction NT 6 15 and procedure ACT 7 1 The instruction can be used in any node except of C type Examples 1 Ent I Lathe INO IT UNIF 1 00 1 03 SENDTO Lathe MIN Lathe R 1 4 Messages parts are generated each time the node Ent is activated This happens at intervals taken at random from a uniform distribution between 1 00 and 1 03 The messages go to the less crowded of the four nodes Lathe 2 Signal I IF TIME lt 1999 THEN IT 1999 TIME ELSE WRITELN This is the last signal If the node is activated before the TIME 1999 then an activation is scheduled for the time 1999 and then the message This is the last signal is written 6 14 LOAD IMPORTS A DBASE IV TABLE TO AN ARRAY 69 3 Gate_n1 G 1 3 STATE BEGIN OPEN NOT OPEN IT Interval INO END IF OPEN THEN SENDTO Deposit INO0 INIT ASSI Interval 1 3 17 13 19 Incoming messages are retained each in its gate while the gate is closed and allowed to passed to Deposit when the gate is open The gates are alternatively closed and open The intervals of each state OPEN and NOT OPEN are equal for a gate but are different for the different gates For the first gate they are 17 for the second 13 for the third 19 See examples 1 6 10 13 18 GLIDER examples book 6 14 LOAD imports a DBASE IV table to an array Syntax LOAD lt table gt lt list of fie
36. and just before the beginning of the simulation During the simulation it may be called by pressing the M type It has the following options 10 6 TRACING 115 Continue initialize Statistics read Experiment Write statistics display Future event list Display or skip statistics after each replication Trace Graphic Quit Sasotsmwg o continue the operation or run o initialize Statistics and continue the run o shown the Experimental variables these may be changed by the user to write the standard statistics at the actual state of the run o display Future Event List indicating Node Time Index and Event Parameter to allow to decide if the standard statistics will be displayed or skipped after each replication o put the tracing mode e a fom gs aw O to allow to display a graphic for the results filed with the FILE instruction during the simulation up to the actual time e Q to finish the simulation 10 6 Tracing In the Trace mode the program is executed step by step It may be very useful for inspection and debugging In each event the movements of the messages are reported in detail and the FEL is displayed The steps are advanced pressing any key different of T stop tracing and M call Menu Tracing may be very useful for inspection and debugging Tracing may be called from the Run Interactive Menu from the program TRACE procedure see 7 23 or by pressing the T key during the running If it is c
37. directory the table names must include the path To handle these tables the GLIDER system provides the instructions LOAD UNLOAD see 6 14 6 29 and UPDATE see 7 26 The system declares the following variables N lt table name gt is an integer whose value is the number of records of the table NOM lt name of a simple table gt is a constant array of N_ lt name gt elements that contains the values usu ally key names of the first field of the table For each table integer constants are declared with the names in the first field and successive values 1 2 3 N lt name gt They are useful in the program to refer to records by name The types of the fields may be REAL INTEGER STRING or BOOLEAN Example DBTABLES Pop Group Econ Goods Modat ConsPatt 2 Modat Consp 2 The file Group in the directory Pop may be Fields Group Size Income Savings EmplFrac Records 1 Entrep1 20000 4275000 00 870000 00 1 00 2 Entrep2 300000 1875000 00 322000 00 0 98 3 Entrep3 850000 975000 00 52000 00 0 97 4 Worker1 560000 675000 00 5000 00 0 92 9 SelfEmp 130000 52500 00 10000 00 0 72 This table contains some characteristics of different population groups The system generates the constants N_Group value 9 and the array NOM_Group values Entrep1 Entrep2 gt SelfEmp 1 Entrep2 2 SelfEmp 9 are also defined The constants Entrep1 An array of length 9 is dynamically allocated in memory at r
38. exception of type C nodes See Chapter 4 for a detailed accoun e I Input Generates messages tha to the successor nodes It it It is never activated again e L Line Simulates queue remain in the order indica In First Out or any other of the network if the EL is e G Gate Stops or allows by an event or during the used to change the state o which refers to the node no message flow It has an EL for the retained messages It may scanning of the network if the EL is not empty The instruc of the processing of the different node types enter the simulation process It creates messages and sends them er EL nor IL It may only be activated by an event that refers to y the scanning of the network as neit discipline The messages that enter its EL are passed to its IL where they ed by the code This order may be FIFO First In First Out rogrammed by the user It is activated by an event or during empty LIFO Last the scanning be activated ion STATE the gate is only executed if the node is activated explicitly by an event 1 3 NODES WITH INDEXES e R Resource Simulates resources used by messages A real value called the node capacity is associated to the Resource type node certain quantity o examines the incoming messages the o to the IL the time message is subtracted from the availab ed from the IL and it is sent to to each of them The user can a extrac is sent instr
39. fields that are used by the synchronizing conditions The lt associated instruction gt executed for each successful synchronization may have instructions to change the fields of the messages assigning values to field variables and must have a SENDTO instruction to dispose of the message that represents them Note that this lt associated instruction gt may change the values of variables in the lt logical condition gt and in the lt integer value gt so changing the synchroniza tion conditions for the next group or for a new execution of the SYNCHRONIZE instruction If there was some successful synchronization the variable SYNC is put to TRUE otherwise it is put to FALSE See the instruction ASSEMBLE 6 1 See example 11 GLIDER examples book 6 27 TITLE PUTS TITLE TO AN EXPERIMENT 81 6 27 TITLE puts title to an experiment Syntax TITLE lt string constant It is used to put a title heading to the tables of the standard statistics lt string constant gt isa string constant that may have up to 80 characters The variable TITLE takes the value of this constant and can be used in any writing instruction When the standard statistics are written this title is written at the beginning If no value is assigned to TITLE its default value is BASIC EXPERIMENT This instruction can be used in nodes of any type Example T 272 5 TITLE Experiment with Low Temperature T lt 270 6 28 TSIM sets duratio
40. from other nodes see below are required 4 2 4 Relation with other nodes Identifying of IL with EL The node must have predecessors that can send messages and may have successors that accept messages None of them may be other L type nodes If the only successor is a node of G E R or D type or the general type with EL then the IL of the L node is identified with the EL of the G E D R or general node The multiplicity must be the same These successors will manage automatically the IL of the L type node 4 2 5 Indexes A multiple L type node has multiple ELs and ILs They correspond each other A message in the j EL is passed to the j IL The variable INO has the number of the node being executed 4 2 6 Examples 1 Loi The incoming messages are stored into the ELL When the node is activated they pass to the IL_L in the same order FIFO discipline Queues L 1 5 Gate INO Out IF LL EL_Gate INO gt 4 THEN SENDTO Out ELSE FIFO The messages in the ELs are sent to the corresponding ILs which are the ELs of the Gate node When one of this lists has 4 messages or more the messages are sent to Out OrdQueue L E IF LL IL_OrdQueue gt 15 THEN SENDTO E ELSE IF Priority lt 4 THEN FIFO ELSE ORDER Priority D If the queue is greater than 15 the message is sent to E Otherwise if the field Priority is 4 or more it is ordered by descending Priority otherwise by increasing time of arrival QFiles
41. from the ELs and sent to the successor nodes according to the selection rules indicated by the code 4 5 1 Code It may contain Pascal instructions functions and procedures GLIDER common instructions and proce dures GLIDER functions the GLIDER instructions SELECT SENDTO ASSEMBLE DEASSEMBLE SYNCHRONIZE CREATE and COPYMESS If the node has more than one predecessor the SELECT instruction must be used 4 5 2 Activation It is activated by an event that refers to it or during the scanning of the network if some of the ELs is not empty 4 5 3 Function 1 If there are only one EL each message from the first to the last is extracted from the EL For each message the values of the fields are passed to the field variables and the code is executed The code must have a SENDTO instruction for the message The fields are updated before the message is sent to some list 2 If there are many predecessors there is one EL for each Then a SELECT instruction must be executed that selects messages from some EL and sent them to other nodes See 6 22 for details of this instruction 4 5 4 Relation with other nodes A type D node must have predecessors and successors 4 5 5 Indexes A type D node cannot have indexes 4 5 6 Examples 1 Queuel Queue2 Queue3 ReArrange D Proc1 Proc2 SELECT Queue2 Queue3 Queuel J IF Size 2 THEN SENDTO Proc1 ELSE SENDTO Proc2 The ReArrange node takes J messages from each Queue
42. functions INPOUT TPU I O unit GDINAR TPU Random variates from multivariate distributions GGRAPHIC TPU GLIDER graphic generation RATON TPU Mouse managing unit OBJECTS TPU Mouse management DRIVERS TPU Mouse driver GRAPH TPU Turbo Pascal graphic unit TPC EXE Turbo Pascal procedures GL BAT System monitor TURBO EXE Turbo Pascal compiler if the editor of this program is used EGAVGA BGI Graphic unit The elementary use requires to have the source files in the same directory as the GLIDER files and its presentation is not very sophisticate but may be convenient during the development of large programs because of memory saving in the compilation An environment may be used without those restrictions To use the environment the following units have to be added GLIDERIN EXE Environment unit GLEDIT EXE Editor unit TVGLIDER BAT System monitor TVGL BAT System monitor In this case TURBO EXE and GL BAT are not needed To use graphic input the following units have to be added GLIDERIN EXE Environment unit GLEDIT EXE Editor unit GLIDER GRA Graphic data 113 114 CHAPTER 10 OPERATION TVGLIDER EXE System monitor TVGL BAT System monitor GLISIMB EXE Symbols generator The files TURBO EXE TURBO TPL GRAPH TPL EGA BGI and TPC EXE are files from the package Turbo Pascal V 6 of Borland Corp and are not provided with the GLIDER system The user may contact with authorized dealers to get them 10 2 Source program The source program m
43. gt designs the entry list of the node If the node is of D type with several predecessors it must include the reference to the predecessor between U lt node name gt real its value is the actual quantity of used resource of the R node F lt node name gt real its value is the actual quantity of free resource of the R node M lt node name gt real its value is the total quantity of resource of the R node DT lt node name gt real its value is the integration step that will be used in the indicated C type node The RKF method may change it during the integration process 9 6 Variables depending on user s variables O_ lt variable gt where lt variable gt is a field variable It keeps the value of the alternative field RANDV_ lt frequency array name gt keeps the vector of the random values taken from a random multivariate frequency table VAL_ lt frequency array name gt must be given by the user it must contain the possible values of the random variables corresponding to a multivariate frequency table N_ lt DBASE table name gt is generated when DBASE tables are used it contains the number of records in the table NOML_ lt DBASE table name gt is an array generated when DBASE tables are used It contains the names of the first field of the records in the table name in fields are constants generated when DBASE tables are used They have the names of the first fields in the table and their values are 1 2 3 etc
44. i e an abstract set of data values 1Note that the GLIDER UNIX version is case sensitive see GLIDER UNIX Version Manual 17 18 CHAPTER 2 DECLARATIONS There are types already defined by the GLIDER or Pascal system REAL INTEGER BOOLEAN CONT POINTER etc Each variable in a program must be declared indicating its type With this information the compiler reserve to that variable enough memory space to hold its values that must belong to the type This information also could be used by the compiler to validate that only values belonging to the type are assigned at run time Type identifiers may be referred to in other type declarations in order to define new types A trivial case is to define an alias to an existing type as in the following example Decimal REAL The true usefulness of type declaration is not this mere alias to predefined types but when new structured types have to be defined New types may be defined for convenience of clarity and maintenance otherwise type specifications for variables may be stated directly in variable declarations In the following example the new type Arr5 is declared TYPE ArrS ARRAY 1 5 OF REAL With this new type the programmer can avoid to declare the variables A B z X in this way VAR A B ARRAY 1 5 OF REAL VAR z ARRAY 1 5 OF REAL X ARRAY 1 5 OF REAL Instead the programmer only needs to write VAR A B ArrS
45. intervals gt lt wide of the interval gt lt table name gt is a name declared as table in DECL lt initial value gt is a real value lt number of intervals gt is an integer value lt wide of the interval gt is a real value The system adds lower class for the values below lt initial value gt and an upper class for the values beyond the last class Examples TABLES TABTba 0 0 8 5 0 TFrTemp 32 12 5 TABTba is a frequency table for values from 0 to 40 8 intervals of wide 5 3 5 Values from DBASE IV Tables to Arrays The definition and use of these tables are explained in section 2 8 To store the values in the DBASE IV tables into arrays the instruction LOAD see 6 14 is used This instruction may be used in the NETWORK section too 3 6 Initial Activations Some node must be activated in the INIT section in order to start the simulation run This is made by an ACT procedure see 7 1 Example ACT Hairdresser 5 FOR i 1 TO 5 DO ACT Pump li UNIF O O 0 2 3 7 Interactive Experiments Values assigned to variables in the INIT section can be changed interactively during the simulation or between different runs of the same model To do that the assignation instructions must be included between the words EXPER and ENDEXP The variables in this range are called experimental variables The assignation must be of the form lt identifier gt lt value s gt lt identifier gt corresponds to a ex
46. is executed The preempted message is isposed by a SENDTO instruction that must be in the lt associated instruction gt This instruction may ange the fields of the preempted message before the SENDTO is executed If the option REMA is present e preempted message must have a REAL field called REMA that the user must define and initialize to ero Then the remaining time time that the preempted message would yet remain in the IL is stored nto the field REMA When this message regains the resource with its REMA field different from zero then e time that has to remain in the IL is taken from the REMA instead of using the one indicated by the instruction STAY This value might have previously been changed in the lt associated instruction gt The REMA field is automatically put to zero when the message regains the resource The lt logical expression gt may have global variables local variables field variables of the examined mes sages and 0_ lt fields gt of the occupant message Note that if the removed message has a field REMA and instead of regaining the node from which it was removed it enters another R node the time to remain there would be taken from the REMA and not from the STAY of this node unless the REMA were explicitly put to zero PREEMPTION can only be used in the non RELEASE part of the code of an R type node of capacity 1 and before the STAY instruction acto HE Nato an Example Messages patients
47. is introduced For instance in the case of the DiscoA function if the cursor is in a position between Aa and Bb but near of the Bb and the Y is 7 2 then the point Bb 3 is replaced by the Bb 7 2 The new graph is displayed The user can introduce many changes one by one but the total number of points cannot exceed the maximum declared In the example only up to 2 points can be added to Sp1i1 When 2 is pressed to change to the next graphic the user has the option of storing the new values in a file 6 13 IT schedules next activation of the node Syntax IT lt real expression gt This instruction is used to activate the node in which it appears after an interval time given by the current value of lt real expression gt When executed the value of lt real expression gt is assigned to the variable IT and an event is put in the future event list FEL with e The node number equal to the number in the NETWORK of the node being executed this node number is not used by the programmer who refers to the nodes by its names e An index equal to the current value of INO 1 for single nodes 1 2 3 for successive executions of a multiple node e Even parameter equal to the current value of EVP e Time equal to the current value of TIME lt real expression gt that is to say TIME IT When the node is multiple the instruction may be executed many times In each execution an event is entered in the FEL
48. is used to stop the trace mode that displays a detailed account of the events process messages movements FEL evolution etc useful for debugging This procedure can be used in nodes of any type It has not effect if used in the INIT It must not be executed if the system is displaying a graphic Example IF TIME gt 2000 THEN UNTRACE Tracing mode is suppressed after the time 2000 7 26 UPDATE updates messages fields or field variables Syntax UPDATE MESS O_MESS VAR O_VAR It is used to pass the values of fields from a message in process to the corresponding field variables or alternatively the actual values of the field variables to the corresponding fields of the message in process The argument indicates what has to be updated This procedure can be used only in nodes that process messages code of I G R L D E type general nodes and associate instructions of GLIDER instructions that processes messages Example Inspect G Continue IF pH gt 4 THEN SENDTO Continue ELSE BEGIN Acid TRUE UPDATE MESS END While the EL of Inspect is searching the messages with pH gt 4 are sent to the EL of the Continue node The others are left in the EL of Inspect after putting their Acid field to TRUE Without the UPDATE the field Acid is not changed Chapter 8 FUNCTIONS The GLIDER provides a set of functions that give values of characteristics of the lists some simple mathe matical functions besides
49. made each 0 0625 time units the same part of the graph represents the curve generated in only 3 32 units of time The represented curve appears then stretched twice in the horizontal direction This instruction can be used in nodes of any type Examples 1 ka IT Dta Y SIN 2 PI 2 0 TIME Ag IT Dtg GRAPH O 20 BLACK TIME 7 1 WHITE Y 7 1 Sinus 2 2 LIGHTBLUE INIT TSIM 20 ACT Aa 0 ACT Ag 0 Dtg 0 00753125 Dta 0 0150625 DECL VAR Dta Dtg Y REAL A sinusoidal curve is displayed Note that each calculated point is displayed two times because Dtg is half of Dta As a complete wave takes 2 0 units of time in a screen as the described above each horizontal division is 53 0 00753125 0 39915 and in the 10 divisions 3 9915 enter almost 2 waves 66 CHAPTER 6 INSTRUCTIONS 2 Entrance I IT EXPO TBA ACT Gra 0 Teller R 22 STAY EXPO Tat 2 Exit E ACT Gra 0 Gra A GRAPH O 18000 BLACK TIME 6 O WHITE LL EL_Taq 6 0 Queue 0 100 GREEN The program is a simulation of a simple bank teller and a graphic of the queue is made Each time a client enters or leaves the Teller the Gra node is activated and the length of the queue EL of Teller is put into the graph See examples 14 15 16 17 18 19 GLIDER examples book 6 12 INTI allows interactive change of data Syntax INTI lt variable gt lt format gt lt titl
50. messages O_ lt variables gt o the compared message and any other type of variables and constants If the expression is TRUE both the comparing and compared messages are candidates to be synchronized When all messages are compared the second message in the EL is taken as the new comparing message which is compared with those tha follow it The process is repeated so that all the possible comparisons are made If at any point of the process a number of candidates reach the value expressed by lt integer value then synchronization is successful Then the synchronized messages are taken out of the list one by one and for each synchronized message the lt associated instruction gt is executed The whole process is then repeated to see if another successfu synchronization group of the required size is possible with the remaining messages If the parameter ALL is used there is not limit for the synchronized set If the lt logical expression gt is reduced to the constant TRUE the messages are inconditionally synchro nized up to the specified number or all the messages if ALL is used If there is not successful synchronization at all nothing is done and the lt associated instruction gt is not executed If the function EQUFIELD lt field gt is used instead of the lt logical condition gt messages with the same values on that field are synchronized In all cases it is assumed that all the messages in the EL have the
51. messages and sends them to Debtor When the NUMBER of the messages exceeds the value Enough the sending is stopped and the node Procedure3 is activated 7 6 DEBLOCK suppresses blocking of node Syntax DEBLOCK lt node name gt It is used to finish the block state of a node inhibition of sending messages Its action consists in suppressing the suspended state of the next event activation of the node and to execute the event at the actual time If the node were not blocked nothing is done This procedure can be used in nodes of any type Example Inc T EXPO 1 0 SENDTO FirstProc IF LL EL_FirstProc gt 4 THEN BLOCK Inc FirstProc R RELEASE BEGIN SENDTO SecProc IF LL EL_SecProc gt 5 THEN BLOCK FirstProc END STAY EXPO 5 2 7 7 ENDSIMUL ENDS THE SIMULATION AT THE END OF THE ACTUAL EVENT 87 IF LL EL_FirstProc lt 4 THEN DEBLOCK Inc SecProc R STAY 1 8 IF LL EL_SecProc lt 3 THEN DEBLOCK FirstProc Exit INIT TSIM 25 0 ACTCINC 0 FirstProc 7 F LL EL_FirstProc gt 4 THEN DEBLOCK FirstProc Messages objects arrive the at Inc They must undergo a process in parallel 7 at most and then a sequential process The queues before these processes have a limited capacity and the movement of the messages must be blocked upstream when this quantity is reached Arrivals at Inc are stopped when the queue at FirstProc capacity 7 is equal to 4 After certain time in Fi
52. node of I Input type When executed it generates a message and sends it to the successor node Railroad The message in this example represents a train It has an integer type field called Coaches that indicates the number of coaches In the code of the node after the separator this field is set to a value given by a GLIDER function UNIFI that produces a random integer number in this case between 16 and 20 A new activation of the Depart node is scheduled after an Interval Time of 45 time units The node Railroad is of R Resource type When executed it processes the message and it stores it temporarily in an internal list IL The code sets by means of the GLIDER instruction STAY that the message must remain in the node for a time equal to 25 When the message is released it is sent to the node Destination The node Destination is of E Exit type It takes the message executes the instruction of the code it writes for instance A train arrives at 140 Its length is 17 and it deletes the message See that the value 17 is transported by the message in the variable Coaches After writing the program stops instruction PAUSE and when any key is pressed the simulation continues New trains are generated in Depart each 45 units time then they pass to Railroad and so on The above source program is the input to the compiler system that translates it and runs the simulation The simulation time is not the real proc
53. oe 61 6 7 DOEVENT permits instruction execution only once in the event 62 6 8 DONODE prevents instruction execution during network scanning 62 6 9 EXTR extracts a message from a list o o 2 eo 63 6 10 FILE writes values in a text fille 0 0 o e 63 6 11 GRAPH draws graphics duringarun 2 aa 64 6 12 INTI allows interactive change of data 2 ee 66 6 13 IT schedules next activation ofthe node 2 o ee 68 6 14 LOAD imports a DBASE IV table to an array 2 0 ee 69 6 15 NT schedules a new activation of the node to a future time oaa aa 69 6 16 OUTG writes variable and array values with titles o o 70 6 17 PREEMPTION allows a message to preempt another that is using the resource 71 6 18 REL takes a message out of the IL ofan R type node o o oo e 72 vi 6 19 6 20 6 21 6 22 6 23 6 24 6 25 6 26 6 27 6 28 6 29 6 30 RELEASE manages the message released in a R type node REPORT allows to write an output report in files SCAN scans and processes a list of Messages o o SELECT selects messages from ELs of a D type node SENDTO sends messages in process to lists 2 2 o o STATE controls activations and state of G type node STAY schedules exit time from a R type node o SYNCHRONIZE retains messages in t
54. of PUTFEL Note that there are not reserved words outside these instructions A or D used in the procedures ORDER and SORT to indicate the increasing A or decreasing D order They are not reserved word outside these procedures ALL used in ASSEMBLE or SYNCHRONIZE to indicate that all the elements of the list must be assembled or synchronized ALLNODES used in STATISTICS to ask for statistics of all the nodes EABS absolute error for RKF method of integration ELIM in the ASSEMBLE instruction indicates that all the assembled messages but the representative will be eliminated EQUFIELD in the ASSEMBLE or SYNCHRONIZE to group messages with equal value in a field EREL relative error for RKF method of integration EUL indicates Euler method of integration FIRST in an ASSEMBLE instruction it indicates that the first assembled message will represent the group FIRST or LAST in SENDTO and TRANS to indicate if the sent or transferred message is put at the beginning or ending of the list These words are also used in pointers as indicated in section 2 1 2 FREE in SENDTO to indicate the first free in a multiple node LABEL used in the heading of a node to declare labels for the node MESS used in UPDATE to update the fields of the message being processed MIN in SENDTO to indicate the less occupied in a multiple node MAXSEL in SELECT to indicate the maximum of messages to be selected in the next selection attempt 112 CHAP
55. of data in a text file The user may also use the instructions of the Pascal language to write files FILE instruction relieves the user from declare assign open and close the files lt file name gt is a valid name of file If the file exists it is overwritten by the new data If it does not then it is created and opened at the beginning of the simulation and closed at the end of the simulation lt list of expression format gt is a list of expressions as the lists in WRITE or WRITELN in Pascal Expressions must not be broken in different lines Generated text files have the following structure e A heading of strings each with the expressions in the list one each line The format is omitted e A symbol 1 to indicate the end of the heading 64 CHAPTER 6 INSTRUCTIONS e The values recorded one line each execution of a FILE instruction e If there are replications then for the second third etc replication the list of expressions is omitted and instead of 1 the number of the replication 2 3 etc precedes the data of each replication Thus only one file is made with all the data generated by the replications The system introduces an extra blank space between contiguous values If many FILE instructions write in the same file the order of the lines in the file is the order of the executions If the file is to be used with the Graphic option the list would consist of simple real variables without format T
56. of the lt real variable gt is classified to define to which frequency class of the table it belongs and one is added to the count of this class The frequency classes and a histogram are shown when a display of the standard statistics is produced This is always done at the end of the simulation but also can be done interactively at any moment of the run or by the program using the STAT instruction See 2 10 and 10 7 for declaration and description of the standard statistics This procedure can be used in nodes of any type Example Ent_People I IT EXP0 32 4 L_Queue LL EL_Couter TAB L_Queue TabQue L_Queue LL EL_Counter TAB L_Queue TabQue NIT 7 23 TRACE STARTS THE TRACING 95 DECL VAR L_Queue REAL TABLES L_Queue TabQueue Messages people enter the system and queue at the node Counter not shown They exit at node Exit When these events happen the queue changes The length of the queue is passed to a real variable L_Queue and is registered at the frequency table TabQueue This table has 10 classes intervals of length 4 and starts at the value 0 7 23 TRACE starts the tracing Syntax TRACE It is used to put the trace mode that displays a detailed account of the events process messages movements FEL evolution etc useful for debugging It must not be executed if the system is displaying a graphic This procedure can be used in nodes of any type It has not effect if used in the INIT
57. processing SET To declare as new type the power set of an ordinal type called the base type The power set of the base type is the set of all its subsets including the empty set The cardinality i e the number of elements of the base type has to be not greater than 256 This restriction excludes as base type the ordinal types INTEGER LONGINT and WORD Values of a set type are sets that can be operated with the set operators Also are defined the logical binary IN operator relating a base type value with a SET type value and the set constructor using the characters and as delimiters The empty set is the expression The syntax is lt name gt SET OF lt ordered type gt Examples TYPE COLOR SET OF Red Yellow Green Brown VAR Paint Hue Dye COLOR Digit SET OF O 9 Paint can take as value any of the 16 subsets of the elements indicated in the declaration of its type including the empty and the total set Digit may take as value any subset of the digits One assignation of value may be Digit 0 1 2 In this case the expression 2 IN Digit Is true 4 IN Digit is false If Paint Red Yellow and Hue Red Green Yellow then Dye Hue Paint Brown would have the elements Red and Brown 22 CHAPTER 2 DECLARATIONS 2 1 4 String types To declare as new type a succession of characters of variable length ranging from 0 to a maximum declared The syntax is lt ty
58. represented by this name If the value is transferred to other variable then both will differ without knowledge of the user because the solving algorithm changes the variable TIME without updating the user s variable 4 7 2 Activation The node is first activated from the INIT section or from other node Then the solving process starts During the execution the node activates itself at each integration step This activations does not produce scanning of the network They may be interrupted and continued when the node is deactivated or activated by the instructions ACT and DEACT 4 7 3 Function 1 Ina C type node one or more systems of differential equations are solved The whole code is executed at each integration path and the execution of the events of all the program interleaved with those of the differential equations On the other hand the C node can generate events and messages by conditions that may depend on the values computed for the differential equations Thus a symbiosis of continuous and discrete simulation is complete 2 As the self activations of the node do not produce scanning of the network all actions in the network that depend on the values computed by the differential equations must be explicitly programmed in the node see examples below The C type node can be called to be executed at any time from any other node The calling instruction is lt name of the C node gt 0 When this happens the node solves
59. restricts the array declaration syntax of index types to subranges whereas Pascal accepts any ordinal type specification The first index can take values from nil to nfl the second from ni2 to nf2 etc The values of the indexes may be of type INTEGER LONGINT BYTE WORD or enumerated type Examples TYPE Vec ARRAY 5 5 OF REAL VAR X Z Vec Mat ARRAY 1 3 2 3 OF CHAR ShirtPrice ARRAY Small XLarge Cotton Silk OF REAL Vec will be a simple array with index values from 5 to 5 Mat a two index array the first from 1 to 3 the second from 2 to 3 The successive elements in the memory will be Mat 1 2 Mat 1 3 Mat 2 2 Mat 2 3 Mat 3 2 Mat 3 3 The rightmost indexes change first ShirtPrice has as indexes values of an enumerated type that have to be defined previously for example with declarations Size Small Medium Large XLarge Fabric Dacron Cotton Flax Silk e RECORD To declare as new type a succession of components or fields each of them of a declared type Thus the field components of a record may be of different types whereas array components are of the same type The syntax of the declaration is lt type identifier gt RECORD lt list of field declarations gt END The field declarations of the list are separated by Examples PShip Ship Ship RECORD Draft Displacement REAL LoadClass ARRAY 1 5 Pfs PShip Pointer to the next ship END
60. tables The user may also declare as new simple types e Enumerated types ordered sets of identifiers The syntax is lt type identifier gt lt list of identifiers gt Example Size Small Medium Large Extralarge Medium is then a constant of type Size Order relations hold for instance Small lt Large is true ord Large has the value 3 e Subrange types subranges of any ordered type INTEGER LONGINT CHAR WORD BYTE and user s defined enumerated types The syntax is lt type identifier gt lt initial value gt lt final value gt Examples VAR CapLetter 4 2 LargeSizes Large ExtraLarge TYPE Digits 0 9 2 1 2 Pointer types e POINTER Is a general pointer type Variables of this type may be used as temporal storage for pointer values i e values of addresses of program elements variables functions or procedures in the space of memory locations at run time Example VAR Ppa POINTER e Typed pointers They are specific pointer types Variables of specific pointer type may hold values of addresses of program elements of the specified type in the space of memory locations at run time The syntax of the declaration is lt pointer type identifier gt lt type identifier gt It defines a new pointer type to element values of the identifier type which may be a simple or structured type Example Ptra Train Train Record Engine STRING 6 Wagon ARRAY 1
61. the beginning to the end and for each message the lt associated instruction gt is executed The fields of the message are in the 0_ lt fields gt If the lt associated instruction gt executes a SENDTO the 0_ lt fields gt are passed to the message which is extracted from the assemble list and it is sent to the indicated node If no sending is occured the 0_ lt fields gt that may have been changed are passed to the message and this remains in the assemble list The representant message see instruction ASSEMBLE 6 1 may be disposed before or after the execution of the DEASSEMBLE instruction DEASSEMBLE may be used in nodes of G D E and of general type and in the RELEASE instruction of an R node Examples 1 Travel R RELEASE DEASSEMBLE SENDTO Depot Typ1 SENDTO Parking STAY Travel_Time Weather After remaining in the IL of the node Travel for a time that is a function of the variable Weather the representants are released and their assembled lists are disassembled Messages of the assembled list transported items are sent to the different nodes Depot according the value of the field Typ the representant transporter is sent to the node Parking 2 Bus_Stop Exit_Pas E DEASSEMBLE BEGIN By_Bus TRUE N_Arr N 1 IF By_Air THEN SENDTO Airport ELSE SENDTO RailRoad END Messages passengers of the assembled list of the first message bus are marked in the field By_Air to TRUE and a number of arrival is
62. the case the SENDTO is in an lt associated instruction gt the sent message is In ASSEMBLE the representant of the assembled messages In COPYMESS each copy made of the original message In CREATE the created message In DEASSEMBLE each message that is taken off the assembled list In EXTR the extracted message In PREEMPTION the removed preempted message In REL the extracted from the IL In RELEASE the extracted from the IL In SCAN the actually examined message In SELECT each selected message In SYNCHRONIZE each synchronized message SENDTO can be used in type G L I D E A and general type nodes and in the lt associated instruction gt of the GLIDER instructions indicated above such as in the RELEASE instruc tion The nodes referred to inthe SENDTO instruction must be explicitly indicated in the list of successors unless there are only one successor and it is implicitly defined as such by being the following in the program If the successor is a multiple node the user have three alternatives to send a message to its ELs To indicate the desired index in the node specified in the SENDTO To use the reserved word MIN as index In this case the message is sent to the first node for which the sum lt Length of the EL gt lt quantity of used resource gt is the minimum That means the less engaged node of the array To use the reserved word FREE as index In this case the message is sen
63. the piers it is sent to the ifferent pier each may receive is assigned in the INIT section as said above he quantity of resource used by each message that all the ships use the same space equal to ribution for different types of ships the mean he type of after passing the channel the code and destroys the message a GLIDER defined field of the time TIME GT is the total TabTSys This table was declared in the DECL section The parameters of the table are assigned in INIT In this case the initial va histogram is s ue of the table is 0 and there will be 15 intervals of length 5 The table and a own when requested by the user The instruction INTI in the INIT section allows for interactive change of the values of TPier for different experiments 1 5 2 Standard Statistics Port Basic experiment Time 1200 00 Time Stat 1200 00 Replication 1 23 2 1996 21h 20m 7s 1 5 EXAMPLE 2 PORT WITH THREE TYPES OF PIERS Elapsed time ENTRANCE 1 Gen CONTROL 1 EL CHANNEL DEPARTURE 1 EL Time in System Mean Var Ind U_CHANNEL U_PIER U_PIER U_PIER Oh Om 27 585 Nod Ind Ant Li Ent Lgth UNA 291 291 579 579 155 155 100 100 36 36 288 oo FPFOOON SG Max Mean 9 0 93442 o 0 03409 0 09650 es 0 11652 2 53706 632 2 0 99144 0 53564 0 83015 PWN Pw 1 0 0 25 0310 Dev Mean t Dev t 0 09650 0 29528 2 53706 1 30822 0 99144 0 793
64. the v is also Window he IL simple c successo is now activated by the scanning process with is IL empty So it searches again to see if there are in EL othe Otherwi The node Exit is of E type when the type is not declared the by the fi by the e he EL of the node T IL is empty searc or a message having an exit time equal to the time of is EL represents the queue of patrons at the window The IL represents the patron rved When the node Window is activated during the scanning process of the network and happen because the node Entry started such a scanning the procedure of the node type R if the es the EL If it is empty nothing is further done If it has messages the procedure takes message to pass it to the IL If the IL was occupied it contains a message representing a patron e resource the incoming message remains in the EL When a message is introduced in the IL that at a new service starts Then the GLIDER system schedules an event of end of service That is activation of the node Window at a time equal to the actual value of TIME plus the value assigned ariable STAY In this case the value is taken at random from a gaussian distribution That time ept in a field of the message as its exit time When that future activation takes place the node is again activated but now by the event that refers to it In this case the procedure searches he event that is the actual time In this he ow he rocess as th
65. those provided by the Pascal language and some random functions that generate random variates These functions can be used in any place in the INIT and NETWORK sections in which a variable of the same type is allowed Here is a list of these functions an the returned values 1 LL number of messages of a list 2 MAXL maximum number of messages of a list 3 MINL minimum number of messages of a list 4 MEDL mean length of a list 5 DMEDL deviation of the mean length of a list 6 MSTL mean time of staying time in a list 7 DMSTL deviation of the mean time of staying time in a list 8 TFREE time that the list was free 9 ENTR number of entries in a list 0 MAX maximum value of a pair of real expressions 1 MAXI maximum value of a pair of integer expressions 2 MIN minimum value of a pair of real expressions 3 MINI minimum value of a pair of integer expressions 4 MODUL rest from dividing two real expressions 5 BER random value from a Bernoulli distribution 6 BETA random value from a Beta distribution 7 BIN random value from a Binomial distribution 8 ERLG random value from an Erlang distribution 9 EXPO random value from an Exponential distribution 20 GAMMA random value from a Gamma distribution 21 GAUSS random positive value from a Normal distribution 97 98 CHAPTER 8 FUNCTIONS 22 LOGNORM random value from a Lognormal distribution 23 NORM random value from a Normal distribution 24 POI
66. time delay in loading and transport is taken into account When this process finishes the message is sent to ProcLoad to process the actual load If the heap is not empty a copy is sent to a node Return to account for the delay to return near the heap Otherwise the copy is sent to Command that decides about new command messages to remove heaps In the Return node the message is delayed a time for the return and then sent to the Crane again before other commands to continue the heap removal Notice the condition IF F_Crane 0 to avoid execution of instructions without transfer of the message to the IL 7 11 LIFO puts the message at the beginning of the IL of a L type node Syntax LIFO It is used to pass a message from the EL to the beginning of the IL ofa L type node The first message in the EL of the L type node is passed to the beginning of the IL The IL is formed in the order reverse to that of arrival LIFO order It may be used only in L type nodes Example Cellar L FIFO Messages coming to Cellar are put in the EL in order reverse to the arrival order LIFO order 7 12 MENU calls the Run Interactive Menu Syntax 90 CHAPTER 7 PROCEDURES MENU It is used to call the Run Interactive Menu see 10 5 This procedure can be used in nodes of any type 7 13 METHOD sets the method of integration in a C type node Syntax METHOD lt RKF gt lt EUL gt lt RK4 gt 1 It is used in a type C n
67. variable SYNC is put to TRUE otherwise it is put to FALSE 6 26 this lt associated E ELIM 3 EQUFIELD Typed tatus Finished SENDTO Paint END equal values in the field Typed are sought for When a group is found the first message is marked as Finished in its field Status and sent to the EL of the node Paint The other two messages of the grou 2 FormGroups G ASSE BEGI IF N The the value of the field Age gt 10 field groups of this size are formed b node is of G type the process i the EL When an attempt to fo ASSEMBLE instruction and the size of the sought grou until groups of size two are sou Leader and sent to the node Tour keeping a poin are deleted The node Unite_Parts is of the common type MBLE FIRST N Age gt 10 AND O_Age gt 10 N Leader TRUE SENDTO Tour END OT SYNC AND N gt 2 THEN N N 4 rocess attempts to form groups of size N whose value was defined elsewhere of messages with the first one is marked putting to TRUE its to the assembled messages All the possible y the ASSEMBLE instruction When the instruction is finished as the s repeated if the EL is not empty starting again for the first message of rm groups is not successful the variable SYNC is put to FALSE by the is reduced by one The process is repeated When a group is found ght for 6 2 ASSI assigns values to arrays and multiple nodes Syntax 58 CHAPTER 6 INSTRUCTIONS ASSI
68. what are the adequate activations Problems of this type may occur also in ordinary programming but they are more easily avoided because the order of execution is more explicit for the programmer Another consequence of the scanning of the network is that some instruction may be unnecessarily executed many times This may produce waste of time or erroneous results Example Gate G IF Class Good OR LL EL_Gate gt 3 SENDTO Market END Insp Insp 1 The EL of Gate is examined and if the condition is fulfilled the messages are sent to Market In Insp it is supposed to take into account the number of inspected messages However as the EL may not be exhausted in one activation of the node up to three not Good items may remain in a further activation in the same event the remaining messages are inspected again given a false value of the inspected number The user can avoid the effects of the repeated execution of some or all the instructions of a node using the instructions DONODE and DOEVENT see 6 7 and 6 8 Example Gate G IF Class Good OR LL EL_Gate gt 3 SENDTO Market DOEVENT Insp Insp 1 In this case the instruction Insp Insp 1 is executed only the first time the node is activated The type C nodes activate themselves automatically each integration interval For example if a message must be sent when Level reaches or exceeds 123 0 the program Tank C Level Inflow K Level
69. 0 1 When a message in the EL of the node is processed and a initial value was assigned to j that is the state of the RandomSend node then a random value between 0 and 1 is assigned to u The WHILE cycle searches from top to bottom in the column j for the last row for which u lt Tran i j So the probability of a certain final value of iis the value of T i j That i value is assigned to j The next change of state is made after a time given in the Perm array Messages arriving during this time interval are sent to Destination j So the destination varies according to states that change at random with the transition probabilities given by the matrix T 6 25 STAY schedules exit time from a R type node Syntax STAY lt real expression gt It is used to assign value to the time that a processed message will remains in the IL of a R type node It is only used in a R type node When executed a message enters the IL an event is scheduled in the future to extract this message More exactly an event element is introduced in the FEL that refers to the R type node to be executed at a time 80 CHAPTER 6 INSTRUCTIONS TIME STAY with the assigned value for the STAY The index of the event is taken from the variable INO and the event parameter will be the actual value of the variable IEV If the node contains a PREEMPTION instruction with a REMA parameter the message must have a REMA field The system checks the value of this field If it
70. 1 Money 2 and NumberTrans will be displayed Chapter 3 INITIALIZATIONS In the INIT section of a GLIDER program the user puts the instructions to give the particular values to the data to be used in a simulation run These are assignation for 1 Initial values to simple variables an arrays Initial capacity values to R type nodes Values of functions given by pairs of values Values of frequency tables parameters Values from DBASE IV tables to arrays Initial activation of nodes nyane S N Experimental variables 3 1 Initial Values to Simple Variables and Arrays For simple or indexed variables assignative instructions are used Examples Pressure 15 Temp 275 0 R 8 2056E 2 n 4 CH Y Volume n R Temp Pressure FOR i 1 TO 7 DO Concentr i Fconc Fconc may be a user s defined function a FREQ type function etc For arrays the ASSI instruction see 6 2 may be used Examples ASSI Conc 1 7 0 22 0 33 0 42 0 11 0 13 0 17 0 66 ASSI OrigDest 1 4 1 4 0 4 0 2 0 3 0 1 0 1 0 6 0 1 0 2 0 2 0 4 0 1 0 3 0 2 0 2 0 5 0 1 Reading from keyboard or files may be used Examples WRITE Relative Humidity READLN RelHum i 1 WHILE NOT EOF AbsRateFile DO BEGIN READLN AbsRateFile AbsRate i i i 1 END 29 30 CHAPTER 3 INITIALIZATIONS 3 2 Initial Capacity Values to R Type Nodes For simple or indexed R nodes an as
71. 57 0 83015 0 37550 Table TABTSYS of variable TINSYS Interval lt 0 0 00 lt 5 5 00 lt 10 10 00 lt 15 15 00 lt 20 20 00 lt 25 25 00 lt 30 30 00 lt 35 35 00 lt 40 40 00 lt 45 45 00 lt 50 50 00 lt 55 55 00 lt 60 60 00 lt 65 65 00 lt 70 70 00 lt 75 gt 75 Total 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Freq ND o OoMNNOoOo RON w NRrPOrRKENNWHD a 288 Rel Fr 000 000 007 O56 4 EEK O17 010 007 007 003 003 000 003 OS Zoo 000 2400000000000000000 0000knRo Dev 26150 27533 29528 44114 30822 07922 79357 87107 37550 0 0 21 6358 Max 1 00000 4 00000 2 00000 1 00000 MaxSt MeanSt 101 587 3 80141 1 00466 0 07064 0 20000 0 19965 18 2005 0 90207 24 4311 19 3037 3 22191 0 07579 15 7321 11 7546 89 3944 17 8548 33 6624 27 9559 0 0 0 0 Max 141 692 Min Mean v 0 50000 69481 17000 50704 i 0 0 0 0 2 0 0 1 0 00 Dev 11 4577 0 16318 0 01175 07138 60884 40935 26446 25 6300 0 0 3 3 0 2 0 0 Min Dev v 0 50000 1 07103 0 68637 0 49995 T Free 628 1176 1084 1107 109 1192 383 807 203 1200 No 0 O0O0msnNnN0D 0 9 42319 Actual 0 0 2 00000 0 0 1 00000 28 dada dada EEEE EE EEE ET EEE EEE EE EEE EEE EE ZA adolfo EEE EEE EET ET EEE EEE P
72. 99 8 5 DMEDL deviation of the mean length of a list Syntax DMEDL lt list name gt Returns the value REAL of the standard deviation of the mean of the length as a function of time for the list EL or IL indicated in lt list name gt Example WRITELN Coefficient of variation for queue DMEDL EL_Office MEDL EL_Office 7 3 8 6 MSTL mean waiting time in a list Syntax MSTL lt list name gt Returns the value REAL of the mean of the waiting time of the messages that left the list EL or IL indicated in lt list name gt Example IF MSTL EL_Park 1 lt MSTL Park_ 2 THEN SENDTO Park 1 ELSE SENDTO Park 2 8 7 DMSTL deviation of mean waiting time in a list Syntax DMSTL lt list name gt Returns the value REAL of the standard deviation of the mean of the waiting time of the messages that left the list EL or IL indicated in lt list name gt Example IF DMSTL EL_Door_A gt DMSTL Door_B THEN Ch gt A ELSE Ch gt B WRITELN Queue in door Ch had greater fluctuation 8 8 TFREE time that the list was free Syntax TFREE lt list name gt Returns the value REAL of total time in which the list EL or IL indicated in lt list name gt was void Example Access I A B IT UNIF 5 7 IF BER Prob_A THEN SENDTO A ELSE SENDTO B Prob_A 1 TFREE EL_A 1 TFREEC EL_A 1 TFREE EL_A 100 CHAPTER 8 FUNCTIONS 8 9 ENTR number o
73. ARD Procedures BLOCK and DEBLOCK Procedures BEGINSCAN and MENU Elimination of the instructions GO GOALL STOP STOPALL Change in the instruction SENDTO Elimination of the procedure AGRE Elimination of resources with size 0 and introduction of resources with size MAXREAL New version of the manual in Spanish New default statistics First short version of the manual in English Change of instruction COPY to COPYMESS A new version of the GLIDER environment 120 CHAPTER 11 DEVELOPMENT OF GLIDER 11 3 7 Version 4 0 July 1996 It includes e A complete new version of the manual in English e A correction of some bugs and a complete review of all the commands with minor changes e A version for the Unix operating system e Elimination of GPOINTER declaration Bibliography 1 Acosta Castillo C A 1991 Editor Sint ctico del Lenguaje de Simulaci n GLIDER Documento de Dise o Trabajo especial de grado Syntactic Editor for GLIDER Simulation Language Thesis Escuela de Ingenier a de Sistemas Universidad de los Andes M rida Venezuela Tutor G Tonella 2 Acosta Castillo C A 1991 Ambiente Integrado del GLIDER Manual del Usuario Versi n 1 0 Integrated Environment of GLIDER User s Manual Version 1 CESIMO Technical Report IT 9101 Universidad de los Andes M rida Venezuela March 1991 3 D az E 1993 Modelo en GLIDER para el Central Azucarero de R o Turbio Trabajo especial
74. CESIMO WORKING PAPER IT 9608 GLIDER Reference Manual Version 4 0 for MS DOS operating system 1991 1996 CESIMO amp IEAC Universidad de Los Andes CESIMO WORKING PAPER IT 9608 GLIDER Reference Manual Version 4 0 for MS DOS operating system August 1996 1991 1996 CESIMO amp IEAC Universidad de Los Andes CESIMO Simulation and Modeling Research Center Universidad de los Andes M rida Venezuela phone 58 74 402879 fax 58 74 402872 email cesimo ula ve ii Contents 1 INTRODUCTION of the GLIDER Simulation Language 1 1 1 2 1 3 1 4 1 5 1 6 Characteristics 1 Example of discrete simulation 1 2 Example of con Types of nodes Nodes with in Example 1 Simple Serving System AL 4 2 Trace of the operations 4 3 Standard Statisti Example 2 Port with Three Types of Piers 5 1 Remarks about the program 5 2 Standard Statisti Compilation Details exes Description of the process 2 DECLARATIONS 2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 2 9 2 10 STATISTICS 3 1 3 2 3 3 3 4 TYPE 2 1 1 2 1 2 2 1 3 2 1 4 2 1 5 Procedural types CONST Simple types Pointer types Structured types String types 2 NODES MESSAGES GFUNCTIONS TABLES DBTABLES PROCEDURES INITIALIZATIONS Initial Values to Simple Variables and Arrays Initial Capacity Values to R Type Nodes Values to Functions Given by Pairs of Values Values to Frequency Table P
75. E RELEEEEEEEEEEEEE EEE EE EEE EEE ET EEE EEE EE E 080 ERR REE ERE 15 16 CHAPTER 1 INTRODUCTION 1 6 Compilation Details Although compiling details are transparent to users some information may be useful The source program is written in a file It is read and processed by the GLIDER compiler that translates it to several units of Pascal code The program code of the nodes are translated into procedures The messages are translated into records that may have different structures according to the fields declared in the MESSAGES declarations The actual items that are in the ELs and ILs are fixed structure records for all kinds of messages called indicators of messages They have pointers to the true messages and some auxiliary fields number of the message original node name and pointer to the following indicator in the list or NIL if it is the last The program so produced by the GLIDER compiler may be then compiled and executed by a Pascal system Chapter 2 DECLARATIONS A GLIDER program uses variables of different types GLIDER includes definitions for certain types vari ables constants functions and procedures required for general processing Others are also system defined to meet special requirements of particular models Besides users may define types variables constants functions and procedures needed to program their models Other instances of language elements may also be defined messages functions given by pairs
76. EXIT 1 LL 1 TIME DELETED MESS 3 GENERATED IN ENTRY AT 0 888 NODE WINDOW 1 EXA MESS 5 GEN ENTRY Future Event List at Time 11 858 NODE ENTRY T 11 890 IND 1 EVP 0 NODE WINDOW T 16 019 IND 1 EVP 0 EVENT 1 IEV LOR RRR KKK KKKKKD DDD DD gt gt gt gt gt gt DD TIME NODE ENTRY 1 7 7 11 11 11 11 11 734 734 734 734 734 734 917 917 858 858 858 858 858 858 3890 11 12 CHAPTER 1 INTRODUCTION 1 4 3 Standard Statistics When required by the declaration STATISTICS the GLIDER produces an output with statistics of nodes and variables This statistics are always displayed at the end of the simulation but they can be shown at any time during the run by program indication or by an operator interruption that calls the Run Interactive Menu Statistics for one run of the simulation example follows Basic Experiment Time 1000 00 Time Stat 1000 00 Replication 1 22 2 1996 11h 53m 275 Elapsed time Oh Om 3 28 Nod Ind Ant Li Ent Lgth Max Mean Dev MaxSt MeanSt Dev T Free ENTRY 1 Gen 287 WINDOW 1 EL 287 23 31 19 6351 7 42638 121 549 64 6315 33 9571 0 4 IL 264 1 1 1 00000 0 0 5 89579 3 78773 0 78256 0 0 EXIT 1 EL 263 0 1 0 0 0 0 0 0 0 0 0 0 1000 0 Time in System Mean 73 7248 Dev 29 8822 Max 124 650 Min 4 40897 Var Ind Mean t Dev t Max Min Mean v Dev v Actual U_WINDOW 1 1 00000 0 0 1 00000 0 0 0 50095 0 50000 1 00000 The title of the experiment is b
77. EXIT TIME FROM A R TYPE NODE 79 1 Portal G STATE IF p open THEN BEGIN p closed IT 10 END ELSE BEGIN p open IT 20 END IF p open THEN SENDTO Castle ELSE STOPSCAN Messages Knights that arrived at Portal only pass to Castle if the value of p is open Due to the STOPSCAN only one message of the EL the first one is considered if p is closed The STATE instruction works in an independent way The variable p is put closed by 10 units of time and open by 20 units of time alternatively To start this process the node Portal must be firstly activated from other part of the program The part of the code outside the lt associated instruction gt of the STATE the second IF instruction is executed each time the node Portal is activated during the scanning of the network if the EL is not empty 2 RandomSend G STATE BEGIN j 1 u UNIF O 1 WHILE tran i j lt u DO i i 1 j i IT perm i END SENDTO Destination j tran is a matrix with accumulated values of a probability distribution in each column It can for instance be defined by ASSI tran 1 3 1 3 0 1 0 4 0 2 0 7 0 9 0 6 1 0 1 0 1 0 This corresponds to the transition probability matrix T 4 u ooo ES 1 6 3 ooo 4 0 5 0 1 0 If it is j 2 the probability of transition to 1 is 0 4 to 2 is 0 5 to 3 is 0 1 See that Tran 1 2 0 4 Tran 2 2 0 4 0 5 Tran 3 2 0 4 0 5
78. Example IF EL_Shop gt 10 THEN TRACE ELSE IF EL_Shop lt 5 THEN UNTRACE If the queue in Shop is greater than 10 the trace starts when the queue decreases and becomes 5 or less the trace is stopped 7 24 TRANS transfers a message Syntax TRANS lt origin list gt FIRST LASTI lt origin pointer gt A IB I lt destination list gt FIRST LAST lt destination pointer gt It is used to transfer a message from one position in a list to another position in another or the same list e lt origin list gt is the name of the list from which the message is taken e FIRST LAST lt origin pointer gt indicates the position of the message to be sent e lt destination list gt is the name of the list to which the message has to be sent e A B is only used if a lt destination pointer gt follows It is used to indicate if the message as to be put after or before the position indicated by the pointer e FIRST LAST lt destination pointer gt indicates the position to which the message has to be sent This procedure can be used in nodes of any type Example SCAN IL_Depot P_Item IF Cost gt 500 THEN STOPSCAN TRANS IL_Depot P_Item B NewProc P_Rear After a scan in IL of node Dept the first message with Cost gt 500 is pointed Then it is transferred to the EL of node NewProc before the element pointed by P_Rear 96 CHAPTER 7 PROCEDURES 7 25 UNTRACE stops the tracing Syntax UNTRACE It
79. FEntry 0 0 0 4 14000 0 0 6 27000 0 0 3 52000 0 0 2 86900 0 0 4 Alarm FALSE Recovering FALSE Send TRUE DECL VAR KQLevel KOLevel TravelTime REAL Level CONT Alarm Send Recovering BOOLEAN MESSAGES TankCar VTankCar REAL GFUNCTIONS FEntry POLYG REAL REAL 6 STATISTICS ALLNODES END 2 TEST OF DIFFERENTIAL EQUATIONS Computed known solutions of some systems of differential equations NETWORI Clos Y R Y SIN T X 1 0 1 X 1 LINEAR SLOPE 0 1 X 2 0 2 X 1 LINEAR SLOPE 0 2x R Y R COS T X3 X 1 X 3 PARABOLA Zz R Z SEN T C2 Z 0 15 X 1 LINEAR SLOPE 0 01 X 1 X 31 X 1 COS T x X3 X 1 X 3 SIN T Ss Z 2 X 1 PARABOLAx Grai A IT 0 0625 GRAPH O 100 BLACK TIME 6 1 WHITE Y 6 2 SEN 1 1 RED R 6 2 COS 1 1 GREEN X 1 6 2 Lp01 10 10 YELLOW X 2 6 2 Lp02 10 10 MAGENTA X 3 6 2 Parab1 10 10 LIGHTGREEN Z 6 2 MSen 2 2 BLUE 46 CHAPTER 4 SYSTEM PREDEFINED NODES Gra2 A IT 0 0625 GRAPH O 100 BLACK TIME 6 1 WHITE X 1 6 2 Lp01 10 10 YELLOW X 3 6 2 Parab1 10 10 LIGHTGREEN Z 6 2 MSen 2 2 BLUE S 6 2 Parab2 10 10 BROWN INIT TSIM 100 Tc 0 INTI Tc 3 Tc O FOR C1 1 FOR C2 IF Tc O THEN BEGIN ACT C1 0 ACT Grat 0 END ELSE BEGIN ACT C2 0
80. IL of this is the same of the EL of the G type node If the G is multiple the predecessor L must have the same multiplicity 4 3 5 Indexes A multiple G type node has as many EL as its multiplicity When it is activated all the nodes are executed sequentially The variable INO has the number of the node being executed 38 CHAPTER 4 SYSTEM PREDEFINED NODES 4 3 6 Examples 1 Gi When activated this node scans the EL and nothing is made From other nodes it is possible to extract and modify the messages of its EL 2 Inspect G Sale Repair IF Defect THEN BEGIN STOPSCAN SENDTO Repair END ELSE SENDTO Sale If the boolean field Defect of the message article is TRUE the examination of the list stops and the message is sent to Repair Otherwise it is sent to Sale In the first case the scan is stopped will continue in the next activation during the same event in the second case the scan continues Note that the STOPSCAN must be used only if it is necessary see next example because it increases the processing time by repeating the scanning of the network 3 Semaf G Street STATE BEGIN Green NOT Green IT 25 END IF LL IL_Street lt 20 AND Green THEN SENDTO Street STOPSCAN Each 25 units of time the boolean variable Green changes its true value The node allows the messages cars to pass if Green is true and the IL of the successor node Street has less than 20 messages When a message passes the scanning
81. ING 20 Recep_Time Control_Time Ship_Time REAL Messages orders produced by Prod_Order are sent to Control to be inspected and then sent to Ship_Order For each order sent to Ship_Order a message of the same structure is created an sent to File_Order with the value of the control time in the field Control_Time 6 5 DBUPDATE updates a DBASE IV table Syntax DBUPDATE lt source table gt lt destination table gt lt list of fields gt This instruction is used to update a DBASE IV table lt destination table gt with the values of fields that were previously loaded in an array from another table lt source table gt Both tables must have the same structure Eventually they may be the same table Most frequently DBUPDATE is used in this case fields of a table are imported by means of a LOAD instruction into arrays in the running program these arrays are changed by the simulation process Then the new values may be returned by means of the DBUPDATE instruction to the same table or to another table that may be void or filled with any number of records The lt list of fields gt indicates what fields have to be updated into the lt destination table gt After the execution of the DBUPDATE the lt destination table gt remains with the same number of records than the lt source table gt See declaration DBTABLE 2 8 and instruction LOAD 6 14 UPDATE can be used in any type of node Example LOAD Student1 Nam
82. INO IT EXPO MeanArrT INO BactConc GAMMA MBac INO 0 2 MBac INO SENDTO LabSecLINO LabSec R 1 7 STAY 0 031 BactConc INIT TSIM 7200 ASSI MeanArrT 1 7 3 2 3 6 3 3 3 8 4 0 3 97 3 5 FOR I 1 TO 7 DO ACT Samples I EXPO MeanArrT 1 ASSI MBac 1 7 98 106 86 113 102 122 104 DECL VAR MBac ARRAY 1 7 OF REAL I INTEGER MeanArrT ARRAY 1 7 OF REAL MESSAGES Samples BactConc REAL The messages samples to be analyzed in a Lab arrive at random from seven original points and after being assigned a value for BactConc by means of a GAMMA function they are delivered to one of the seven nodes LabSec according to their source 4 Hangar I Quarry INO Mine City SENDTO City COPYMESS 5 IF ICOPY lt 3 THEN SENDTO Quarry IC0PY ELSE SENDTO Mine The produced message Truck is sent to City Five copies are made The 1 2 and 3 are sent respectively to Quarry 1 Quarry 2 and Quarry 3 The other two 4 and 5 are sent to Mine 4 2 L Line type nodes This type of nodes are used to simulate queue disciplines and sorting lines of items Messages coming to the node EL are passed to its IL where they are set in the order indicated by the code This may be FIFO First In First Out LIFO Last In First Out or any other order programmed by the user 4 2 1 Code It may contain Pascal instructions functions and procedures GLIDER common instructions
83. K KKKKKD DDD DD gt gt gt gt gt gt DD TIME NODE WINDOW 1 EXAM LIST IL_WINDOW 1 SEEK EXIT TIME 7 734 EXT MESS 2 GEN ENTRY FROM IL_WINDOW 1 LL 1 TIME ADD MESS 2 GEN ENTRY TO EL_EXIT 1 LL O TIME EXA MESS 3 GEN ENTRY EXT MESS 3 GEN ENTRY FROM EL_WINDOW 1 LL 3 TIME ADD TO FEL EV 2 IEV 1 TIME 11 858 ADD MESS 3 GEN ENTRY TO IL_WINDOW 1 LL O TIME EXA MESS 4 GEN ENTRY NODE EXIT 1 EXT MESS 2 GEN ENTRY FROM EL_EXIT 1 LL 1 TIME DELETED MESS 2 GENERATED IN ENTRY AT 0 353 NODE WINDOW 1 EXA MESS 4 GEN ENTRY Future Event List at Time 7 784 NODE ENTRY T 7 917 IND 1 EVP 0 NODE WINDOW T 11 858 IND 1 EVP 0 EVENT 1 IEV LOR RRR KKK KKKKKD DDD DD gt gt gt gt gt gt DD TIME NODE ENTRY 1 ADD TO FEL EV 1 IEV 1 TIME 11 890 ADD MESS 6 GEN ENTRY TO EL_WINDOW 1 LL 2 TIME NODE WINDOW 1 EXA MESS 4 GEN ENTRY NODE WINDOW 1 EXA MESS 4 GEN ENTRY Future Event List at Time 7 917 NODE WINDOW T 11 858 IND 1 EVP 0 NODE ENTRY T 11 890 IND 1 EVP 0 EVENT 2 IEV LOR RRR KKK KKKKKD DDD DD gt gt gt gt gt gt DD TIME NODE WINDOW 1 EXAM LIST IL_WINDOW 1 SEEK EXIT TIME 11 858 EXT MESS 3 GEN ENTRY FROM IL_WINDOW 1 LL 1 TIME ADD MESS 3 GEN ENTRY TO EL_EXIT 1 LL O TIME EXA MESS 4 GEN ENTRY EXT MESS 4 GEN ENTRY FROM EL_WINDOW 1 LL 3 TIME ADD TO FEL EV 2 IEV 1 TIME 16 019 ADD MESS 4 GEN ENTRY TO IL_WINDOW 1 LL O TIME EXA MESS 5 GEN ENTRY NODE EXIT 1 EXT MESS 3 GEN ENTRY FROM EL_
84. L P A Length_a C ORDER P A The messages are ordered by the ascending values A of the variable P computed from the field Length_a and the parameters A and C 4 3 G Gate type nodes This type of node retains or allows message flow The nodes type G have an EL for the retained messages 4 3 G GATE TYPE NODES 37 4 3 1 Code It may contain Pascal instructions functions and procedures GLIDER common instructions and procedures GLIDER functions the GLIDER instructions ASSEMBLE COPYMESS CREATE DEASSEMBLE SYN CHRONIZE SENDTO STATE and the procedures STOPSCAN and BEGINSCAN If there is a STATE instruction only one is allowed it must be the first in the code Its associated instruction may contain Pascal instructions functions and procedures GLIDER common instructions and procedures and GLIDER functions It cannot have SENDTO instructions 4 3 2 Activation It is activated by an event or during the scanning of the network if the EL is not empty The instruction STATE used to change the state of the gate is only executed if the node is activated by an event which refers to the node 4 3 3 Function 1 When the node is activated by an event that refers to the node and there is an instruction STATE this is first executed After this execution or when the node is activated because the scanning of the network the other non STATE part of the code may be executed 2 If the EL is not empty it is scanned start
85. LLOWS INTERACTIVE CHANGE OF DATA 2 ASSI Temp 1 5 899 221 700 037 988 111 655 15 408 599 INTI Temp 1 5 8 2 Furnaces Temperatures When INTI is executed it appears in the screen Furnaces Temperatures 1 2 3 4 5 899 22 700 04 988 11 655 20 408 60 C to continue other to modify If the user press C or c it appears Modify number 67 The user must indicate the number 1 to 5 to be modified The system asks for the new value The system rewrites the array modified and asks for new modifications until C or c is pressed See examples 1 6 8 9 10 13 14 16 18 19 GLIDER examples book 3 The second form of this instruction allows the interactive modification of functions defined by the user as GFUNCTIONS The mouse must be installed to use this option See example 21 GLIDER examples book Example Poli 0 20 35 50 45 70 60 45 75 42 100 50 Spli1 0 20 45 80 100 30 Spli2 0 1 5 10 10 40 20 20 40 30 70 50 100 60 Spli3 0 10 20 40 30 70 40 50 70 30 80 50 100 60 Esca 0 20 35 40 45 60 60 45 90 42 100 50 FrecR 1 2 5 2 3 4 3 2 3 1 FrecA 2 6 5 5 2 3 7 1 1 9 2 7 DiscoN 2 6 5 5 2 3 7 1 1 9 2 7 DiscoA Aa 5 Bb 3 Cc 4 Dd 7 DiscoR 4 1 2 2 5 3 4 5 6 1 4 4 7 7 5 5 INTI FrecR Poli Esca Split Spli2 Spli3 FrecA DiscoN DiscoA DiscoR TYPE Letters
86. NST Constants are identifiers to which values are assigned at compiler time or at initial run time as implemented in the TurboPascal extension of Pascal Compiler time declared constants cannot be the target of any assignment operation at run time The declaration syntax for compiler time declared constants is lt identifier gt lt value gt where lt value gt may be a constant expression of any type The declared constant implicitly takes the same type Initial run time declared constants have their type explicitly declared and can be the target of assignment operation at run time The declaration syntax for initial run time declared constants is lt identifier gt lt type gt lt list of values gt Examples CONST Flow REAL 30 7 Quantity INTEGER 12 ch Y 3 Load ARRAY 1 5 OF REAL 3 8 4 5 4 2 Markov ARRAY 1 3 1 3 OF REAL 0 2 0 4 0 2 0 7 0 2 0 3 0 1 0 4 0 5 2 3 VAR 23 2 3 VAR Variables declared in the DECL section are global to the model program i e they may be used anywhere in the program Variables declared in a node are local to that node and can only be used in the node s code Their values are not retained after node processing Variables declared in the MESSAGES subsection of the DECL section are fields of each generated message and may have different values in different messages Field variables are variables introduced by the GLIDER system one for ea
87. RST NEW lt integer value gt ALLI lt logic expression gt EQUFIELD lt field gt lt associated instruction gt The ASSEMBLE instruction is used to join a set of messages that came to a node maybe at different times and to represent the set by only one message named representant The representant may be the first assembled or a new message Represented messages may be deleted or maintained in a list for further disassembling The associated instruction must contain a SENDTO instruction to dispose of the representant The instruction is suited to simulate loading and transportation of things using the representant as the transporter ASSEMBLE can be used in a node with an EL that has the ability to send messages nodes of G L D and general type with EL When this instruction is executed the EL is scanned from the beginning Each message comparing mes sage is compared with those compared messages that follow it The first comparing message is the first one in the EL The values of the fields of the comparing message are in the field variables Those of the compared message are put in the 0_ lt variables gt The comparison consists in the evaluation of the lt logic expression gt that may include field variables of the comparing messages 0_ lt variables gt of the compared message and any other type of variables and constants If the expression is TRUE both the comparing and compared messages are candidates to be assemb
88. SSON random value from a Poisson distribution 25 RAND random value from a Multivariate distribution 26 TRIA random value from a Triangular distribution 27 UNIF random value from a real Uniform distribution 28 UNIFI random value from an integer Uniform distribution 29 WEIBULL random value from a Weibull distribution 8 1 LL number of messages of a list Syntax LL lt list name gt Returns the value INTEGER of the length of the list EL or IL indicated in lt list name gt Example IF LL Clerk1 lt 2 LL Clerk2 THEN SENDTO Clerk1 ELSE SENDTO Clerk2 8 2 MAXL maximum number of messages of a list Syntax MAXL lt list name gt Returns the value INTEGER of the maximum value attained for the list EL or IL indicatedin lt list name gt Example WRITELN The maximum in the third queue was MAXL EL_Dec Gat2 8 3 MINL minimum number of messages of a list Syntax MINL lt list name gt Returns the value INTEGER of the minimum value attained for the list EL or IL indicated in lt list name gt Example MaxiFreeSpali ParkSpali MIN IL_Parkingli 8 4 MEDL mean length of a list Syntax MEDL lt list name gt Returns the value REAL of the mean of the length as a function of time for the list EL or IL indicated in lt list name gt Example IF MEDL EL_Mac 1 gt 1 5 MEDL EL_Mac 2 THEN T_Mac 1 1 5 M_Mac 1 8 5 DMEDL DEVIATION OF THE MEAN LENGTH OF A LIST
89. TARD produces a delayed function from a given function of time SORT sorts a list of messages ee STAT displays the statistics 0 2 ee STOPSCAN stops the scanning of a list of messages 0 004 TAB adds values to a frequency table o o TRACE starts the tracing o e TRANS transfers a Message o UNTRACE stops the tracing o a UPDATE updates messages fields or field variables FUNCTIONS 8 1 8 2 8 3 8 4 8 5 LL number of messages of a list 0 o o MAXL maximum number of messages of a list o MINL minimum number of messages of a list MEDL mean length of a list o o e e DMEDL deviation of the mean length of a list CONTENTS CONTENTS 8 6 MSTL mean waiting time in a list o o e 8 7 DMSTL deviation of mean waiting time in a list o o o 8 8 TFREE time that the list was free o o o a 8 9 ENTR number of entries ina list o o e eo 8 10 MAX maximum value of a pair of real expressions 0200000004 8 11 MAXI maximum value of a pair of integer expressions o o 2 e 8 12 MIN minimum value of a pair of real expressions e ee 8 13 MINI minimum value of a pair of integer expressions o o e e o 8 14 MODUL rest f
90. TER 9 RESERVED WORDS e NEW in an ASSEMBLE instruction it indicates that a new message will represent the group e NREP number of the replication when the Replications option is used its use will be discussed in a future version of the GLIDER manual O_MESS used in UPDATE to update the fields of the alternative message being processed OUTEF alternative file variable in REPORT instruction e O_VAR used in UPDATE to update the fields variables of the alternative message being processed RKF indicates Runge Kutta Fehlberg method of integration RK4 indicates fourth order Runge Kutta method of integration TRUE used in the instruction ASSEMBLE instead of a logical expression VAR used in UPDATE to update the field variables of the message being processed VAR used in the heading of a node to declare local variables 9 21 Types of Node The following letters that indicate the types of node are not reserved words see chapter 5 however they are included here eG eL E gt azg 9 22 Constants e MAXREAL 1 7E38 e MAXINTEGER 32767 e MAXLONGINT 2147483647 e MAXWORD 65536 e PI 3 14159627 Chapter 10 OPERATION The GLIDER system operates in the MS DOS operating system 10 1 GLIDER system The Operation of the GLIDER system needs at least the following files to function in its elementary form UG8 EXE GLIDER compiler TURBO TPL Turbo Pascal line compiler v 6 PP PAS GLIDER procedures FUNG TPU GLIDER
91. This reduces the mass of wood by a quantity that is 30 of the wm at most and MinCut at least Within these limits it depends on the difference between actual price and average price pm of the wood The variable w must be declared of CONT continuous type The time function price is given by the 7 pairs of values indicated in the INIT section For the time 0 its value is 30 for the time 10 it is 20 etc It is declared of real argument real value and the interpolation is made by a SPLINE algorithm A graph is programmed to display during the run w and the price as a function of TIME In the INIT section values to the parameters and to the initial value of the variable w are given The integration interval DT_Growth is also set All variables are declared in the DECL section In GLIDER programs the basic features are implemented in the following way e Each node is specified by a name a node type and normally a list of successors nodes to which it can send messages The type of the node must be defined The type implies specific ways of being activated and processing the messages e The code can include Instructions in Pascal language Turbo Pascal in the present implementation Structured GLIDER instructions Procedures and functions of the GLIDER library System generated instructions e Information exchange among nodes is accomplished by allowing the code of different nodes to share some of the data
92. URES PROCEDURE CountActBar VAR n INTEGER BEGIN ACT Bar 0 n n 1 WRITELN Bar activated n times END FUNCTION CubicRoot z REAL REAL BEGIN CubicRoot EXP LN z 3 END PROCEDURE FirstTrue VAR Count BoolArray i INTEGER VAR j INTEGER BEGIN j 1 WHILE j lt 4 AND NOT Count j do j j 1 IF j 5 THEN i 0 ELSE i j END Calls to these procedures may be CountActBar N CubicRoot 1728 0 FirstTrue CON k It was defined TYPE BoolArray ARRAY 1 4 OF BOOLEAN 2 10 STATISTICS The GLIDER system collects statistics of nodes and variables The nodes and variables for which statistics are desired must be specified by the user After the heading STATISTICS a list of node identifiers and simple real variable identifiers may follow The variables for which statistics are required must be initialized in INIT Tf one of the elements of the list is the reserved word ALLNODES the statistics of all nodes are given The statistics are always displayed at the end of the simulation run but they may also be called by the STAT procedure in the program or by user s interruption during the execution of the program Examples STATISTICS Dock Crane TotalWeight Statistics of the nodes Dock and Crane and the variable TotalWeight will be displayed STATISTICS ALLNODES TotalCash Money 1 Money 2 NumberTrans Statistics of all the nodes and the variables TotalCash Money
93. Y TO EL_WINDOW 1 LL TIME 000 NODE WINDOW 1 EXA MESS 1 GEN ENTRY EXT MESS 1 GEN ENTRY FROM EL_WINDOW 1 LL TIME 000 ADD TO FEL EV 2 IEV 1 TIME 4 409 ADD MESS 1 GEN ENTRY TO IL_WINDOW 1 LL TIME 000 Future Event List at Time 0 000 NODE ENTRY T 0 353 IND 1 EVP 0 NODE WINDOW T 4 409 IND 1 EVP 0 EVENT 1 IEV 1 OOO ORE ERED AAA AA TIME 353 NODE ENTRY 1 ADD TO FEL EV 1 IEV 1 TIME 0 888 ADD MESS 2 GEN ENTRY TO EL_WINDOW 1 LL TIME 353 NODE WINDOW 1 EXA MESS 2 GEN ENTRY NODE WINDOW 1 EXA MESS 2 GEN ENTRY Future Event List at Time 0 353 NODE ENTRY T 0 888 IND 1 EVP 0 NODE WINDOW T 4 409 IND 1 EVP 0 10 EVENT 1 NODE ENTRY 1 ADD TO FEL EV 1 IEV 1 TIME ADD MESS NODE WINDOW 1 EXA MESS NODE WINDOW 1 EXA MESS Future Event List at Time IEV 3 2 2 1 GEN GEN GEN NODE ENTRY NODE WINDOW EVENT 1 IEV 1 NODE ENTRY 1 ADD TO FEL EV 1 IEV 1 TIME ADD MESS NODE WINDOW 1 EXA MESS NODE WINDOW 1 EXA MESS Future Event List at Time 4 2 2 GEN GEN GEN NODE WINDOW NODE ENTRY EVENT 2 IEV 1 NODE WINDOW 1 EXAM LIST IL_WINDOW 1 EXT ADD EXA EXT ADD MESS MESS MESS MESS TO FEL EV ADD MESS EXA MESS NODE EXIT 1 EXT MESS DELETED MESS NODE WINDOW 1 EXA MESS Future Event List at Time 1 WONNNNEF 3 GEN GEN GEN GEN TEV GEN GEN GEN 1 GEN NODE ENTRY
94. ad de los Andes M rida Venezuela Tutor G Tonella Zambrano T 1992 Modelo Preliminar de Simulaci n del Crecimiento en Area Basal para Planta ciones de Teca Trabajo de Maestr a en Ciencias Forestales Preliminar Simulation Model of Basal Area Growth of Teak Plantations M S Thesis in Forestry Science Universidad de los Andes M rida Venezuela Tutor C Domingo
95. alled from the Menu the system asks if user want to keep the output shown in the screen in a file for detailed examination Tracing is terminated by pressing the T key several times or M to call the Run Interactive Menu See an example in the Chapter 1 10 7 Statistics The standard statistics of the simulation are requested by the STATISTICS declaration see 2 10 in which nodes and variables for which statistics are wanted are indicated Statistics are always displayed at the end of the simulation run They may also be displayed when a STAT instruction see 7 20 is executed or by request from the Run Interactive Menu The statistics presented are e The title of the experiment by default Basic Experiment The user can put other titles from the program see instruction TITLE section 6 27 or from the Execution Menu e The total time of simulation and the last time in which the statistics were initialized see procedure CLRSTAT section 7 4 e The number of the replication e The date and time of the beginning of the execution 116 e The CHAPTER 10 OPERATION real time spent in the simulation run e For the I type nodes the number of generated messages e For each EL and IL the statistics are e number of entries in the list e actual length e maximum length attained e mean length and its deviation e maximum waiting time that one message had to wait in the list e mean waiting for all the messages that were
96. alue is the remaining time of a preempted message although it must be declared by the user in a MESSAGES declaration it is managed by the instruction PREEMPTION 9 2 Event variables e IEV integer index of the event e EVP byte parameter of the event e SU boolean parameter to suspend the event 107 108 CHAPTER 9 RESERVED WORDS 9 3 Indexed node variable e INO integer index of the node being executed also index of the EL from which the messages are selected from a type D node with multiple predecessors 9 4 Control and state variables ICOPY integer number of the copy produced by a COPYMESS instruction EXTREL boolean TRUE if there was extraction of messages by an instruction REL SYNC boolean TRUE if there was assembling or synchronization of messages by ASSEMBLE or SYNCHRONIZE instructions SENT boolean TRUE if a SENDTO was executed RND lt integer gt real index from 1 to 10 is the actual value of the random number between 0 and 1 of the stream given by the index RN lt integer gt real index from 1 to 10 is the actual value of the random number between 1 and the module 21474836647 of the stream given by the index Its initial value is the seed of the stream This value can be changed by the user 9 5 Node dependent variables In the following lt node name gt includes the index between if the node is multiple e IL lt node name gt designs the internal list of the node EL lt node name
97. and procedures GLIDER functions the GLIDER procedures LIFO FIFO and ORDER and the GLIDER instructions SENDTO ASSEMBLE SYNCHRONIZE and CREATE 4 2 2 Activation It is activated by an event that refers to it or during the scanning of the network if the EL is not empty 4 2 3 Function 1 When the node is activated the EL is scanned and each message is extracted one by one For each extracted message the fields are transferred to the corresponding field variables and the code is executed If there are not LIFO ORDER or SENDTO instructions in the code the message is put at the end of the IL 2 If FIFO is executed the message is put at the end of the IL 36 CHAPTER 4 SYSTEM PREDEFINED NODES If LIFO is executed the message is put at the beginning of the IL If ORDER is executed the message is put in the IL according to the specification of this procedure See 7 15 that may sort the IL according to the values of a variable If SENDTO is executed the message is not added to the IL but sent to the list s indicated in the SENDTO Before the transfer the field variable values are passed to the messages fields Only one of the instruc tions LIFO FIFO ORDER or SENDTO must be executed if some of them are in the code The messages in the IL are not extracted automatically in the node To extract a message from the IL a user s instruction must be executed in this or other node or the action of automatic instructions
98. arameters iii DEAN NON OA oon nN NNN NY NY NY NNN NNW WD eon ATF Fw WN Nw Nw CO iv CONTENTS 3 5 Values from DBASE IV Tables to Arrays 2 0 0 ee 31 3 6 Initial Activations aaa 31 3 7 Interactive Experiments 31 SYSTEM PREDEFINED NODES 33 4 1 I Input type nodes e 33 41 1 Code noaa aaa 33 4 1 2 Activation oaa ee 33 A a 33 4 1 4 Relation with other nodes 2 2 2 e 34 4 1 5 ladera 34 4 1 6 Examples 0 34 4 2 L Line type nodes 2 2 aa 35 4 2 Code ee 35 4 2 2 Activation oaa 35 4 2 3 A a 35 4 2 4 Relation with other nodes Identifying of IL with EL 36 4 2 5 Indexes 2 ee 36 4 26 Examples 0 36 4 3 G Gate type nodes e 36 4 3 Code ee 37 4 3 2 Activation ooa aaa ee 37 4 3 3 Function aoaaa ee 37 4 3 4 Relation with other nodes 0 2 ee 37 4 3 5 Indexes 2 a 37 4 3 6 Examples 0 38 4 4 R Resource type nodes 2 a 38 4 41 Code noaa aaa a 38 4 4 2 Activation oaa 39 4 4 3 Function oaaae a 39 4 4 4 Relation with other nodes e 40 44 5 Indexes 0 40 44 6 Examples oaaae 40 4 5 D Decision type nodes 2 a 41 4 5 1 Code noaa aaa a 41 4 5 2 Activation oaa 41 4 5 3 Function aaa aaa 41 4 5 4 Relation with other nodes 2 2 ee 41 4 5 5 Indexes o oo aaa 41 4 5 6 Examples 0 ee 41 4 6 E Exit type nodes 20 0 e 42 46 1 Code ee 42 4 6 2 Activation 2 ee 42 46 3
99. aration is TABLES It must be followed by one or more declarations of the form lt variable identifier gt lt table identifier gt lt variable identifier gt is the name of a simple real variable whose values through time are to be tabulated lt table identifier gt is the identifier assigned to the table The tabulation of values must be commanded by the user with the TAB procedure see 7 22 2 8 DBTABLES The GLIDER system can import update and export files generated by a data base system DBASE IV in this implementation A data base file is a succession of records each with a set of fields All the records in a file have the same structure The records usually describe the characteristics of individuals of a set people objects years cities etc by means of the values of the fields These are simple tables DBASE file in order to be suitable for GLIDER processing must have as its first field in its record structure a primary key field named with the same file or table name Association tables are used when the values of a relation of two or more sets have to be described For each combination set of two or more individuals one of each set there is an entry in the table that describes by one or more fields the characteristics of the relation In the actual version only complete tables can be imported i e all the possible combinations of records in the associated tables must appear In an association table of N simple tabl
100. as Mean waiting at lock entrance 7 18 The procedure PAUSE stops the process to allow to read the output OUTG Pass_Number 1 6 5 Number of passengers at each bus stop If the content of the array Pass_Number is 2 4 12 7 5 16 then the following is written in the screen Number of passengers at each bus stop 1 2 3 4 5 6 2 4 12 7 5 16 See examples 1 6 18 GLIDER examples book 6 17 PREEMPTION ALLOWS A MESSAGE TO PREEMPT ANOTHER THAT IS USING THE RESOURCE71 6 17 PREEMPTION allows a message to preempt another that is using the resource Syntax PREEMPTION lt logical expression gt REMA lt associated instruction gt This instruction is used to remove a message that is occupying a resource represented by a R type node of size 1 with a STAY instruction It may be used only in a R type node of capacity 1 but not in the RELEASE instruction It is executed when some message is in the EL and it is examined When executed the IL is checked If it is void the message enters the IL and nothing more is done If it is not free then the fields of the message in the IL are passed to the corresponding 0_ lt fields gt and the lt logical expression gt is evaluated it is FALSE the examined message remains in the EL and nothing more is done If it is TRUE then the ccupying message is removed from the IL and the new message occupies the resource enters the IL When is preemption process happens the lt associated instruction gt
101. ay includes changes in the fields conditional sending to different nodes and a NOTFREE instruction to inhibit the freeing of the used resource It may also contain common GLIDER instructions and procedures but their associated instructions must not contain GLIDER instructions with associated instructions The instruction when it is used must be the first in the code of the node It is executed only ifthe node is activated by an event The execution is not repeated during the scanning of the network When the instruction is executed a scanning of the IL starts looking for a message with the exit time of the IL that is recorded in the field XT If such a message is not found an error condition occurs If it is found its fields are passed to the corresponding field variables and the lt associated instruction gt is executed This instruction must execute a SENDTO instruction to dispose of the message In the process unless NOTFREE is used a quantity of resource is freed that is equal to the value of the USE parameter of the message So the variable F_ lt node gt is increased by USE and U_ lt node gt is decreased by USE If the capacity of the resource is the constant MAXREAL the resource is considered of infinite capacity and no change in those variables is made If the ALL parameter is used the search for other messages with the same XT continues until all of them are processed This instruction can be used in R type nodes E
102. bled messages depends on the first parameter e assembled group and the remaining of the group FIRST indicates that the represen assembled list pointed by the representant instruction If the representant has yet an assemb is list assembled messages are added to t ant is the first of the assembled group and the rest are put in an This allows the retrieval of them by a DEASSEMBLE ed list from a revious assemble process the new NEW indicates that a new me of its fields are co instruction gt The lt associated instruction gt executed for each successful assemb ant assigning values to field variables and must have a SENDTO instruction to the fields of the represen dispose of the representant Note tha in the lt logical condition gt and in group or for a new execution of the there was some successful assemble See the instruction SYNCHRONIZE Examples 1 Unite_Parts ASSEMBL BEGIN S Groups of three messages with ied from the first of the grou This new message points to the assembled lis through a DEASSEMBLE instruction representant of the assembled group The values but they can be changed in the lt associated so that it may be later retrieved ssage is created as e may have instructions to change instruction may change the values of variables he lt integer value gt so changing the assemble conditions for the next ASSEMBLE instruction Assembled messages cannot be changed If e
103. ch field name in messages having the name of the field They are global and change their values each time a message is processed taking the values of the corresponding fields of the processed messages Note that if messages of different structure have fields of the same name they must be of the same type and GLIDER introduces for them only one field variable Example MESSAGES Cans Diameter Height Weight REAL Packages Length Wide Height Weight REAL The fields Height and Weight are in both record messages Field variables having these names are system created so different messages may share same processes on these characteristics The declaration of variables reserves memory for them After the VAR specification one or more declarations of the following type follow lt list of variable names gt lt type gt The lt list of variable names gt consists of one identifier or many identifiers separated by commas lt type gt may be a predefined type identifier a user defined type identifier or a type specification written with the same syntax given for type declarations Examples DECL TYPE VecType Small Large Truck Color Rer_L Yellow_L Green_L VecChar RECORD Size Weight REAL VType VecType END VAR VMax Length Slope REAL Ntotal j k INTEGER Semaf Color Vehicle ARRAY 1 30 of VecChar Connections ARRAY 1 5 1 8 of BOOLEAN X Y CONT InpFreq ARRAY 1 4 1 3 OF FREQ
104. d only in the RELEASE instruction of R type nodes Example Lock R Ocean RELEASE BEGIN NOTFREE SENDTO Ocean Fill END STAY T_Enter T_Ebbing T_Leaving Fi R Elim RELEASE BEGIN FREE Lock SENDTO DestrMess END STAY T_Filling Messages vessels queue up at a lock to go down to the ocean level The time spent in the dock is for the entrance maneuvers lowering the level of the water and going out The dock is again freed for use after the dock attains again the upper level This is simulating by not freeing the lock when the message goes out and by sending a copy to the node Fill This delays the message by the filling time and then the resource is freed See FREE procedure section 7 10 7 15 ORDER PUTS THE MESSAGE IN THE IL OF A L NODE IN A GIVEN ORDER 91 7 15 ORDER puts the message in the IL of a L node in a given order Syntax ORDER lt real variable gt A DI It is used to put the IL of a L type node in a certain order Messages arriving to the EL are passed to the IL and put e If the second argument is A before the first in the IL that has greater the value of lt real variable gt e If the second argument is D before the first with lower value of lt real variable gt e If none is found the message is put at the end of the IL With the argument A an ascending order is obtained with the D a descending order It may be used only in L type nodes Examples OrdLine L if Prior
105. de grado GLIDER Model of Sugar Mill at Rio Turbio Thesis Escuela de Ingenier a de Sistemas Universidad de los Andes M rida Venezuela Tutor C Domingo 4 Domingo C 1988 GLIDER A Network Oriented Simulation Language for Continuous and Discrete Event Simulation Intl Conf on Math Models Madras India Aug 11 14 5 Domingo C y Hern ndez M 1985 Ideas B sicas del Lenguaje GLIDER Basic Ideas of GLIDER Language Mimeografiado IEAC Universidad de los Andes Octubre de 1985 M rida Venezuela pp 37 6 Domingo C y Hern ndez M 1988 GLIDER A Network Oriented Simulation Language 2nd Work shop on Computer Performance Evaluation Milan May 30 Jun 1 7 Domingo C M Hern ndez M Sananes J Silva y G Tonella 1989 GLIDER A New Simulation Language Intl Congress of New Technology for the Development of Software and Supercomputers Caracas Venezuela Nov 29 Dic 1 8 Domingo C G Tonella H Hoeger M Hern ndez M Sananes y J Silva 1993 Use of Object Oriented Programming Ideas in a New Simulation Language in Schoen ed Proceedings of Summer Computer Simulation Conference Boston 19 22 de Julio de 1993 pp 137 142 9 Domingo C Quiroz S Ter n O 1994 Sistema Estad stico para el Lenguaje de Simulaci n GLIDER Statistical System for Simulation Language GLIDER Meeting of Venezuelan Society of Biometric and Statistics Caracas Julio 1994 10 Do
106. e Identif Age Year Score 6 6 DEASSEMBLE DISASSEMBLES ASSEMBLED MESSAGES 61 FOR J 1 TO N_Student1 DO Student1 Age J Student1 Age J 1 DECL DBTABLES MainFiles Student1 NewFiles Student2 The fields Age Year Score of the DBASE table Student1 are charged in the running program through the LOAD instruction into the arrays Student1 Name Student1 Identif etc They may be changed by the program An example of the change of age is shown After the changes are made the values are written by means of the DBUPDATE instruction into the corresponding fields of the table Student2 The other fields of the table Student2 remain unchanged The variables N_Student1 Student1 Age and similar variables for the other fields are introduced automatically by the system with the information taken from the declared DBASE IV tables They may be managed by the programmer as arrays with index corresponding to the record number Note that the two files may be in different directories See example in section 2 8 6 6 DEASSEMBLE disassembles assembled messages Syntax DEASSEMBLE lt associated instruction gt This instruction is used to extract messages from an assemble list generated by an ASSEMBLE instruction When it is processed it is supposed that a message is being processed Then it is checked ifthe message has a pointer to an assemble list If there is not that list nothing is done If there is a pointer to a list the list is scanned from
107. e The messages are sent In the Control node that represen maximum capacities are assigned in 0 if it is engaged When the Contro he code for each message Only ifi capacity in the The channel is Control only al The exit from the channel is schedu message abandons the resource it hat takes care disposed according to its type If If it has type 4 that is the type t Departure node The node Pier is a multiple node he corresponding type of ship T When the capacity is di This is done by the instruc unit of the resource This The operation time in the value used is different T he received ship is put ship of type 4 is sent to De it is would arture The departure node is of E The code is the computa message that time that the Pier of its type and the C he message from the EL and sends it to is not of the outgoing message Remarks about the program s the control of entry F_Pier ShiTyp holds at each moment the value of the he INIT section 4 F_Channel has the same meaning for the resource C node that is a ty find a message for w annel is free the EL of the node Channel represented by the resource type node Channel network this node takes the message in its EL and passes it to the IL this will be empty ows to pass a message if ed for F_Channel CHAPTER 1 INTRODUCTION The messages have a field a declaration is issued in the subsection e generating node iTyp
108. e FEL efore the end of service event scheduled for TIME 4 409 The generated messages are added to EL_Window and remain there because the IL is occupied The next event is of type 2 activation of Window at TIME 4 409 scheduled at TIME 0 This event examines he IL of Window seeking for a message with EXIT TIME 4 409 The message is extracted and added to he EL of the Exit node Then the EL of Window is examined The next message number 2 in the queue EL_Window is extracted its exit time is scheduled at time 7 784 and the message is added to the IL of Window The following message umber 3 is also examined but as the IL is occupied the message remains in the EL n n E the same event the node Exit is activated the message number 2 extracted from its EL and deleted e network excluded the Entry node that is of I type is scanned again and as no messages are moved e next event in the FEL is processed ost in the FEL next arrival and next end o e examination of traces is very useful to un T h The reader can continue the examination of t m T is simulation In this simple example only two events are at service In more complex models the FEL can be longer erstand the GLIDER system works It is also very important or debugging Future Event List at Time 0 000 NODE ENTRY T 0 000 IND 1 EVP 0 EVENT 1 IEV 1 OOO ORE ERED AAA AA TIME 000 NODE ENTRY 1 ADD TO FEL EV 1 IEV 1 TIME 0 353 ADD MESS 1 GEN ENTR
109. e does not include Turbo Pascal V 6 Some unit of this system are required to use the GLIDER This system must be obtained from Borland International or authorized dealers 11 3 Differences of Version 4 0 July 1996 with the previous versions 11 3 1 Introduction Only the main differences are listed below The first prototypes developed during 1985 1987 had very few commands such as STAY STOP TSIM TIME FIFO LIFO STAT USE PREE for Preemption ACT ORDER ASSEMBLE SYNC They included the 6 basic nodes G L I D E R and the following commands for the lists EXAM EXTRACT MOVE ACREF FIN SORT None of these were included in the later versions In addition the code of nodes were divided depending of the code functions for example in the following parts Assign Next File Revi Use etc The heading of node was completly different from the present version 11 3 2 Version alfa 1988 and beta 1989 The alfa and beta versions are more similar to the present version The alfa version was including the instructions POINT EXAM EXTR MOVE to use records It includes other commands that disappears in the version 1 such as NOSUG EXAM MOVE The beta version included in addition to the alfa version the instructions EXTR GRAPH SCAN CLRSTAT DEASSEMBLE TRACE UNTRACE DONODE DOEVENT RELEASE STATE TAB and most of the basic GLIDER functions It included also node with subindex multiple node 11 3 3 Version 1 February 1991
110. e explained above will happen ase only one message may be in the IL The message is then extracted and sent to the EL of r node Exit As this message movement triggers a new scanning of the network the node Wind r message to be passed to the IL If it is so a storage se the Window remains idle compiler assumes that the type is indicated uence of the scanning of the network started e node Exit removes the message of its EL rst letter ofits name When it is activated as a conseq xtraction event in the node Window the procedure of t and destroys it restoring the freed memory to a free memory pool During all these operations statistics are recorded of the lists and the use of the resources 1 4 2 Trace of the operations The user can ask from the Run Interactive Menu for an execution of the events one by one and a display of some of the effects of the executions This is useful for a detailed understanding of the process and for debugging purposes A partia must be e Be eT eA 1 oT o eT In the example rder of t firs trace of the simulation of this program is shown below To follow the trace the following remarks regarded ore each event the status of the Future Event List is displayed e next event is taken from the first element of this list the beginning notice that the only event is the arrival introduced in the INIT section The index is he node
111. e gt INTI lt list of GFUNCTIONS gt This instruction allows the interactive modification of initialized data lt variable gt is the name of a simple or indexed with only one index arithmetical variable If the variable has an index the name must be followed by lt lowest value gt lt highest value gt that indicates the range of the array to be changed lt format gt consists of two integers lt number of places lt number of decimals gt This define the format of the values presented to the user lt title gt is a string of characters without or apostrophes that contains a description of the variable This instruction may be used in the INIT and NETWORK but never within GLIDER instruc tions or I O instructions Examples INTI Alfa 9 2 Scattering angle When this instruction is executed Alfa must have an assigned value Let it be 1 058 As it appears in the INIT section see chapter 3 it will appear before the simulation in the screen Scattering angle 1 06 C to continue other to modify If C or c is pressed nothing is done and the execution continues If another key is pressed it appears Scattering angle The user must write the new value and press enter For example if 1 2 is written then the following appears Scattering angle 1 20 C to continue other to modify The user may change this value again When C orc is pressed the variable Alfa takes the last assigned value 6 12 INTI A
112. e message the actual values of the field variables are passed to the message fields 4 1 4 The no 4 1 5 Relation with other nodes e must have successors that can accept messages in their EL but it must not have predecessors Indexes In a multiple node the activations of the nodes occur independently In this case a successor must be explicitly indicated If the successor has index too then a SENDTO instruction may indicate the destination node 4 1 6 1 Examples I This node can only be activated from the INIT section or from another node It generates a message and sends it to the successor node by default the following in the program MainEntrance I Office1 Office2 F Number lt 40 THEN IT TRIA TBAMin TBAMode TBAMax ClassOff FunClass F ClassOff Normal THEN SENDTO Office1 ELSE SENDTO 0ffice2 INIT TIME 5 TSIM 2000 ACT MainEntrance 0 BAMin 3 TBAMode 5 TBAMax 8 FunClass Normal 4 Special 1 DECL TYPE Tc Normal Special VAR TBAMin TBAMode TBAMax REAL MESSAGES MainEntrance ClassOff Tc h REAL GFUNCTIONS FunClass FREQ Tc REAL 2 4 2 L LINE TYPE NODES 35 Messages are generated and sent to Officel or Office2 according to the field Class0ff whose value is given by the function FunClass Up to 40 messages are generated The time between successive generations are taken from a triangular distribution 3 Samples I 1 7 LabSec
113. e network when the EL is not empty 4 4 1 3 Function If there is no RELEASE instruction the departing of a message from the IL is automatically made as follows when the depart event pointing to the node is executed the message with the time of depart XT equals to the actual value of TIME i e the time of the departing event is extracted from the IL and sent to the successor nodes If there are more than one successor node copies are sent to all of them The value of the freed and used resource account is updated see 3 below The part of the code used by the system to process the departing message is only executed one time in the event and is not repeated during the scanning of the network The user can control the departing process of the message by means of a RELEASE instruction This is only executed if the R type node is activated by an event that refers to the node The associated instruction is executed only one time at the beginning of the event and not repeated during the scanning of the network The execution begins as in the automatic case by seeking the first message with an exit time XT equal to the actual TIME If it is not found a message error of empty list is given If it is found the message is extracted the fields are copied in the field variables and the user s code in the associated instruction is executed This code must have a SENDTO instruction to send the message to one or various successor
114. e or from the INIT section 4 9 GENERAL TYPE NODES 47 2 GraphProPri A IT 0 125 GRAPH O 50 BLACK TIME 6 1 WHITE Prod 7 1 Production 0 1000 RED Price 7 1 PriceInd 0 2 Yellow Each interval time of 0 125 units 8 times per year points with the new values of Prod and Price are added to the time graphic and united by a line to the previous point The node must be activated for the first time from other nodes or from the INIT section 3 NewStr A NewSource IT 0 5 If CondStCh THEN BEGIN ACT NewSource 0 CREATE MessSource SENDTO NewSource DEACT Inst3 A S C CT Proc4 12 AT LRSTAT END Each 0 5 units of time the boolean function CondStCh that may compute conditions for a structural change is evaluated If it is TRUE the nodes NewSource and with a delay Proc4 are activated The Inst3 is deactivated A message is sent to the newly activated node The statistics are displayed and then initialized for a new statistical gathering 4 9 General type nodes Used to general processes programmed by the user A node of this type may be designed by any other letter different of G L I D E R C A The node is activated during scanning processes this is the main difference with the A type It has not EL or IL unless this is explicitly required by the user in a NODES declaration The management of these lists must be programmed by the user with the help of GLIDER instructions a
115. e the input but retarded in time by the quantity lt delay gt The output variable must be declared in a declaration in the form lt variable name gt RET lt order gt An order n delay is calculated for a set of n differential equations This procedure may be only used in a type C node Example Spp C Demand K Demand GovDemand TIME RETARD 4 Supply Ret_Months Percep Demand The values of Demand are produced by the differential equation The Supply tends to adjust to the Demand affected by a perception factor of the Demand This factor may depend on other socioeconomic variables 7 19 SORT sorts a list of messages Syntax SORT lt list name gt lt field gt l A DI It is used to order an EL or IL by the ascending A or descending D values of o field of the messages This procedure can be used in nodes of any type Example 7 20 STAT DISPLAYS THE STATISTICS 93 OrdBatch G IF LL EL_OrdBatch gt 10 and F_Process gt 0 THEN BEGIN SORT EL_OrdBatch ProcTime A SCAN EL_OrdBatch SENDTO Process END Process R STAY ProcTime INIT TSIM 200 ACT Arrival 0 Process 10 DECL MESSAGES Arrival ProcTime REAL Messages parts that need different times to be processed at Process field ProcTime must be ordered in increasing order of the process time to optimize the processing This have to be done by batches of 10 parts The node OrdBatch produces this ordering When the ar
116. eal expression gt to the field USE of the actually processed message When the message is processed by a R type node the message will try to use that quantity of resource The value of the USE field can be changed any number of times during a simulation run This instruction can be used in nodes of any type Example Warehouse R IF BoxSize Large THEN USE 4 ELSE USE 1 5 Chapter 7 PROCEDURES GLIDER procedures are 1 20 21 22 23 ACT schedules future activation of a node DEACT deactivates a node FIFO puts the LIFO puts the NOTFREE in ORDER puts PAUSE stops PUTFEL adds RETARD pro SORT sorts a STAT displays STOPSCAN s BEGINSCAN repeats the scanning of an EL BLOCK blocks future release events of node CLRSTAT initializes the gathering of statistics DEBLOCK suppresses blocking of future release events of node ENDSIMUL ends the simulation at the end of the actual event EXTFEL extracts an event from the FEL message at the end of the IL of a L type node FREE frees a resource message at the beginning of the IL of a L type node MENU calls the Run Interactive Menu METHOD defines the method of integration in a C type node ibits the release of a resource he message in the IL of a L type node in a given order he execution an event to the FEL uces a delayed function from a given function of time ist of messages
117. ed to the field variables So o them by its simple name When o the fields of the message he user s code can use and change these values referring he process of the message is over the values of the field variables are fields with the same name they correspond to the same h different entities sharing common properties is called the activation of the node At a point during the simulation ain nodes for the future The schedule is kept in a list element in the FEL represents a pending event It contains a reference ime at which the activation must take place This list is automatically rocessed by th The order of ac rocessing of th The code of the rocessing In allow other no To perform all is activated executed an e system but the user may also han ivation of the nodes is essential to e element of the FEL that has the minimum time value The node re this starts the event execution articular this execution may cause message exchanges It can also c es to move messages or change values of variables All this must be of the node T ese scanned nodes are then activated The scanning is repeated cycl movements of messages are possible The event processing is then ended and the fol FEL will be considered During the execution of an event the state of the system changes and new future events are sche in the event W the FEL So the en a new event is executed the time variable is u
118. el Pier R 1 3 Channel STAY GAMMA TPier ShiTyp 0 1 TPier ShiTyp USE 1 ShiTyp 4 Departure E TinSys TIME GT TAB TinSys TabTSys INIT SIM 1200 ACT Entrance 0 barr 4 Mean time between arrivals Channel 0 2 Time to pass the channel FTyp 1 50 2 40 3 10 Values of frequency of types ASSI Pier 1 3 4 2 1 Capacities of the piers ASSI TPier 1 3 20 12 28 Mean time spent in the piers abTSys 0 15 5 Parameters of the frequency tablex ITLE Port Basic experiment NTI TPier 7 2 Time in the Pier DECL VAR Tbarr TinSys TChannel REAL TPier ARRAY 1 3 OF REAL MESSAGES Entrance ShiTyp INTEGER structure of the messages TABLES TinSys TabTSys table of frequencies for TinSys GFUNCTIONS FTyp FREQ INTEGER REAL 3 frequency function STATISTICS ALLNODES 14 END 1 5 1 The ships are represented by messages generated by the I type node Entrance e messages must have this h reference to t 2 or 3 to the S in the GFUNCTIONS declaration The values of the frequencies are given in the INIT value 1 frequency 50 value 2 frequency 40 value 3 frequency 10 The function FTyp according to those fre o the EL of the no field ShiTyp To declare that t MESSAGES of the DECL section wi The Entrance node assign value 1 is given by the function FTyp define roduces a random number 1 2 or 3 messag
119. emp UNIF 1 2 1 3 IF O_Temp gt 15 5 THEN SENDTO Process END When Heating is activated each 10 units of time the EL of a node Line is scanned A quantity random value between 1 2 and 1 3 is added to the value of the field Temp of the message If one message surpasses the value 15 3 it is extracted and sent to Process 2 Depot R TakeHighest A Group 6 22 SELECT SELECTS MESSAGES FROM ELS OF A D TYPE NODE 75 H 0 PHigh NIL SCAN IL_Depot Pt IF O_Height gt H THEN BEGIN PHigh Pt H O_Height END SCAN EL_Group Pg IF O_X 3 THEN STOPSCAN IF PHigh lt gt NIL THEN EXTR IL_Depot PHigh SENDTO Pg A Group When TakeHighest is activated the message of the IL of Depot with highest value in the field Height is found and sent to the EL of Group and put after the first message with field X equal to 3 6 22 SELECT selects messages from ELs of a D type node Syntax SELECT lt list of nodes gt lt multiple node gt lt range gt lt integer value gt lt associated instruction gt It is used to select messages from ELs of a type D node corresponding to its predecessors lt list of nodes gt is a list of predecessor nodes of the D type node lt multiple node gt lt range gt is the name of an antecessor multiple node with a range within the range of the node indexes lt integer value gt is an integer positive constant or an integer type variable with positive values When the instruc
120. en at TIME 0 in this example The other instructions of the INIT section assign values to the parameters e simulated system entrance the NETWORK The patrons The node Entry is of I type Its successor node to which messages can be sent is the node Window In em takes the following node as ich the compiler translates it e successor node This is done i e the next activation of the node Entry may also be scheduled This is done by assigning a value to t e system variable IT Interval Time This value is interpreted as the time that has to pass until the next arrival In this case this interval is the value computed by the function EXPO that generates a pseudorandom value taken from an exponential distribu This activation wi The user can also Values to the field The no by default no o ion see Chap loccur at a time that i con s of e Window simu er 8 for further ex rol the sending of he message can also be assigned in the code of this node ates a resource in her capacity was assign CHAPTER 1 INTRODUCTION anations So the GLIDER schedules a new activation of Entry equal to the actual value of TIME plus the value assigned to IT he message to other nodes by means of a SENDTO instruction S is case the window where the patrons are served The capacity is ed so that only one message can enter the IL The messages enter eing se his wi he firs using t means a future o
121. eq DISC INTEGER INTEGER 5 STATISTICS ALLNODES END 6 23 SENDTO sends messages in process to lists Syntax SENDTO lt lt pointer gt A B gt FIRST LAST gt lt destination list s gt This instruction is used to send messages to one or more lists of messages lt destination list gt is a list of names of nodes or lists they may be of the form EL_ lt node gt or IL_ lt node gt Message in process is sent to all these destinations if the list has more than one element copies are sent at each destination If one destination is indicated by a node it is assumed that it must be sent to the EL of the node The place in the destination list in which the message is put depends on the first parameter e LAST the message will be appended at the end of the list FIRST the message will be put at the beginning of the list e lt pointer gt B the message is put before the pointed message e lt pointer gt A the message is put after the pointed message e If the first parameter is omitted LAST is assumed 6 23 SENDTO SENDS MESSAGES IN PROCESS TO LISTS 77 When SENDTO is executed the values in the field variables are passed to the fields of the message and this is put in the indicated place If this instruction is within an lt associated instruction gt of a GLIDER instruction then the values in the 0_ lt fields gt are passed to the message except for the CREATE in which the field variables are used In
122. es is 2 then 2 messages are selected from each queue and sent to Assemb 2 Parts of five different types are produced at Pr with different processing times They are sent to a Selection subsystem When the production of each kind accumulates the required quantities given by the function FQuantReq for some types more than that may be produced the required quantities are selected and sent to Assembly This simulation is a part of a bigger model Its purpose is to see 76 CHAPTER 6 INSTRUCTIONS how many assembles can be made and how many unmatched parts remain NETWORK Pr I 1 5 Selection IT UNIF Tmin INO Tmax INO PartType INO SENDTO Selection Selection D Evaluate extraction condition Extract TRUE FOR INO 1 TO 5 DO IF LL EL_Selection PRLINO lt FQuantReq INO THEN Extract FALSE MAXSEL FQuantReq 1 IF Extract THEN SELECT PR 1 5 MAXSEL BEGIN MAXSEL FQuantReq INO SENDTO Assembly WRITELN MAXSEL Selected Type INO or PartType END Assembly E WRITELN TIME 8 3 0ut From PartType PartType PAUSE INIT TSIM 50 FOR INO 1 TO 5 DO ACT PRLINO UNIF Tmin INO Tmax IN0 TITLE Test Select 1 ASSI Tmin 1 5 2 8 3 5 3 6 3 9 1 5 ASSI Tmax 1 5 4 8 7 2 7 6 8 4 3 5 FQuantReq 1 2 2 1 3 1 4 1 5 2 DECL VAR Extract BOOLEAN Tmin Tmax ARRAY 1 5 OF REAL MESSAGES Pr PartType INTEGER GFUNCTIONS FQuantR
123. es of people that are to be served one by one in a window They enter the system at random and the serving times are also random left the system The GLIDER program may be as follows Simulation of a simple serving system Patrons enter the system to be served at a window The times between arrivals are taken at random from an exponential distribution with mean Tba The patrons are served or form a queue in front of the window The serving time is taken from a gaussian distribution with mean MeanWait and standard deviation StaDev Once they are served they go to Exit to leave the system The simulation is to go until time 1000 Statistics of nodes are After being served they required For clarity reserved words are written in uppercase letters NETWORK Entry 1 Window IT EXPO Tba Window R Exit STAY GAUSS MeanWait StaDev Exit INIT TSIM 1000 ACT Entry 0 Tba 4 MeanWait 3 8 StaDev 0 8 DECL VAR Tba MeanWait StaDev REAL STATISTICS Entry Window Exit END The program has four sections divided by three separators NETWORK INIT and DECL e The initial section is a text explanation may be include hat no line of the text can s section that can be extended to a full documentation art with the word NETWORK because this is t NETWORK section must start with t etween parenthesis or may This section contains the nodes of the he line except blanks and comments etter between
124. es the names of these tables must appear as the first N fields in each record conforming the primary key of the association The user must give in a DBTABLES declaration the names of the tables and the association indicator i e how many simple tables are associated in the declared table The declarations have DBTABLES as a heading followed by one or more declarations 26 CHAPTER 2 DECLARATIONS lt table name gt lt association indicator gt These declarations must be separated by commas and each or some groups of them may be delimited by The groups are also separated by commas ing DBASE file optionally preceded with di Lis assumed lt table name gt is a name of an exis rectory path lt association indicator gt is a number from 1 to 5 If omitte simple table The declarations that are in a group within are assumed to have the same structure Example DBTABLES GroupP1 GroupP2 Goods ConsPatt 2 CPati 2 Declares two sim structure and two le tables GroupP1 GroupP2 of the same s ructure a simple table Goods of different tables that are association of two tables and have the same structure The two first fields of ConsPatt must have as name the name of the two simple tables that ConsPatt associates Such simple ables must have been declared before All the declared tables must exist as DBASE tables The compiler uses information from these tables If hey are in other
125. essages arriving at E are destroyed 2 Exit E Tis GT TIME Tab Tis TablST INIT Tab1ST 0 0 12 5 0 DECL TABLES Tis TablST The time that the messages remained in the system is computed by subtracting from the actual TIME the generation time GT This value is recorded in a frequency table 4 7 C Continuous type of nodes This nodes solve systems of ordinary differential equations of first order This nodes do not have EL or IL 4 7 C CONTINUOUS TYPE OF NODES 43 4 7 1 Code It may contain Pascal instructions functions and procedures GLIDER common instructions and procedures GLIDER functions the GLIDER instruction CREATE and the procedures RETARD and METHOD see 7 18 and 7 13 It accepts successions of instructions of the form lt variable gt lt expression gt These may be mixed with other type of instructions The system considers a series of such instructions of the above type without other type of instructions among them as a system of differential equations So various differential systems can be represented in a unique node separated by ordinary instructions The systems of the same node share a common METHOD and path of integration In different C type nodes the METHOD and path of integration may be different In the above instruction lt variable gt is a variable that was declared of CONT continuous type It may have a numerical index If the variable TIME appears in some equation it must be
126. essing time It takes the value at each event At the beginning is 0 when the first train arrives is 25 when the second train departs is 45 when the second train arrives it is 70 when the third train departs it is 90 etc 1 1 2 Example of continuous simulation Plantation with periodic cuts In a plantation the quantity of wood growths according to a logistic curve whose differential equation is W kx 1 4 wm w When the quantity is greater than wm a cutting process starts which decides the proportion of wood to be extracted according to a function of the actual price p TIME and the mean price pm The time for the cut process is negligible compared with the rates of growth ETWORK 1 1 CHARACTERISTICS OF THE GLIDER SIMULATION LANGUAGE 3 Growth C w k 1 w wmax w if w gt wm then ACT Cut 0 GRAPH O 50 BLACK TIME 7 O WHITE W 6 O Wood O 10000 GREEN price TIME 6 0 Price 0 100 YELLOW Cut A w w MIN O 3 wm MinCut MAX O cc price TIME pm INIT TSIM 50 ACT Growth 0 k 0 21 wm 6000 MinCut 500 cc 40 2 pm 24 w 100 wmax 9500 DT_Growth 0 125 price 0 30 10 20 20 15 30 25 40 30 50 42 55 45 DECL VAR k wm wmax MinCut cc pm real w CONT GFUNCTIONS price SPLINE real real 8 END The type C node Growth solves the differential equation When w gt wm the node Cut of A type is activated
127. f entries in a list Syntax ENTR lt list name gt Returns the value INTEGER of the number of entries in the list EL or IL indicated in lt list name gt Example IF ENTR EL_Theater gt 120 THEN BLOCK Th_Arrival 8 10 MAX maximum value of a pair of real expressions Syntax MAX lt real expression gt lt real expression Returns the value of that lt real expression gt that is greater Example n 6 m MAX 7 MAX 8 n 2 The value assigned to m is 8 8 11 MAXI maximum value of a pair of integer expressions Syntax MAXI lt integer expression lt integer expression Returns the value of that lt integer expression gt that is greater 8 12 MIN minimum value of a pair of real expressions Syntax MIN lt real expression gt lt real expression Returns the value of that lt real expression gt that is lower 8 13 MINI minimum value of a pair of integer expressions Syntax MINI lt integer expression lt integer expression Returns the value of that lt integer expression gt that is lower Example Me MAXI MINI X1 X2 MAXICMINI X2 X3 MINI X1 X3 WRITELN Medium is Me 8 14 MODUL REST FROM DIVIDING TWO REAL EXPRESSIONS 101 8 14 MODUL rest from dividing two real expressions Syntax MODUL lt real expression gt lt real expression gt Returns the remainder that results from dividing the value of the first lt real expression gt by the second
128. f types I A and C are skipped in the scanning If the EL is non empty the code is executed When the last node in the program is scanned the scanning continues with the first one until the node activated at the beginning of the event is reached If during this process a movement of messages occurred then the scanning is repeated again When in a cycle no message is moved the event finishes and the next event in the FEL will be processed This scanning makes possible to take into account the consequences that the original event produced in other nodes Even if the original node do not move messages the scan is necessary because it can modify restrictions that maintain certain nodes inactive Although in most practical cases the programmer may be unaware of this process in complicated situations may be important to consider the activation process Some processes that would be simultaneous may fail to do so in certain cases Example If in a point of time three variables must change simultaneously for instance X gt Z gt U and the changes are in different nodes Aji Z X 6 B Ci X X 14 D U Z 3 E then if the event starts in node C and no message is moved in the event the scanning will not produce the change of U due to the change of X This may be solved by changing the order of the nodes or by a procedure ACT A 0 in the node D The user must decide from the nature of the problem what chain of modification makes sense and
129. ger expression lt stream gt Returns a REAL value of a random variable whose probability function is a binomial function with first pa rameter equal to the first lt integer expression gt and second parameter equal to the second lt integer expression computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 102 CHAPTER 8 FUNCTIONS 8 18 ERLG random value from an Erlang distribution Syntax ERLG lt real expression gt lt integer expression gt lt stream gt Returns a REAL value of a random variable whose probability function is an Erlang function This is the sum of a number equal to lt integer expression gt of exponential functions with mean equal to lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 19 EXPO random value from an Exponential distribution Syntax EXPO lt real expression lt stream gt Returns a REAL value of a random variable whose probability function is an exponential function with mean equal to lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 20 GAMMA random value from a Gamma distribution Syntax GAMMA lt real expression gt lt real expression gt lt stream gt
130. gt 5 then order Prior D else FIFO Messages with the value in the field Prior gt 5 are ordered in the IL by descending order of Prior The others are put in the order of arrival at the end of the IL LinBatch L ORDER ProcTime A k 10 OrdBatch G IF LL IL_LinBatch gt k and F_Process gt 0 THEN BEGIN SENDTO Process k k 1 END Process R STAY ProcTime INIT TSIM 200 ACT Arrival 0 Process 10 Messages parts that need different times to be processed at Process field ProcTime must be ordered in increasing order of the process time to optimize the processing This is done by batches of 10 The node LinBatch produces this ordering When the arriving messages make a queue of 10 and Process is idle the queue is sent in the attained order to the node Process See SORT procedure section 7 19 7 16 PAUSE stops the execution Syntax PAUSE It is used to stop the execution of a simulation run The user can restarts the simulation by pressing any key This procedure can be used in nodes of any type 7 17 PUTFEL adds an event to the Future Event List Syntax PUTFEL IA BI lt node name gt lt time gt lt index gt lt parameter gt It is used to put an event in the FEL The parameters of the instruction are the elements fields of the event to be aggregated 92 CHAPTER 7 PROCEDURES e lt node name gt is the name of the node which the event points to e lt time
131. gt is a real expression whose value is the time of the event e lt index gt is the index of the node It must be an integer value e lt parameter gt is the event parameter an integer value from 0 to 255 The element is aggregated to the FEL keeping the ascending order of time If there is one with exactly the same value put in lt time gt it is put After A or Before B of it according to the first parameter See EXTFEL procedure section 7 8 This procedure can be used in nodes of any type 7 18 RETARD produces a delayed function from a given func tion of time Syntax RETARD lt order gt lt delayed output gt lt delay gt lt input gt It is used to generate values delayed and smoothed of an time dependent variable lt order gt is a number from 1 to 30 that indicates the order of the retard lt delayed output gt is a variable that was declared of RET type lt delay gt is a real parameter lt input gt is a real expression The procedure may be used only in a type C node so that when the node is active it is processed repeatedly at small intervals of time As the lt input gt variable or expression takes successive values the values of the lt delayed output gt in each repetition tend to approach with certain lt delay gt those of the lt input gt The form of approach depends on the lt order gt of the RETARD For low order the output is the input smoothed For higher orders the output is more and more lik
132. he EL to release them together TITLE puts title to an experiment o TSIM sets duration to the simulation run o o o UNLOAD releases memory used to import DBASE IV table USE defines the quantity of resource to be used PROCEDURES 7 1 7 2 73 7 4 7 5 7 6 7 7 7 8 7 9 N N NNNNNNN O ON MD TF UANG O 7 7 20 7 21 7 22 7 23 7 24 7 25 7 26 ACT schedules a future activation ofanode 0 BEGINSCAN repeats the scanning of a list o o BLOCK blocks future events of release at a type Rnode CLRSTAT re starts the gathering of statistics o o DEACT deactivates anode o ee DEBLOCK suppresses blocking of node 0 o o ENDSIMUL ends the simulation at the end of the actual event EXTFEL extracts an event from the FEL 0 o FIFO puts the message at the end of the IL of a L type node FREE frees a resource 2 LIFO puts the message at the beginning of the IL ofa L type node MENU calls the Run Interactive Menu 2 00 00 20 000 METHOD sets the method of integration ina C type node NOTFREE inhibits the release of a resource 2 o o ORDER puts the message in the IL of a L node in a given order PAUSE stops the execution ee PUTFEL adds an event to the Future Event List RE
133. he GLIDER system provides different types of nodes that differ in the activation and message processing They are summarized in the Introduction This chapter gives a detailed description and examples In the following we refer to GLIDER common instructions and procedures to instructions and procedures that can be used in any type of node In general are instructions or procedures whose action does not depend on the message being processed They are ACT BEGINSCAN BLOCK ASSI CLRSTAT DEACT DEBLOCK DBUPDATE DO EVENT DONODE ENDSIMUL EXTFEL EXTR FILE FREE GRAPH INTI IT LOAD MENU NT OUTG PAUSE PUTFEL REL REPORT SCAN SORT STAT STOPSCAN TAB TITLE TRACE TRANS TSIM UNLOAD UNTRACE UPDATE USE BEGINSCAN and STOPSCAN are included here because they can be used in any nodes as part of the associate instruction of SCAN The admissible Pascal and GLIDER instructions functions and procedures are listed in chapters 6 7 and 8 4 1 I Input type nodes This type of nodes are used to simulate entrance of items to the system An I type node creates messages and sends them to the successor nodes It has neither EL nor IL 4 1 1 Code It may contain Pascal instructions functions and procedures GLIDER common instructions and procedures GLIDER functions and the GLIDER instructions SENDTO and COPYMESS 4 1 2 Activation It may be activated only by an event that points to the node and only during the first scanning of the net
134. he TankCar to Travel When the Further he Travel to the place in which the Tank is finishes the Level is lowered in a quantity corresponding to the volume of the TankCar T e TankCar is eliminated and the SendTankCar system may be activated again if Level gt 3 There is an hourly Inspection that puts Alarm to TRUE when it finds the Level less than 2 Then the Recovering process begins by decreasing the rate of outflow until the 3 2 is reached Level NETWORK Tank C Level KQLevel FEntry TIME KOLevel Level IF Alarm OR Recovering THEN KOLevel 0 0018 ELSE KOLevel 0 0030 IF Level gt 3 0 AND Send THEN BEGIN ACT SendTankCar 0 Send FALSE END SendTankCar A Travel CREATE TankCar BEGIN VTankCar UNIF 15 3 18 0 SENDTO Travel END Inspection A Tank 0 Update Level IF Level lt 2 0 THEN BEGIN Alarm TRUE Recovering TRUE END IF Level gt 3 2 THEN Recovering FALSE ACT Inspection 3600 Travel R RELEASE BEGIN Level Level VTankCar KQLevel SENDTO Exit Send TRUE END 4 7 C CONTINUOUS TYPE OF NODES 45 STAY TravelTime Exit Gra A 22 IT 15 GRAPH O 86900 BLACK TIME 6 1 WHITE Level 6 0 Alt O 10 GREEN INIT ACT Tank 0 ACT Inspection 0 ACT Gra 0 TSIM 86400 TravelTime 240 Travel MAXREAL DT_Tank 1 0 Level 2 0 KQLevel 0 03 1 MeM KOLevel 0 0035 1 Seg
135. he scanning of a list Syntax BEGINSCAN It is used to re start the scanning of the list being processed usually after the list has been altered When this instruction is executed the scanning of the list starts again from the beginning The user should be careful in using this procedure lest a loop may happen If the BEGINSCAN is executed continually during the scan of a non vanishing list a loop will result This procedure can be used in nodes of G type and in the associated instruction of SCAN Example Ent I COPYMESS 10 BEGIN Age UNIFI 1 100 SENDTO CheckAge END SENDTO CheckAge CheckAge G Egress A 0 SCAN EL_CheckAge Points IF 0_Age gt A THEN BEGIN PointOld Points A O_Age END TRANS EL_CheckAge PointOld A EL_Egress LAST BEGINSCAN INIT ACT Ent 0 7 3 BLOCK BLOCKS FUTURE EVENTS OF RELEASE AT A TYPE R NODE 85 DECL VAR A INTEGER Points PointOld POINTER MESSAGES Ent Age INTEGER Messages persons that arrive to CheckAge are sent to Egress by decreasing order of the field value Age 7 3 BLOCK blocks future events of release at a type R node Syntax BLOCK lt node name gt It stops the creation of events in the node Those events that would activate the node and are already in the FEL are put in suspended state their SU parameters are set TRUE so that they are not executed although their execution time are less than TIME If the node to block is alread
136. his instruction can be used in any type of node Example Aa FOR I 1 TO 3 DO FILE Arxm I Azz 8 2 Chi I 2 BLI 5 1 Azz INIT ACT Aa 0 Azz 99 Chi J ASSI B 1 3 19 20 21 The file Arxm if written only for one execution of node Aa will contain I Azz chi I BLT Azz Me 100 00 J 1 19 0 101 00 J 2 20 0 102 00 J 3 21 0 9 9000000000E 01 9 9000000000E 01 9 9000000000E 01 See example 5 GLIDER examples book for a file to be used with the Graphic option 6 11 GRAPH draws graphics during a run Syntax GRAPH lt initial time gt lt final time gt lt background color gt lt title gt TIME lt format gt lt color gt lt list of variable descriptors gt It is used to display graphics during the simulation run When executed for the first time it constructs the axis reference lines numbers on the axis displays the names given to the variables and scales and marks the initial values of the variables to be graphed In the following executions it adds a new point to the curves of the variables being graphed and unites the points to the the already displayed curves lt initial time gt and lt final time gt are two real numbers indicating the simulation time in which the graphic starts and ends respectively lt background color gt is the color that is to be assigned to the background lt title gt is a string of characters without or If it is
137. in the list s deviation e time that the list remained empty e For the E types nodes the mean time in the system of the messages destroyed in the node and its deviation e For the used time of the resources and the requested variables the statistics given are e mean t and deviation of the variables as a function of time Example ifa variable take the values 2 at time 0 5 at time 4 4 at time 5 7 at time 8 and remain 7 to the end time that is 12 then e mean is 4 0 24 5 4 5 8 5 44 12 8 7 12 0 4 4166667 e maximum and minimum values e mean v and deviation of the values attained for the variable Example In the above example this mean is 2 5 4 4 7 4 4 5 e actual final value After the statistics the Final Menu is displayed 10 8 Final Menu R Repeat statistics C Continue M Menu F Frequency tables G Graphic R The system asks for a file to put the statistics It may be CON to use the screen again LPT1 for the printer or any file indicated by the user e C Continue to the next menu that will be the Initial Menu again to continue the simulation with additional time or to repeat the run with possible modifications From this it is also possible to quit the simulation e M Call the Run Interactive Menu F To display frequency tables e G to display a graphic for the data filed with the FILE instruction during a simulation run When the option
138. in the order in which they appear in the SELECT and according to the value of the field Size it sends them to Proc1 or Proc2 2 Divide D IF Good THEN SENDTO FIRST Pile ELSE SENDTO Garbage 42 CHAPTER 4 SYSTEM PREDEFINED NODES 4 6 E Exit type nodes These nodes destroy messages The messages in the EL are processed The code in the node is executed and the messages are destroyed The node is activated during the scanning of the network if the EL is not empty 4 6 1 Code It may contain Pascal instructions functions and procedures GLIDER common instructions and procedures GLIDER functions and the GLIDER instructions SENDTO CREATE and DEASSEMBLE 4 6 2 Activation It is activated by an event that refers to it or during the scanning of the network ifthe EL is not empty 4 6 3 Function 1 The EL is scanned from the beginning to the end 2 For each examined message the values of the fields pass to the field variables and the code is executed 3 If there is a SENDTO instruction the fields of the message are updated and the message is sent to other node Otherwise the message is destroyed and the used memory may be re used 4 6 4 Relation with other nodes An E type node must have predecessors and may have successors 4 6 5 Indexes If a multiple E type node is activated the nodes are executed successively The value of the variable INO corresponds to the node being processed 4 6 6 Examples LE The m
139. ined for the values given in the set of pairs e STAIR the function value corresponding to an intermediate value of the argument is the corresponding to the more near value of the arguments in the set of values lesser than the given argument i e the function is supposed piecewise constant and continuous from the right e POLYG a linear interpolation is used e SPLINE a cubic spline interpolation is used 2 7 TABLES 25 e FREQ is not an interpolation method The value of the function is taken at random among the possible values of the first element of each pair The second element is interpreted as proportional to the probability of the corresponding first value lt argument type gt and lt function type gt may conform with the following table argument value DISC enumerate or real enumerate or real STAIR real real POLYG real real SPLINE real real FREQ enumerate or real real gt 0 lt maximum number of points gt is a positive integer that indicates the maximum number of pairs of values that define the function In 3 3 the assignation of the set of pairs of values to a function is described Example GFUNCTIONS Temp POLYG REAL REAL 8 pH SPLINE REAL REAL 12 Price STAIR REAL REAL 9 CarTyp FREQ CarType REAL 8 Cost DISC Size REAL 5 2 7 TABLES In order to display statistical results in the form of frequency tables and histograms the names of the tables must be declared The header of the decl
140. ing from the first message Each message is examined the values of the fields are passed to the corresponding field variables and the user code is executed After this execution if the message was not extracted the fields are updated to the values of the field variables that could have been changed and the scanning continues 3 If in the above process a SENDTO instruction is executed the fields are updated the message is extracted and sent to the indicated list s or successor node s The scanning of the EL continues 4 If a STOPSCAN procedure is executed the scanning is stopped and the process of the node finishes However it may be re started during the same event if the scan of the network activates again the node STOPSCAN is used for instance if the sending of further messages depends on the changes caused in other nodes by the actually sent message 5 If a BEGINSCAN procedure is executed the scanning begins again from the first element This may be useful if the sending of a message change the sending conditions of the already examined messages Unwise use of this procedure may cause a loop 6 Note that the sending of message from a G type node must be explicitly ordered by a SENDTO instruction To send a message a SENDTO must be executed one and only one time for the examined message 4 3 4 Relation with other nodes A G type node must have some predecessor and some successor If the predecessor is a L type node the
141. ing of a key If this is C or c the StartSearch node is activated and the simulation continues The node Result is scheduled for a new activation 14400 units of time afterwards If other key is pressed the simulation ends 7 8 EXTFEL extracts an event from the FEL Syntax 88 CHAPTER 7 PROCEDURES EXTFEL lt node name gt lt time gt lt index gt lt event parameter It is used to extract an event from the Future Event List Parameters of the instruction are the elements fields of the event to be extracted lt node name gt is the name of the node which the event points to It must be explicitly indicated lt time gt is a real expression whose value is the time of the event If it is negative it is not taken into account lt index gt is the index of the node If it is 0 it is not taken into account lt parameter gt is the event parameter If it is 0 it is not taken into account This procedure can be used in nodes of any type The first event if any found with the specified values is destroyed and used memory released Example Avenue R Exit Accident A EXTFEL Avenue TimeExit 0 0 The first event that schedules the exit of the IL of Avenue that has an scheduled exit time equals to TimeExit is eliminated 7 9 FIFO puts the message at the end of the IL of a L type node Syntax FIFO It is used to add a message to the end of the IL of aL type node The first message in the EL of the L ty
142. io Acosta 1991 1 Gerardo Rojas 1991 Henry Reinoza 1992 16 Maria Davila 1992 Mayba Uzc tegui 1992 24 Segundo Quir z M Sc 1992 15 Liliana Capacho 1992 Dominique Tineo 1992 Hungr a Berbes 1993 Tania Zambrano M Sc 1993 26 Mauricio Jer z M Sc 1993 Esperanza D az 1993 3 Kay Tucci 1993 23 Francisco Palm 1994 14 Gilberto Gonz lez 1994 Ter n Osvaldo M Sc 1994 19 Ricardo Guanieri M Sc 1994 Margarita Molina M Sc 1995 And with the research training projects of the following students Kay Tucci 1993 Tania Jim nez 1994 13 Gilberto Gonz lez 1994 Rafael Tineo 1996 Dante Conti 1996 Marisol Benitez 1996 Financial support were obtained from the C D C H T Comittee for Scientific Humanistic and Technological Development of the Andes University M rida Venezuela for the period 1992 1994 project E 122 92 and 1996 1998 project 1 524 95 AA 11 2 How to get the GLIDER The software for using the GLIDER and a User s Manual in Spanish or in English is available from Carlos Domingo IEAC FACES Universidad de los Andes M rida Venezuela email carlosd ula ve or from Giorgio Tonella CESIMO Facultad de Ingenier a Universidad de los Andes M rida Venezuela email cesimo ula ve GLIDER is available in two versions a commercial and a student version for MS DOS or Unix operating systems 117 118 CHAPTER 11 DEVELOPMENT OF GLIDER The softwar
143. is a simple one an the event parameter is 0 e line RRRAAREKEAAAEEAEEDDDD gt D gt gt gt gt gt gt gt gt gt Indicates the beginning of an event Its number e node in the NETWORK and the index IEV is indicated Then the name of the node ly activated is shown e procedures executed in the activation are indicated he trace displays the content of the FEL It only has the event scheduled by the ACT instruction in the INIT section This event is an activation of the node Entry at TIME 0 The index of the event is 1 and the event parameter is 0 The EVENT 1 that activates the node Entry at time 0 starts adding other to the F event number 1 next activation unction EL for the future time 0 353 this number comes from the EXPO 1 4 EXAMPLE 1 SIMPLE SERVING SYSTEM 9 A message numbered 1 that was generated at Entry is added to the EL of the node Window that previously had length LL equal to 0 Notice that the messages generated in a node contains a sequential number and the name of that node Following the scanning of the network the node Window is activated The message 1 generated at Entry is examined then extracted from the EL An event of type 2 activation of node Window is put into the FEL to schedule the end of service at time 4 409 The extracted message is added to the IL of the node Window Three events of type 1 arrivals happen at times 0 353 0 888 and 4 108 These are intercalated in th
144. it The value assigned to Path 2 3 is Canned_Food as the third stage of the second client Texts between are comments to explain the data 6 3 COPYMESS makes copies of a message Syntax COPYMESS lt integer value lt associated instruction gt This instruction produces a number of copies of the message that is being processed equal to the value of lt integer value gt that must be greater than zero and for each copy executes the lt associated instruction All fields of the original are copied 6 4 CREATE CREATES A MESSAGE 59 The lt associated instruction gt must have a SENDTO instruction to dispose of the copy Before it instructions can be used to change the values of the fields To do this the names of the 0_ lt fields gt must be used The original message must be processed through instructions outside the lt associated instruction gt before or after the COPYMESS If it is not sent to a node it will be lost The global control variable ICOPY takes the value of the generated copy Its value is not recorded in the copied message If the programmer wan and the value of ICOPY must be passe COPYMESS can be used only in G s to keep it a field must be defined in the message for this purpose to each copy in the lt associated instruction 1 D nodes and in the RELEASE instruction of an R node Examples 1 COPYMESS N_Offices BEG SENDTO Office 1 N Nc ICOPY 1 SENDTO Office nc END
145. ith associated instructions are in general forbidden except in the case of the associated instruction of a RELEASE and STATE instructions lt nest of constants gt is a set of simple INTEGER REAL CHAR or STRING constants in a nest as it is used in PASCAL to give values to indexed constants The whole set is included within its elements are constants or successions corresponding to the successive values of the first index Each succession is included within Each is formed by constants or successions corresponding to the successive values of the second index etc Successions and values are separated by commas Example the array M of 3 indexes of dimension 2x3x3 formed by the two matrices of 3x3 55 Ro Pon wno ome nwo om in which the first index that indicates the matrix the second the line and the third the column is represented by 4 5 0 7 6 2 1 4 3 1 0 1 3 3 8 9 6 9 The element M 2 2 3 has the value 8 lt assignative instruction lt expression gt lt real expression gt lt integer expression lt logical expression lt real variable gt lt integer variable gt lt boolean variable gt lt character variable gt are defined as in PASCAL GLIDER functions may be used in the same way as PASCAL functions Some of the instructions and procedures see Chapters 6 and 7 may be used in any node They are called common instructions and procedures
146. ity 4 4 5 Indexes Multiple nodes are processed successively when the node is activated during the scanning of the network The INO variable takes the value of the index of the processed node If the multiple node is activated by a departing event only the departing part system produced or RE LEASE of the node with the index of the event is processed 4 4 6 Examples 1 Disposal R INIT Disposal MAXREAL The node Disposal enters any quantity of messages compatible with memory available in its IL They may be extracted by a REL instruction in other node 2 Crane R Base RELEASE BEGIN Transported TRUE NOTFREE SENDTO Base END STAY GAMMA Travel_T Dev_T If the Crane is free capacity 1 is assumed a message box takes it it uses the resource for a time took from a GAMMA distribution When this time is over the boolean field Transported is put to TRUE and the message is sent to Base without freeing the resource This must be freed by a REL instruction 3 Sea R STAY FTravelTime VesselType INIT Sea MAXREAL The messages vessels enter the resource Sea of infinite capacity and remain there for a time given by a function FTravelTime that depends on VesselType 4 5 D DECISION TYPE NODES 41 4 5 D Decision type nodes This type of node selects messages from predecessor nodes and sends them to successor nodes D type nodes have an EL for each predecessor Some messages are taking
147. lds gt This instruction is used to load values in a DBASE IV table into arrays that can be managed for the GLIDER program The fields of the lt table gt indicated in the lt list of fields gt are stored in a series of arrays named lt table gt lt name of field gt that were generated by the system by means of the information of the DBTABLE declaration This instruction can be used in nodes of any type See declaration DBTABLE 2 8 instruction LOAD 6 14 and examples in section 2 8 6 15 NT schedules a new activation of the node to a future time Syntax NT lt real expression gt This instruction is used to activate the node in which it appears at a future time given by the current value of lt real expression gt When executed an event is put in the future event list FEL with e The node number equal to the number of the node being executed e An index equal to the current value of INO 1 for single nodes 1 2 3 for successive executions of a multiple node e Even parameter equal to the current value of EVP e Time equal to the current value of lt real expression gt When the node is multiple the instruction may be executed many times In each execution an event is entered in the FEL The instruction can be used in any node except of C type See instruction IT 6 13 and procedure ACT 7 1 Example Signal I IF TIME lt 1999 THEN NT 1999 ELSE WRITELN This is the last signal
148. least an ACT procedure to activate one node of the network to start the simulation In the example the node Entry indicated in the first argument will be activated at a time equal to the time of the initialization that is 0 by default plus the value of the second argument also O in this example Thus it is activated at the beginning of the simulation Values are assigned to the parameters Tba MeanWait and StaDev Complete algorithms may be included in this section In this section may also be assigned capacities to R nodes values to user defined functions frequency table parameters and database tables See Chapter 3 for details e DECL section contains the declaration of some elements of the program introduced by the user These names must be different of the reserved or system words see Chapter 9 The subsection VAR contains the declarations of the variables The subsection STATISTICS may contain node names and variable names from which statistics are wanted In this case only node statistics are requested Other declarations of data corresponding to the base language may be done here types constants records arrays sets files The procedures and functions declared and programmed by the user must be also included in this section Function defined by pairs of values a special feature of the GLIDER language the data base tables frequency tables and the structure of the messages must be also declared here See
149. led When all messages are compared the second message in the EL is taken as the new comparing message which is compared with those that follow it The process is repeated so that all the possible comparisons are made If at any point of the process a number of candidates reach the value expressed by lt integer value gt the assemble is successful Then the assembled messages are taken out of the list and the lt associated instruction gt is executed The whole process is then repeated to see if another successful assemble group of the required size is possible with the remaining messages If the parameter ALL is used there is not limit for the assembled set 6 2 ASSI ASSIGNS VALUES TO ARRAYS AND MULTIPLE NODES 57 If the lt logical expression gt is reduced to the constant TRUE the messages are unconditionally assembled up to the specified number or all the messages if ALL is used If there is not successful assemble at all nothing is done and the lt associated instruction gt is not exe cuted If the function EQUFIELD lt field gt is used instead of the lt logical condition gt the messages which have the same values on that field are assemb In all cases it is assumed that all th conditions Which message is the representant and t e ELIM indicates that the representant is the first of t are eliminated ed em essages in the EL have the fields that are used by the assembling e fate of the assem
150. lt lt variable gt lt node gt range lt nest of constants gt This instruction is used to assign values to arrays of any number of indexes or capacity to multiple nodes lt variable gt is a name of an indexed variable lt node gt a name of a indexed node range is a range of indexes within the range defined for the node or variable ASSI can be used in any type of node Examples 1 Let Alpha be an array of CHAR of one index The instruction ASSI Alphal2 4 Ca r s assigns the values a to Alpha 2 r to Alpha 3 s to Alphal4 If r was declared r ARRAY 1 3 2 4 1 2 OF INTEGER then the instruction ASSI r 1 2 2 4 1 2 3 3 5 6 8 9 C 6 7 0 1 9 2 assigns the values r 1 2 1 3 r t 2 2 3 r 1 3 1 5 r t 3 2 6 r 1 4 1 8 r t 4 2 9 r 2 2 1 6 r 2 2 2 7 r 2 3 1 0 rf2 3 2 1 r 2 4 1 9 r 2 4 2 2 the instruction does not assign values to the elements r 3 2 1 rl3 2 2 r 3 3 1 r 3 3 2 r 3 4 1 r 3 4 2 2 The following instruction assigns the paths of 3 clients in a supermarket ASSI Paths 1 3 1 5 Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 A Client 1 Entry Fruits Bread Beverage Exit Client 2 Entry Bread Canned_Food Exit gt Client 3 Entry Pastry Bread gt Fruits Ex
151. manual GLIDER and Pascal reserved words are in upper case letters user identifications are in lower cases with normally the first letter in upper case NETWORK Depart I Railroad Coaches UNIFI 16 20 IT 45 Railroad R Destination 22 STAY 25 Destination E WRITELN A train arrives at time TIME Its length is Coaches PAUSE 1A complete set of examples can be found in the GLIDER examples book or in the directory DEMOS of the GLIDER disk 2The GLIDER and PASCAL reserved words are all in capital letters In the case of user words only the first letter is capital 2 CHAPTER 1 INTRODUCTION INIT TSIM 1300 ACT Depart 0 DECL MESSAGES Depart Coaches INTEGER STATISTICS ALLNODES END The program has the following sections e Heading section with title and explanations e NETWORK section that describes the nodes subsystems and the relations among them e INIT section that sets the simulation time and the node to be firstly activated at simulation start It may include other initializations see Chapter 3 e DECL section that declares the structure of the messages and the statistics required It may include declarations of other variables and elements of the program see Chapter 2 It follows a description of the NETWORK section and its functions After each node name follows a letter between parenthesis indicating its type and the successor node to which messages can be sent Depart is a
152. mingo C Fargier M E Mora J Rojas A Tonella G 1994 Modelo de la Econom a de Venezuela basado en Conceptos Microecon micos Model of Venezuelan Economy based on Microeconomic Con cepts XII Latin America Meeting o Econometric Society August 1994 11 Domingo C 1994 Modelo de Simulaci n de Flujo de Crudos y Puerto Petrolero usando el Lenguaje GLIDER Simulation Model of Oil Flow and Shipment using GLIDER Language IEAC Universidad de los Andes M rida Venezuela 2 Hern ndez C 1993 Ense anza Programada para el GLIDER Trabajo Especial de Grado Pro amp grammed Learning of GLIDER Language Thesis Escuela de Ing de Sistemas Universidad de los Andes M rida Venezuela Tutor G Tonella 121 122 20 21 22 23 24 25 26 BIBLIOGRAPHY Jim nez T 1994 Ambiente Gr fico para el Lenguaje de Simulaci n GLIDER sobre el Sistema X Windows The Graphical Environment for the GLIDER Language using the X Windows System Pasantia de Investigaci n Escuela de Ing de Sistemas Universidad de los Andes Tutor M Sananes Palm F 1993 Prototipo de Lenguaje GLIDER para Manejar Problemas de Valores Iniciales en Derivadas Parciales Trabajo especial de grado GLIDER Language Prototype to handle Initial Value Problems in Partial Differential Equations Thesis Escuela de Ingenier a de Sistemas Universidad de los Andes M rida Venezuela Tutors G Tonella a
153. n to the simulation run Syntax TSIM lt real expression gt It is used to set the simulation duration The GLIDER system variable TSIM is set to the value of lt real variable gt and the end of the simulation is scheduled for a future time equal to TSIM The end of the simulation can also be done using the ENDSIMUL instruction If none of these instructions is found an error condition arises If many ENDSIMUL instructions are present the first one executed will end the simulation If many TSIM instructions are executed the last executed defines the simulation time This instruction can be used in nodes of any type and in the INIT section 6 29 UNLOAD releases memory used to import DBASE IV ta ble Syntax UNLOAD lt DBASE IV table name gt lt list of table fields gt It is used to eliminate from the dynamic memory the data array corresponding to a DBASE IV table The freed space may be used by the running program lt DBASE IV table name gt is the name of a table declared in DBTABLES declaration lt list of table fields gt is a list of fields of the table that correspond to the arrays to be deleted This instruction can be used in nodes of any type See examples in section 2 8 6 30 USE defines the quantity of resource to be used Syntax USE lt real expression 82 CHAPTER 6 INSTRUCTIONS It is used to define the quantity of resource to be used for a message The instruction assigns the value of lt r
154. nd procedures 4 9 1 Code It may contain Pascal instructions functions and procedures GLIDER common instructions and procedures GLIDER functions and the GLIDER instruction SENDTO CREATE DEASSEMBLE ASSEMBLE and SYNCHRONIZE 4 9 2 Activation It is activated by an event that refers to the node or during the scanning of the network this is the difference from an A type node 4 9 3 Function The activation consists in the execution of the code All management of messages must be explicitly indicated in the user s code by means of Pascal or GLIDER instructions and procedures 4 9 4 Relation with other nodes Predecessors and successors are only required if the node must receive and send messages 48 CHAPTER 4 SYSTEM PREDEFINED NODES 4 9 5 Indexes When it is activated all the nodes are executed The variable INO has the number of the node being executed Chapter 5 NETWORK The NETWORK section of a GLIDER program describes the relationships among the subsystems and the code that simulates their behavior In what follows the general rules to write this section and the way in which it is processed are described 5 1 Defining a node The node has two parts a heading part and a code part The structure is lt heading gt lt code gt 5 1 1 Heading This part declares the name the type the successors and the local variables The heading has the following structure lt name gt lt type gt lt index ra
155. nd C Domingo Quir z S 1992 Dise os Experimentales en Simulaci n Tesis de Maestr a Experimental Designs in Simulation M S Thesis in Statistics TEAC Universidad de los Andes M rida Venezuela Julio de 1992 Tutor C Domingo Reinoza M 1992 An lisis de Lenguajes de Simulaci n para Control y su Posible Adaptaci n al Lenguaje GLIDER Trabajo especial de grado Analysis of Control Simulation Languages and Adap tation to GLIDER Language Thesis Escuela de Ingenier a de Sistemas Universidad de los Andes M rida Venezuela Tutor G Tonella Sananes M 1992 Editor Gr fico del Lenguaje de Simulaci n GLIDER Documento de Dise o Graphic Editor of GLIDER Simulation Language Design Report Publicaci n Cesimo IT 9202 Cesimo and IEAC Universidad de los Andes M rida Venezuela Febrero de 1992 Sananes M 1992 Instructivo del Uso del Editor Gr fico del Lenguaje de Simulaci n GLIDER Cesimo and IEAC Manual for Using of Graphic Editor of the GLIDER Simulation Language Universidad de los Andes M rida Venezuela Febrero de 1992 Ter n O 1994 Simulaci n de Cambios Estructurales en Lenguaje GLIDER Tesis de Maestr a en Estad stica Aplicada Simulation of Structural Changes in GLIDER Language M S Thesis in Applied Statistics TEAC Universidad de los Andes M rida Venezuela Tutor C Domingo Tonella G y C Domingo 1990 GLIDER a New Simulation Language in
156. nge gt lt list of successors gt lt LABEL lt list of labels gt gt lt VAR lt declarations of local variables gt gt Items between may be omitted e lt name gt is an identifier see Chapter 2 that indicates the name of the node It is also the declaration of the node e lt type gt is a letter that designs the type of the node See Chapter 1 and Chapter 4 If omitted the first letter of the name is assumed to describe the type e lt index range gt is a range indicator of the form 1 lt positive integer gt If omitted the node is assumed simple e lt list of successors gt is a list of node names They are the nodes to which messages may be sent Multiple nodes must have an index If the list is omitted and the node needs a successor the system tries to see if the following node is a feasible successor If so it will be the successor Otherwise an error condition occurs e lt LABEL lt list of labels gt gt If labels are used in the code they must be declared here the list is formed by numbers or identifiers separated by commas The labels are local to the node and all must be used e lt VAR lt list of declarations of local variables gt gt This is to declare local variables as in the VAR part of the section DECL see 2 3 49 50 CHAPTER 5 NETWORK Examples Ingoing Crane R 1 3 Belt INO VAR Vel real MaxWeight ARRAY OF REAL Control G Street LABEL 1 EndCont 5 1
157. nodes Before this sending the fields of the message are updated at the values of the field variables After the sending of the message the capacity of the node is updated adding the value of the USE field to the free capacity variable F_ lt node gt and subtracting the value of USE to the used capacity variable U_ lt node gt This resource freeing can be inhibited if a NOTFREE procedure appears in the associated instruction of the RELEASE instruction This is used in applications in which some items abandon the resource but this requires an additional time to be available again The freeing is made elsewhere by a FREE procedure at a latter time The part of the code that pass the messages to the EL accepting function is executed when the EL is not empty It examines the messages in the EL starting from the first For each examined message the fields are passed to the field variables and the user s instructions in this part are executed One of them may be a STAY lt expression gt instruction The required amount of resource USE field is compared with the available resource F_ lt node gt variable If USE is greater than F_ lt node gt the message remains in the EL and the scanning of the EL continues Otherwise the message is extracted the event of its future departing is scheduled if there was an STAY instruction and the message is added at the end of the IL The capacity of the R node is updated subtracting the value of
158. nstructions The user have to assign a file name to this variable in the INIT section see chapter 3 This instruction can be used in nodes of any type See example 18 GLIDER examples book 6 21 SCAN scans and processes a list of messages Syntax SCAN lt list name gt lt pointer gt lt associated instruction gt This instruction is used to examine lists of messages to point modify and extract messages lt list name gt is a name of an IL or EL It may be of any node lt pointer gt is a variable declared as POINTER When executed it scans the list indicated For each scanned message the fields are passed to the 0_ lt fields gt and the lt associated instruction gt is executed Then the 0_ lt fields gt are passed to the fields of the message The scanning may be suspended when a STOPSCAN instruction is executed Otherwise it continues until the end of the list is reached If a lt pointer gt is included it will contain a point to the last processed message A system generated pointer points to the previous message in the list This allows the user to manage the pointed message If during the execution of the lt associated instruction gt a SENDTO instruction is executed the message in process is extracted and sent to the place indicated by the SENDTO The scanning continues This instruction can be used in nodes of any type Examples 1 Heating A Process IT 10 SCAN EL_Line BEGIN O_Temp O_T
159. ode to set the integration method of the differential equations in the node If RKF is used the method will be a Runge Kutta method of fourth order with a fifth order calculation to estimate the error Runge Kutta Fehlberg The integration path is changed according to the error If RK4 is used the method will be a Runge Kutta of fourth order If EUL is used the method will be the simple Euler method of the first order RKF is the more exact and slower EUL is the less exact and faster EABS and EREL are used with RKF method of integration to change the integration step when the error in one step exceeds respectively in absolute or relative value the values of these variables Default options are EABS 0 00001 EREL 0 0001 This procedure may be used only in C type nodes If used it must be put at the beginning of the code Example Growth C METHOD RK4 Size K_Growth 1 Size MaxSize Size Quantity MaxQuant K_Incr Quantity Biomass SpGr Size Quantity HeatEffect C METHOD EUL K_Growth K_Growth_Max Ctg Temp K_Growth K_Incr K_Incr_Max Cti Temp K_Incr It is supposed that K_Growth and K_Incr growth very slowly with Temp so that a less exact but more fast integration method may be used 7 14 NOTFREE inhibits the release of a resource Syntax NOTFREE It is used to suppress the release of capacity by the messages going out of the IL of a R type node This procedure may be use
160. of values frequency tables data base tables and needed statistics All user s variables must be explicitly declared as mandatory in Pascal The names assigned to types variables constants functions and procedures are called identifiers They are strings of at most twelve characters including letters numbers and the sign _ The first character in the identifier must be a letter GLIDER is case insensitive 1 so Water_Temp and WATER temp are the same variable A declared identifier must not duplicate any system or previously user defined identifier See Chapter 9 for a list of system defined identifiers The declaration section begins with the separator DECL as the first word of a line Identifiers are declared in the following subsections of the DECL section according to their element class 1 TYPE types 2 CONST constants 3 VAR variables 4 NODES nodes 5 MESSAGES messages 6 GFUNCTIONS user s functions defined by values 7 TABLES frequency tables 8 DBTABLES tables from a data based system 9 PROCEDURES user s built procedures and functions 10 STATISTICS required from nodes and variables A declaration consists of the name of the element class one of the above followed by identifier declarations according to the syntax described in the following sections 2 1 TYPE A type declaration specifies to the compiler that a given identifier or name will designate a type of data that may be referred to in the program
161. of the EL is stopped to allow the change in the IL of Street Without the STOPSCAN more than 20 messages would be sent to Street On the other hand if the condition is not fulfilled stopping of the scan avoids unnecessary examination of the EL Eventually future changes in the IL of Street will produce a network scanning an a new activation of Semaf 4 Control G Machine INO SENDTO Machine FREE The message object to be processed is sent to the first free Machine with free capacity If there is no free Machine the message remains in the EL of Control 5 Selection G F Typ Special AND First THEN BEGIN SENDTO Depot BEGINSCAN First FALSE END ELSE IF NOT First THEN SENDTO Depot Among the messages in the EL of Selection there is one and only one with the field Typ Special Only after it pass all the others may pass The boolean variable First is originally TRUE 4 4 R Resource type nodes This type of nodes simulates resources used by the entities represented by the messages A real value called the node capacity is associated to the node The messages in the EL represent entities that demand a certain quantity of that capacity during a certain time The EL is examined and for each message it is checked if the demanded quantity is available If it is so the message is moved to the IL the time of future depart is scheduled in the FEL and the quantity of resource used for the message is subtracted to
162. ompared with the mean length in the last 1000 time units This is given by the GLIDER function MEDL If the difference compared with the mean of the two values is less than 3 the queue is considered stable a new count of statistics begin and the node is blocked Otherwise the last value of the mean is saved in Qma and a new statistical count is initialized for the next 1000 time units Statistics at the end of the run are counted since the beginning of the stable situation This procedure tries to avoid the influence on statistics of the transient produced when starting with a void queue 7 5 DEACT deactivates a node Syntax DEACT lt node name gt It is used to deactivate a node i e to suppress the future event that would turn out it active A typical use is to stop the integration in a C type of node that solve differential equations This procedure can be used in nodes of any type Examples Growth c Diameter KGrowth 1 Diameter DMax Diameter If Diameter gt 50 then DEACT Growth CREATE CutMessage SENDTO Saw While the node Growth is active it computes the change in time according to the shown differential equation logistic growth When the variable Diameter exceeds 50 the process of integration is stopped and a message is created and sent to Saw Warning I IT Week SENDTO Debtor F Number gt Enough THEN BEGIN DEACT Warning ACT Procedure3 0 END E The node Warning produces
163. os and 3 ships that come to be repaired The port has an entry channel in which only a ship at a time is allowed to pass The same channel is used to enter to the piers and to exit once the operation in the port is finished 1 5 EXAMPLE 2 PORT WITH THREE TYPES OF PIERS 13 Model of a Port C Domingo 2 23 96 Ships arrive at a port with interval times with exponential distribution with mean Tbarr ere are 3 types of ships The type is selected from an empirical random distribution by means of a function FTyp According to the type they go to the piers 1 2 or 3 e ships are queued before the entry channel A ship is allowed to pass only if the channel is free and the ship has a place in the pier of its type e time spent in passing the channel is a fixed value TChannel n the pier the ship remains a time taken from a Gamma distribution e mean TPier depends on the type The deviation is 10 of the mean Each ship uses only one position in the pier o the served ships the type 4 is assigned and they are sent to the annel to exit the system ake a frequency table of the mean time in the system xperiment with different serving times in the piers mesa NETWORK Entrance 1 IT EXPO Tbarr ShiTyp FTyp Control G IF F_Pier ShiTyp gt 0 and F_Channel gt 0 THEN SENDTO Channel Channel R Pier ShiTyp Departure RELEASE IF ShiTyp 4 THEN SENDTO Exit ELSE SENDTO Pier ShiTyp STAY TChann
164. ous values t is decided between 0 1 and 0 4 according its marginal probabilities 15 32 for 0 1 and 17 32 for 0 4 f the selected is for instance 0 1 the second value is selected according to the marginal probabilities 3 1 17 for the value 2 0 4 3 17 for the value 5 0 3 1 17 for the value 10 0 f the selected is for instance 5 0 the third value is selected according to the probabilities 4 7 for 15 0 and 3 7 for 18 0 See that the probability of the value 0 1 5 0 15 is then 17 32 7 17 4 7 4 32 as may be see directly e following program computes 32000 random numbers with the frequencies in the array Mul counts the different results and put them in a table Zzz similar to Mul The values in Zzz must be approximately those in Mul NETWORK Ar IT 1 RAND Mul 2 F RANDV_Mul 1 0 1 THEN I 1 ELSE I 2 F RANDV_Mul 2 2 0 THEN J 1 ELSE F RANDV_Mul 2 5 0 THEN J 2 ELSE J 3 F RANDV_Mul 3 15 0 THEN K 1 ELSE K 2 Zzz I J K Zzz I J K 1 Result A WRITELN FOR I 1 TO 2 DO BEGIN WRITELN FOR J 1 TO 3 DO BEGIN WRITELN FOR K 1 TO 2 DO WRITE Zzz I J K 1000 7 4 END END PAUSE ENDSIMUL INIT ACT A 0 ASSI Mul 1 2 1 3 1 2 C 1 3 04 3 03 1 3 2 02 1 03 6 ASSI VAL_Mul 1 3 1 3 0 1 0 4 0 0 2 5 10 15 18 0 ASSI Zzz 1 2 1 3 1 2 COCO 0 0 0 0 0 0 0 0 0 0
165. pArr I ShipType FTypeFreq IT EXPO Tbalord ShipType CREATE Train BEGIN Wears Round TotalLoad Capacity SENDTO Yard END DECL TYPE St Freighter Tanker Barge MESSAGES ShipArr ShipType St Load ARRAY 1 5 OF REAL Displ REAL Train WCars INTEGER Capacity REAL In the node ShipArr messages representing different types of simulated ships are generated The characteris tics fields of the message are ship type five quantities indicating different kinds of loads and displacement In the node TrainContr according to conditions computed by a complex code the decision of sending a message train to a yard is taken 2 6 GFUNCTIONS GLIDER allows to define functions of one variable given by a set of pairs of values points The first element of the pair is the value of the argument it belongs to the domain The second is the corresponding value of the function The type of the argument type of the function and the method of interpolation must be declared This declaration has the heading GFUNCTIONS followed by declarations with syntax lt function identifier gt lt interpolation method gt lt argument type lt function type lt maximum number of points gt lt interpolation method gt indicates the method to be used to compute values for intermediate values of arguments not given in the set of pairs The methods may be e DISC intermediate values are not allowed The function is only def
166. pdated to the time of simulation process goes on until an end condition specified by the user le it through special GLIDER procedures he simulation An event activation fact begins with uled The value of the simulation time do not change during the transformations produced he erred by this element node may cause changes in the values of the variables execution of procedures and message ange conditions that done in these events hese changes it follows a scanning of all the nodes that could be affected by the execution ically until no furt owing event from er he the event indicated in finishes the simulation run The user must be aware of the two ways in which a node can be activated by an event that refers to the node which starts a new event or by scanning of the network during an event 1 2 Types of nodes A summary of the characteristics of he predefined node types is shown in the following list Any node can be activated by an event that refers to it Others not all may be also activated during the network scanning process Some node types ave EL and IL others only EL others none of them When activation is attempted by the scanning process it may be inhibited in certain conditions EL empty Otherwise the code is executed each time that the node is scanned The user can avoid these repetitions by means of special instructions All activation of a node starts a scanning process with the
167. pe node is passed to the end of the IL The IL is formed in the order of arrival FIFO order As this order is the same that the default order in which the EL is processed the FIFO procedure can be omitted unless other order specifications are also used in the same node It may be used only in L type nodes Example LinePile IF Box THEN LIFO ELSE FIFO Messages that have the field Box equal to TRUE are added at the beginning of the IL the others at the end see FIFO procedure 7 9 When they are extracted from the IL in the order of this list those with Box TRUE are extracted in LIFO order that who came last is extracted first as in a pile of boxes After these are the messages with Box FALSE ordered as they arrived 7 10 FREE frees a resource Syntax FREE lt node name gt It is used to release a resource from the R type node that was left by the message without releasing the resource at the leaving time see NOTFREE procedure 7 14 The quantity of resource freed from the indicated node is equal to the actual value of the USE variable The procedure may be executed in any node when processing any message or no message at all However in most usual applications it is executed while processing the message that left the resource without releasing the used capacity In many applications the message has to do other things or await certain time before the abandoned resource become available This procedure can be used in node
168. pe identifier gt STRING lt positive integer number gt If lt positive integer number gt is omitted in type specification for variable declaration the maximum length 255 is assumed i e the word STRING alone is a predefined type identifier Examples TYPE Names STRINGL25 VAR Roll ARRAY 1 1000 OF Names Trademark STRING 10 LongLine STRING Roll is an array of 1000 elements each of them is a string that may contain up to 25 characters LongLine may contain up to 255 characters Trademark may contain up to 10 2 1 5 Procedural types PROCEDURE or FUNCTION types are declared by writing the prototype or heading pattern for a class of procedures or functions i e the set of procedures or function that have the same pattern for parameter list declaration and that return the same type of value in the case of functions The variables declared of these type can take as values names of procedures or function that conform with the prototype i e that belong to the specified class The syntax is lt type identifier gt PROCEDURE lt parameter list gt or lt type identifier gt FUNCTION lt parameter list gt lt returned type gt Example TYPE TyProcess PROCEDURE Material Machine INTEGER VAR Prot Pro2 TyProcess The variables Prot Pro2 can take the name of any procedure with any name conforming with the declared prototype See 2 9 for declarations of procedures and functions in GLIDER 2 2 CO
169. perimental variable of the type e simple variable e element of an array 32 CHAPTER 3 INITIALIZATIONS e name of a type R node e functions given by pairs of values e name of a frequency table When the option read Experiment and continue is selected in the Menu the system displays the values of these variables in the form lt identifier gt lt value s gt and it askes for a file name This file will contain the assignation of the experimental variables in the defined format The order and quantity may be different of those of the declaration in the INIT Example EXPER SIM 6000 A 5 08 Fx 1 3 8 5 2 8 1 Reci 6 0 S 7 able2 0 12 2 5 ENDEXP The program will be run with the assigned values of these variables If the E option in the run interactive menu see section 10 5 is selected the system prompts ENTER NAME OF DATA FILE The user must write the name of an input data file may be CON for the keyboard The file must begin for a line with a title for the experiment and lines follows of assignation like those in the INIT without the characters or For instance Fx 1 3 8 5 2 81 S i 7 Table2 0 12 2 TSIM 6000 END The system reads the data and assigns the values to the variables until the END is found The system display the new values that can be corrected or accepted by the user When accepted the simulation continues Chapter 4 SYSTEM PREDEFINED NODES T
170. put to each N was initialized to 0 Those with the field By_Air are sent to the node Airport the others are sent to Railroad As the node is of E type the original message is destroyed See example 13 GLIDER examples book 62 CHAPTER 6 INSTRUCTIONS 6 7 DOEVENT permits instruction execution only once in the event Syntax DOEVENT lt associated instruction gt DOEVENT is used to avoid repeated executions of an instruction or a set of instructions caused by repeated scanning of the network When this instruction is executed the lt associated instruction gt is only executed in the first scanning of the nodes during an event In a multiple node the effect occurs for all the nodes See instruction DONODE 6 8 This instruction can be used in any type of node Example MainGate G DOEVENT N 0 IF Apt AND IL EL_Work lt 10 THEN BEGIN SENDTO Work N N 1 STOPSCAN END Messages in the EL of MainGate with the field A TRUE are sent to Work one in each revision of the node because of the STOPSCAN procedure see 7 21 This is made so to check the length of the IL_Work The number of messages sent in the event is registered in the variable N The DOEVENT avoids repeated initializations to O in the successive sending 6 8 DONODE prevents instruction execution during network scanning Syntax DONODE lt associated instruction gt DONODE is used when an instruction or a set of instructions must be executed only in
171. r IF LL EL_Ballon_Gate 0 THEN BEGIN NBatch NBatch 1 Complete FALSE Present FALSE TotWeight 0 END END Tour R RELEASE Present TRUE STAY UNIF 50 63 Exit E INIT ACT Entrance 0 NBatch 0 TotWeight 0 Present TRUE Complete FALSE Tour MAXREAL DECL VAR NBatch INTEGER TotWeight REAL Present Complete BOOLEAN MESSAGES Entrance Weight REAL STATISTICS ALLNODES Messages passengers for a balloon are weighted at Tour_Gate While the total weight is less than 930 and Complete was FALSE they are sent to Balloon_Gate When one incoming message cause the weight to exceed 930 the scanning of the EL is stopped Complete is put to TRUE and TotWeight to zero No more passengers can pass the Tour_Gate Then Balloon_Gate can operate if the balloon is present Present TRUE The messages in the EL are sent to Tour Complete and Present are put to FALSE and the batch is counted TotWeight is set to zero to permit the gathering of a new batch of passengers The Tour takes between 50 and 63 minutes When it finishes the passengers went to Outside and Present becomes TRUE 7 22 TAB adds values to a frequency table Syntax TAB lt real variable gt lt table name gt It is used to count a value for a frequency table lt table name gt must have been declared in a TABLES declaration see 2 7 Parameters of the tables must be initialized in the INIT section see 3 4 The actual value
172. rators AND DIV MOD NOT OR XOR 9 14 GLIDER instructions and procedures ACT ASSEMBLE ASSI BEGINSCAN BLOCK CLRSTAT COPYMESS CREATE DBUPDATE DEACT DEASSEMBLE DEBLOCK DOEVENT DONODE ENDSIMUL EXTFEL EXTR FIFO FILE FREE GRAPH INTI IT LIFO LOAD MENU METHOD NOTFREE NT ORDER OUTG PAUSE PREEMPTION PUTFEL REL RELEASE REPORT RETARD SCAN SELECT SENDTO SORT STAT STATE STAY STOPSCAN SYNCHRONIZETAB TITLE TRACE TRANS TSIM UNLOAD UNTRACE UPDATE USE 9 15 Pascal procedures APPEND ASSIGN BLOCKREAD BLOCKWRITE CLOSE CLRSCR DELAY DISPOSE FILEPOS FILESIZE GETDATE GETTIME GOTOXY MAX MIN NEW OPEN READ READLN RELEASE RESET REWRITE SEEK SOUND STR TRUNCATE VAL WRITE WRITELN 9 16 GLIDER functions BER BETA BIN DMEDL DMSTL ENTR ERLG EXPO GAMMA GAUSS LL LOGNORM MAX MAXI MAXL MEDL MIN MINI MINL MODUL MSTL NORM POISSON RAND TFREE TRIA UNIF UNIFI WEIBULL 9 17 Pascal functions ABS ARCTAN COPY cos EOF EXP FILESIZE INT KEYPRESSED LENGTH LN NOSOUND OFS ORD RANDOM READKEY 9 18 COLORS 111 ROUND SEG SIN SQRT TRUNC WHEREX WHEREY 9 18 Colors BLACK BLUE BROWN CYAN DARKGRAY GREEN LIGHTBLUE LIGHTCYAN LIGHTGRAY LIGHTGREEN LIGHTMAGENTA LIGHTRED MAGENTA READ RED WHITE YELLOW 9 19 Pascal constants HEAPORG HEAPPTR HEAPEND 9 20 Other reserved words A or B used in SENDTO TRANS and PUTFEL to indicate if the message is put before B or after A the pointed message in the case of SENDTO or TRANS or the event with the same value of TIME in the case
173. rep2 Education 104000 7 65 SelfEmp Housing 2500 5 66 SelfEmp Food 3060 8 67 SelfEmp Clothing 1200 6 71 SelfEmp Health 1350 6 72 SelfEmp Education 1095 7 When this table is loaded the system pass the values to an array called ConsPatt with two indexes and sizes of 9 rows and 8 columns So ConsPatt Entrep2 Food 92000 2 9 PROCEDURES The user can program functions and procedures as in the base Pascal language Procedure and function declarations must be placed under the heading PROCEDURES of the DECL section In these functions and procedures instructions of the base Pascal language as well as GLIDER functions can be used In addition to the instructions STOPSCAN and BEGINSCAN the following all but IT NT DEACT DOEVENT DONODE common GLIDER instructions and procedures enumerated in Chapters 6 and 7 may be used They are ACT BLOCK ASSI CLRSTAT DEBLOCK DBUPDATE ENDSIMUL EXTFEL EXTR FILE FREE GRAPH INTI LOAD MENU OUTG PAUSE PUTFEL REL REPORT SCAN SORT STAT TAB TITLE TRACE TRANS TSIM UNLOAD UNTRACE UP DATE USE 2Conforming to TurboPascal version 6 0 28 CHAPTER 2 DECLARATIONS However names of nodes lists GFUNCTIONS and database tables cannot be used as formal parameters in the present version This restricts the usefulness of these instructions in procedures Type declarations procedure declarations and function declarations within a function or procedure are not allowed Examples PROCED
174. rious Medium Serious Critical Dis Hurt Infectious Shock Heart Internal MESSAGES Patient Disease Dis Status St REMA REAL GFUNCTIONS Fdisease FREQ Dis REAL 5 Fstatus FREQ St REAL 4 See example 8 GLIDER examples book 6 18 REL takes a message out of the IL of an R type node Syntax REL lt internal list of node R gt lt logical expression gt lt associated instruction gt This instruction is used to extract a message from the IL of a R type node When executed a search starts at the IL of the node looking for the first message for which lt logical expression gt is true If there is not such a message nothing is done If it is found it is extracted from the IL and the lt associated instruction gt is executed If a time of exit is scheduled for a normal release of the resource the corresponding event of the FEL is removed to eliminate the scheduling If there is extraction of message the boolean variable EXTREL is put to TRUE otherwise it remains FALSE The values in the fields of the extracted messages are passed to the corresponding 0_ lt variables gt The lt associated instruction gt must have a SENDTO instruction to dispose of the extracted instruction Before the SENDTO is executed instructions can be used to change the values of the fields To do this the names of the 0_ lt fields gt must be used This instruction can be used in nodes of any type Example NETWORK Entry I
175. riving messages make a queue of 10 and Process is idle the queue is sorted in ascending order of ProcTime and it is send in the attained order to the node Process 7 20 STAT displays the statistics Syntax STAT It is used to display the standard statistics during the simulation run This procedure can be used in nodes of any type Examples WriteStat a IT 100 Statistics are display each 100 units of time The node WriteStat must be activated from outside the first time Rep G IF Reports and EL_Memory gt 20 then STAT Sendto DEC Each time a message with the field Reports equal to TRUE arrive and the queue in node Memory is greater than 20 the statistics are shown 7 21 STOPSCAN stops the scanning of a list of messages Syntax STOPSCAN It is used to stop the scanning of a list EL or IL When used in a SCAN instruction the list is that indicated in the instruction If it is used in a type G node outside a GLIDER instruction the list is the EL of the node This procedure can be used in nodes of G type and within a SCAN instruction in any type of node permitting SCAN Example Test STOPSCAN Example 1 NETWORK Tour_Gate G Ballon_Gate TotWeight TotWeight Weight IF TotWeight lt 930 AND NOT Complete THEN BEGIN SENDTO Balloon_Gate END ELSE BEGIN STOPSCAN Complete TRUE TotWeight 0 94 CHAPTER 7 PROCEDURES END Balloon_Gate G IF Complete and Present THEN BEGIN SENDTO Tou
176. rom a Normal distribution Syntax NORM lt real expression gt lt real expression gt lt stream gt Returns a REAL value of a random variable whose probability function is a normal function with mean equal to the first lt real expression gt and deviation equal to the second lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed The algorithm may produce negative values 8 24 POISSON random value from a Poisson distribution Syntax POISSON lt real expression gt lt stream gt Returns an INTEGER value of a random variable whose probability function is a Poisson function with mean equal to lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 25 RAND random value from a multivariate distribution Syntax RAND lt array gt lt stream gt This is in reality a procedure It is used to generate random variates taken from multivariate random functions The n dimensional random functions are given by an n dimensional lt array gt whose values are an n dimensional frequency table It must be declared of FREQ type and initialized in the INIT section The values of the variables must be declared in a two dimensional arrays one array for each variable In the first row are the successive values of the fi
177. rom dividing two real expressions 2 o e 0 o 8 15 BER random value from a Bernoulli distribution o o o e 8 16 BETA random value from a Beta distribution o e e o 8 17 BIN random value from a Binomial distribution o o e 8 18 ERLG random value from an Erlang distribution 2 o o o e 8 19 EXPO random value from an Exponential distribution o o 8 20 GAMMA random value from a Gamma distribution o o e 8 21 GAUSS random positive value from a Normal distribution o 8 22 LOGNORM random value from a Lognormal distribution o o 8 23 NORM random value from a Normal distribution 2 o o o e 8 24 POISSON random value from a Poisson distribution 2 2 o oo e 8 25 RAND random value from a multivariate distribution o o o e 8 26 TRIA random value from a Triangular distribution o o e 8 27 UNIF random value from a real Uniform distribution o o o e 8 28 UNIFI random value from an integer Uniform distribution o o 8 29 WEIBULL random value from a Weibull distribution o o e 9 RESERVED WORDS 9 1 Message variables 2 1 2 9 2 Event variables 2 aa aaa 9 3 Indexed node variable 2 aaa 9 4 Control and state variables 2 2 o o 9 5
178. rst variable in the second row the successive values of the second variable etc The number of rows is then equal to the number of variables The number of columns must be equal to the number of values of the variable that has the maximum number of values The name of this array must be VAL_ lt array gt When the procedure is evaluated a random value is computed for each variable according to the frequency table given in lt array gt and these values are stored in an array of name RAND lt array gt to be used in the program The values are computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed Example 1 Test RAND procedure for multivariate random values This example generates random numbers from a distribution given by a three variable frequency table given by an array Mul of three indexes The multivariant frequency table is 15 18 15 18 2 0 l 1 3 2 0 I 3 2 0 1 5 0 4 3 0 4 5 0 1 2 1 10 0 1 3 1 10 0 3 6 So Mul 0 1 5 0 15 4 is the number of cases in which the values of the variables were 0 1 5 0 15 104 CHAPTER 8 FUNCTIONS Mul 0 4 10 0 18 6 he sum of all values is 32 The first matrix sum up 15 the second one 17 he RAND algorithm selects one vector for example 0 1 5 0 15 with a probability according to the frequency table Each value is selected according to its marginal probability distribution conditional to the previ
179. rstProc messages pass to SecProc to be processed one by one The queue in SecProc is limited to 5 When it contains 5 messages the SecProc in FirstProc is stopped See that the node Inc can block itself after it has sent the message to FirstProc checking the following queue The node FirstProc also can block itselfafter sending the message to SecProc Each node can deblock the former when it scan its EL to extract if possible one message 7 7 ENDSIMUL ends the simulation at the end of the actual event Syntax ENDSIMUL It is used to stop the simulation run When it is executed the actual event execution is completed and the simulation run is terminated This procedure can be used in nodes of any type Examples Pop Pop 1 IF Pop 5041 THEN ENDSIMUL WRITELN Polis population is Pop PAUSE When this code is executed the written message is displayed and the operation pauses until a key is pressed If when the code is executed the value of Pop is 5040 after this pause the simulation run finishes Result A WRITELN Maximum Obtained MaxProfit 8 2 WRITELN Press C to continue any other to finish gt Ch READKEY IF Ch c OR Ch C THEN BEGIN ACT StartSearch 0 ACT Result 14400 END ELSE ENDSIMUL When the node Result is activated the value of MaxProfit is displayed The message Press C to continue any other to finish appears and the computer stops waiting for the press
180. ruction gt is executed The lt associated instruction gt must have a SENDTO instruction to send the generated message to a list In the lt associated instruction gt values may be given to the fields of the created instruction by means of the names of the lt field gt variables not the 0_ lt fields gt This must be done before the message is sent to the EL of a node This instruction can be used in nodes of G L D E R A C or general type Examples 1 Death E Heaven N N 1 CREATE Soul BEGIN Nc N SENDTO Heaven END 60 CHAPTER 6 INSTRUCTIONS DECL VAR N INTEGER MESSAGES Soul Nc INTEGER For each message that reach the node Death and it is destroyed a new message with the structure defined in the MESSAGE declaration Soul is created and sent to Heaven The number of creation is counted in the global variable N and stored in the field Nc of the message As the destroyed and generated messages may have different structures the process may be useful to simulate the change of the structure of a message Prod_Order I IT EXPO Tb_Orders Recep_Time TIME Control R File_Order Ship_Order RELEASE BEGIN SENDTO Ship_Order CREATE Prod_Order BEGIN Control_Time TIME SENDTO File_Order EN END STAY Insp_Time 1 UNIF 0 1 0 1 INIT ACT Prod_Order 0 TSIM 100 Tb_Orders 4 Insp_Time 2 DECL VAR Insp_Time Tb_Orders REAL MESSAGES Prod_Order Quantity INTEGER Name STR
181. s of any type Example 7 11 LIFO PUTS THE MESSAGE AT THE BEGINNING OF THE IL OF A L TYPE NODE 89 Crane R Return ProcLoad Command RELEASE IF HeapSize gt O THEN BEGIN NOTFREE SENDTO Return ProcLoad END ELSE SENDTO Command ProcLoad IF F_Crane gt 1 THEN BEGIN STAY GAMMA MTCrane DevTCrane LoadCrane MINI HeapSize UNIFI 2 3 HeapSize HeapSize LoadCrane END Return R Crane RELEASE BEGIN FREE Crane SENDTO FIRST Crane END STAY ReturnTime TRIA 1 2 4 A crane have to remove a heap of packages that may be transported in groups that have at random with the same probability 2 or 3 packages The time to handle and transport the load is taken from a GAMMA distribution When the heap is reduced to zero the process finishes and the crane is available to transport another heap when that is commanded If the remaining heap is not zero the crane have to return to continue the removal The crane is not available during this period Continuation of the process has priority over any other new process of heap transportation Crane operation is simulated by a node Crane of capacity 1 It is activated by a message that represents the order to operate This messages can queue in the EL of Crane The message has a field HeapSize with the size of the heap to be removed and a field LoadCrane to keep the transported quantity When the message is processed the LoadCrane is computed all the heap or 2 or 3 and the
182. s value is not equal to zero the time of execution of the event will be TIME REMA See PREEMPTION instruction 6 17 See examples 1 2 3 4 5 6 7 8 with PREEMPTION and REMA 9 11 12 13 17 18 GLIDER examples book 6 26 SYNCHRONIZE retains messages in the EL to release them together Syntax SYNCHRONIZE lt integer value gt ALL lt logic expression gt EQUFIELD lt field gt lt associated instruction gt SYNCHRONIZE is used to retain messages that come to a node maybe at different times and to release together a set of them at the same time synchronized when certain conditions are met The associated instruction must contain a SENDTO instruction to send the synchronized set The instruction is suited to simulate synchronization processes in assembling lines and gathering items for batch processing The instruction must be used in a node with an EL that has the ability to send messages nodes of G L D and general type with EL When this instruction is executed the EL is scanned from the beginning Each message comparing mes sage is compared with those compared messages that follow it The first comparing message is the firs one in the EL The values of the fields of the comparing message are in the field variables Those o the compared message are put in the 0_ lt variables gt The comparison consists in the evaluation of the lt logic expression that may include field variables of the comparing
183. see example in 2 8 9 7 VARIABLES THAT MAY BE INITIALIZED BY THE USER 109 9 7 Variables that may be initialized by the user IT real its value is the Interval Time until the next activation of the node being executed NT real its value is the Next Time of activation of the node being executed e STAY real its value is the scheduled permanence of the message being processed in the IL of a node type R e TIME real its value is the actual simulation time TITLE string of 80 characters It contains the title of the experiment e TSIM real its value is the total simulation time 9 8 Classes of declarations CONST DBTABLES FACTORS GFUNCTIONS MESSAGES NODES PROCEDURES RESPONSES STATISTICS TABLES TYPE VAR The use of RESPONSES and FACTORS for the design of experiments will be introduced in a future version of this manual 9 9 GLIDER or Pascal predefined types ARRAY BOOLEAN BYTE CHAR CONT DOUBLE FILE FUNCTION FREQ INTEGER LONGINT POINTER PROCEDURE REAL RECORD RET SET STR80 STRING TEXT WORD 9 10 Pascal separators BEGIN CASE DO DOWNTO ELSE END END FOR GOTO IF IN NIL OF REPEAT THEN TO UNTIL WHILE 9 11 GLIDER types of functions GFUNCTIONS DISC FREQ POLYG SPLINE STAIR 9 12 GLIDER separators NETWORK INIT DECL END MODULE EXPER ENDEXP MODULE is used in the NETWORK section to divide the simulation program in units This is very convenient in case of very la 110 CHAPTER 9 RESERVED WORDS 9 13 Ope
184. signation is used For multiple nodes an ASSI instruction see 6 2 may be used The initialization updates the following system variables e M_ lt node name gt that contains the maximum capacity e U_ lt node name gt that contains the actual used capacity It is initialized to 0 e F_ lt node name gt that contains the actual free capacity It is initialized to M lt node name gt The assignation must be also made in any node However if a new capacity are assigned to a R node less than the actual value of U_ lt node name gt the system does not made any warning Updating of F_ lt node name gt or U_ lt node name gt is not automatically made The user must change these values see example below The IL of the node is not altered Examples Storage 1E9 Ocean MAXREAL Pier 5 4 ASSI ParkingLot 1 4 75 34 34 88 If at some point in the execution the values are M_ParkingLot 4 88 U_ParkingLot 4 70 F_ParkingLot 4 18 and it is needed to change the capacity to 100 the following instructions must be put M_ParkingLot 4 100 F_ParkingLot 4 M_ParkingLot 4 U_ParkingLot 4 must be 30 If the needed change of M_ParkingLot 4 is to 50 it results F_ParkingLot 4 20 The value of U_ParkingLot 4 remains 70 The system does not delete the excess messages in the IL When enough resource is freed during the run the used and free quantities will recover the normal new maximum 50 and minimum
185. ssage reaches OrdQueue a scan process of the EL of Line starts If a message in the EL is found with priority less than the incoming message then this is put before of that in the EL So the EL is always ordered in decreasing order of priority In this system the entities that arrive when the gate is open are allowed to pass when they have to wait they are sorted according to their priority This type of sorting may be more easily done using a type L node See examples 2 6 7 8 10 11 12 13 18 GLIDER examples book 6 24 STATE controls activations and state of G type node Syntax STATE lt associated instruction gt It is used to change the state in a type G node The state is specified by the user using variables of any type and giving them values by means of any code It may be used only in type G nodes If it is used must be the first instruction in the code The lt associated instruction gt is only executed if the event refers to the node No execution is made during the scanning of the network The instruction is executed even if the EL of the node is empty If the node is a multiple one the instruction is activated and the value of the index IEV of the event element is passed to the variable INO Thus the programmer can control the execution for the different nodes The lt associated instruction gt cannot have SENDTO instructions but can use Pascal and common GLIDER instructions Examples 6 25 STAY SCHEDULES
186. t include the index between If the node is of D type and has many predecessors and for that reason it has many EL the name of the node must include the name of the predecessor node Example EL_Machine IL_Carrier 2 EL Take Queue3 are examples of list names 53 54 CHAPTER 6 INSTRUCTIONS The first one is the entry list of the node Machine The second one is the internal list of the node Carrier EL_Take Queue3 is the EL of the node Take that has many ELs It indicates the name of the EL for the messages that come from the node Queue3 lt list gt in the syntactical description represents the name of an IL internal list or EL entry list of messages of a node lt associated instruction gt isa lt Pascal instruction gt simple or structured that is included as part of a GLIDER instruction The associated instruction may include GLIDER functions and procedures and the GLIDER instructions that are allowed in each case It may also be a unique GLIDER instruc tion or a list of GLIDER instructions and procedures between the separators BEGIN END Example SCAN EL_Machine BEGIN j UNIF 1 4 IF a lt 5 THEN SENDTO Carrier j END SCAN is a GLIDER instruction see 6 21 used to scan a list of messages in this case the EL of the node Machine The associated instruction between BEGIN END is executed for each scanned message The variable j of the message is set to the value given by the random GLIDER function UNIF
187. t to the EL of the first node that has the EL empty If all the ELs have messages the message is not sent This option only may be used in the code of a type G node Not sent messages remain in the EL of the node Examples 1 Mail D SENDTO Director Secretary File Copies of the message received at Mail are sent to the nodes Director Secretary and File 2 Discrim G Queue IF Class Friend THEN SENDTO FIRST Queue ELSE SENDTO LAST Queue 3 Parkman G ParkinglotLINO SENDTO Parkinglot MIN Parkinglot R Street STAY GAMMA Tpark DevTpark 78 CHAPTER 6 INSTRUCTIONS 4 Ti 22 IT 1 Pr UNIFI 1 4 OrdQueue G LINE IF LineGate Closed THEN BEGIN SCAN EL_Line Poin IF Pr gt O_Pr HEN STOPSCAN F Poin lt gt NIL THEN SENDTO Poin B Line LSE SENDTO LAST Line ND LSE SENDTO Line m m Line G STATE BEGIN F LineGate Closed THEN LineGate Open ELSE LineGate Closed 8 END F LineGate Open THEN SENDTO Process INIT TSIM 100 ACT Ii 0 LineGate Open ACT Line 8 DECL TYPE Opel Closed Open VAR LineGate Opcl Poin POINTER MESSAGES Ii Pr INTEGER END Messages with priorities from 1 to 4 in the field Pr arrive at OrdQueue and they are passed to Line if the variable LineGate has the value Open In this case they continue to Process LineGate is Open and Closed each 8 time units If LineGate is closed then when a me
188. that arrive at Hospital have a Disease type and a Status of seriousness The Critical are put at the beginning of the queue for Diagnostic In Diagnostic a Critical can remove a non Critical from attention The removed is sent at the beginning of the queue Its future time of attention is the remaining time increased 20 After the Diagnostic the messages are sent to one node of the multiple node Treatment according to their Disease Note the declaration and initialization of the field REMA One defect of the program if one Critical is in the IL and two other Critical arrive then they will be put in the queue EL in reverse order See instruction SCAN 6 21 for a solution Note that it is also unrealistic that the variables Status and Disease were uncorrelated See RAND function 8 25 for a solution NETWORK Patient I IT EXPO 5 5 Disease Fdisease Status Fstatus REMA 0 Hospital G IF Status Critical THEN SENDTO FIRST Diagnostic ELSE SENDTO Diagnostic 72 CHAPTER 6 INSTRUCTIONS Diagnostic R Diagnostic Treatment LINO RELEASE BEGIN Disn Ord Disease SENDTO Treatment Dis END PREEMPTION Status Critical AND 0_Status lt Critical REMA BEGIN REMA REMA 1 2 SENDTO FIRST Diagnostic END STAY GAMMA MDiag DDiag INIT Fdisease Hurt 15 Infectous 20 Shock 25 Hearth 30 Internal 20 Fstatus Non_Serious 30 Medium 40 Serious 30 Critical 20 DECL TYPE St Non_Se
189. the USE field of the message to the free capacity variable F_ lt node gt and adding the value of USE to the used capacity variable U_ lt node gt The scan of the EL continues to look for other candidates to use the resource If there is not STAY instruction and one message enters the IL no departing event is generated The message will remain in the IL until it is extracted by an instruction REL see 6 18 that refers to the IL of the node It extracts the first message without assigned exit time it updates the quantity of free and used resource 40 CHAPTER 4 SYSTEM PREDEFINED NODES and it sends the message to the desired node It is important to remark that the EL is examined and the user s code executed even if there is not resource available If the user wants to avoid repetition of all the code or part of it she or he must program the conditions for that omission Example IF F_Parking gt O THEN STAY LOGNORMAL TPark DTPark avoids to compute the STAY if there is no room in Parking 5 If there is the instruction PREEMPTION see 6 17 some of the above operations are modified 6 If the capacity of the node was defined as MAXREAL it is assumed to be infinite and no update is made in the free or used capacity 4 4 4 Relation with other nodes A R type node must have predecessors and successors If the predecessor is a L type node the EL is the same IL of the L node Both nodes must have the same multiplic
190. the event that activates the node where the instruction appears and only in the first activation of the node When the node with this instruction is activated as the first in the execution of an event the lt associated instruction gt is executed Execution is skipped in the activations produced by scanning of the network In a multiple node the effect occurs for all the nodes See instruction DOEVENT 6 7 This instruction can be used in any type of node Examples 1 Road_Entr 1 IT EXPO 1 5 Traffic_Contr G DONODE BEGIN SENDTO Road IT 20 END Messages cars leaving the node Road_Entr are stopped at Traffic_Control Each 20 time units the accumulated messages are sent to Road It is assumed that the messages are not recycled to Traffic_Contr in the event that activates that node 2 Road_Entr 1 22 IT EXPO 1 5 Traffic_Contr G STATE BEGIN N 0 IT 20 END DONODE IFN lt 3 THEN BEGIN N N 1 SENDTO Road END ELSE STOPSCAN 6 9 EXTR EXTRACTS A MESSAGE FROM A LIST 63 Messages cars leaving the node Road_Entr are stopped at Traffic_Control Each 20 time units the node is activated and the instruction associated to STATE is executed This instruction puts N to O and schedules a new activation 20 units of time later It is executed only one time regardless the messages in the EL The DONODE is then executed for the messages accumulated in the EL of Traffic_Control The associated instruction sends
191. the systems for the actual value of the time and then the control goes back to the callingcode So an updated value of the computed variables can be used by the calling code The C type node continues solving the system at the originally prescribed intervals 4 7 4 Relation with other nodes The node has not predecessors but it can have successors to which messages may be sent As was explained above the node can be called from any node for an instantaneous evaluation of the continuous variables 4 7 5 Indexes Type C nodes cannot have index 4 7 6 Continuous Variables Declaration The variables that appear as derivatives must be declared of CONT type All the CONT and RET type variables must be declared together Example 44 C1 C5 CONT Rr REAL H1 H2 CONT ExitPro RET 3 is incorrect A correct declaration is C1 C5 CONT ExitPro RET 3 H1 H2 CONT ExitPro RET 3 Rr or may be cS H2 C1 H1 CONT ExitPro RET 3 Rr REAL note that the order within the list is irrelevant 4 7 7 Examples 1 Tank Source for TankCar A tank receives a flow of water given by a function FEntry and has an outflow proportional to the Level of the tank T CHAPTER 4 SYSTEM PREDEFINED NODES REAL IME is is expressed in the differential equation for the Level When the Level exceeds 3m the SendTankCar subsystem is activated sending is inhibited until the TankCar completes its work SendTankCar subsystem sends t
192. tion is executed the ELs of the node are examined in the order in which they appear in the list If the predecessor is a multiple node the successive indexed nodes indicated in the lt range gt are examined A quantity of messages equal to lt integer value gt or less ifthere are not enough in the EL are extracted For each extracted message the fields are passed to the 0_ lt fields gt and the lt associated instruction gt is executed This must have a SENDTO instruction to send the message to any list If the SENDTO is not executed the message remains in its EL The selected maximum can be known and modified for the next selection using the MAXSEL system variable If the predecessor is a multiple node the index of the EL actually examined is indicated in INO MAXSEL and INO may be used in the lt associated instruction gt The instruction only can be used in type D nodes and if and only if there are more than one predecessor or the predecessor is an indexed node Examples 1 Proda I Sel IT Tproa UNIF 0 2 0 4 Prodb I Sel IT Tprob UNIF 0 1 0 5 Prodc I Sel IT Tproc UNIF 0 2 0 6 Sel D Assemb I MINICLL EL_Sel Proda MINI LL EL_Sel Prodb LL EL_Sel Prodc IF gt 2 THEN SELECT Proda Prodb Prodc I SENDTO Assemb Assemb E Messages parts to be assembled are produced at Proda Prodb and Prodc and sent to 3 queues that are the ELs of Sel When the minimum quantity in the queu
193. tivated during the scanning process and uations of first order lt expression gt The system considers a succession of such instructions ities that demand a ne EL is examined and he message is moved resource used for the the message remains ing time of depart is one successor a copy using the RELEASE art of the code that in as an es E Exit Destroys messages The message in the EL is processed The code in the node is executed e message is destroyed The node is activated during the scanning of the network if the EL is It accepts instructions ivated the solving process starts It may be interrupted and continued when the node is deactivated or activated by special instructions During integration step T EL nor IL It is only activated is activations does not y an event that refers to it It is not activated again during the scanning of the network It has neither EL nor IL It can activate itself and other nodes change variables and sen X General Used to general processes programmed by messages the user These no es may be designed by any other letter different of G L I D E R C A The node is activated during scanning processes this is the main difference with the A type It has not EL or IL unless this is explicitly required by the user The management of these lists must be programmed by the user wi instructions and procedures 1 3 Nodes with indexes The nodes
194. uction Each part that deals wit work but only if the EL is not empty event process The scanning of the ne D Decision Selects messages from accor only i ing to the selection rules indica any of the EL has messages and t not empty C Continuous Solves systems of ordinary differential e of the form lt variable gt as a system of differential equations When the node is ac the execution the node schedules its own activation at eac cause scanning of the network C type nodes have neither A Autonomous Executes events at scheduled times The messages in the EL represent en that capacity during a certain period of time The code has two parts O her processes the outgoing messages The for each message it is checked if the demanded quantity is available If it is so of future depart is scheduled in the FEL and the quantity of ecapacity If there is not enough capacity in the EL When the depart event is executed the message with the correspon he successor node If there are more than so control this process of message sending ime the node moves a message the network is scanned The processes the departing message is only activated by a departing event and executed only once the incoming messages in the EL may be activated during redecessor nodes and sends them to successor nodes It EL for each predecessor Some messages are taking from the ELs and sent to the successor no ed in the code It is ac
195. un time for each field The instruction LOAD imports the data from the file table So the instruction LOAD Group Size Income loads the record values of the table Group into the system created arrays Size and Income So Income Horker1 675000 The model program can now use and change the values of these array The instruction DBUPDATE can pass these modified data to the original file or to other file with the same structure When the values are no longer needed in the simulation they can be discarded by an UNLOAD instruction and the memory they used is freed If the table Goods have the following fields and values 2 9 PROCEDURES 27 Fields Goods Production PrizeIndex Records 1 Housing 380000 1 10 2 Food 7850000 1 05 3 Clothing 56000 1 20 7 Health 22400 1 32 8 Education 837000 1 22 Then the system generatesN_Goods 8 NOM_Goods Housing Food etc andthe constants Housing 1 Food 2 etc This table contains some characteristics of certain goods The table ConsPatt will describe the consumption pattern of the population groups indicating how much each group consumes of each good One part of this table may be Fields Group Goods Consumpt Priority Records 1 Entrep1 Housing 150400 8 2 Entrep1 Food 250100 5 3 Entrep1 Clothing 170000 5 7 Entrep1 Health 230000 7 8 Entrep1 Education 296000 8 9 Entrep2 Housing 75000 7 10 Entrep2 Food 92000 6 11 Entrep2 Clothing 80600 5 15 Entrep2 Health 119000 7 16 Ent
196. up to three messages to Road 6 9 EXTR extracts a message from a list Syntax EXTR lt list name gt lt pointer gt lt associate instruction gt It is used to extract a message from a list of messages lt list name gt indicates the list lt pointer gt is a variable declared of POINTER type or may be FIRST or LAST The pointed message or the first or last is extracted the values of its fields are passed to the 0_ lt variables gt and the lt associate instruction gt is executed After this the values in the 0_ lt variables gt are passed to the fields of the messages The lt associate instruction gt must have a SENDTO instruction to send the message to a list This instruction can be used in any type of node and in the associated instruction of a RE LEASE Example Process1 R Process2 ProcFile2 RELEASE BEGIN SENDTO Process2 SCANCIL_ProcFile1 PFile IF NumP1 O_NumP1 THEN STOPSCAN EXTR IL_PartFile PFile SENDTO ProcFile2 END STAY UNIF 32 36 When a message object to be processed leaves the node Process1 is sent to Process2 Then a IL used to simulate a file is scanned until a message is found with the same value in the field NumP1 as the leaving message The found message that is now pointed by the POINTER PFile is extracted and sent to the node ProcFile2 6 10 FILE writes values in a text file Syntax FILE lt file name gt lt list of expression format gt It is used to write a line
197. used it will appear as a title in the graphic It may be omitted TIME lt format gt lt color gt is only used when the independent variable will be the TIME of the simulation lt format gt is a Pascal format to write the values of the TIME along the horizontal axis lt color gt is the color of the horizontal axis and the values on it lt list of variable descriptors gt isa list of items describing the parameters to represent the variables to be depicted 6 11 GRAPH DRAWS GRAPHICS DURING A RUN 65 If TIME lt format gt lt color gt is omitted the variable of the first descriptor is taken as independent variable and its values are on the horizontal axis Variable descriptors are separated by lt list of variable descriptors gt consists of the following elements separated by commas They describe the variables to be graphed e lt real expression gt that expresses the value to be graphed it may be a single variable or constant e lt format gt gives the format for the values on the axis it consists of lt number of places gt lt number of decimals gt e lt name of the graphed values gt a name that will appear in the graph It is a string of characters without blanks apostrophes or commas e lt minimum value gt a real number with the minimum value expected e lt maximum value gt a real number with the maximum value expected e lt color for the curve color must be anyone of the following list
198. ust be in a file with extension GLD in ASCII code It is a text file with lines of 75 characters at most from column 1 to 75 10 3 Operation without environment The source file must be in the directory of the GLIDER system The process of compiling and execution is called with the command gt GL lt filename gt The extension GLD must be omitted The GLIDER compiler produces a Pascal program that is then com piled by the Turbo Pascal compiler TPL EXE The executable program remains in the file lt filename EXE gt Then the execution phase begin That starts with the Initial Menu 10 4 Initial menu This menu appears at the beginning of the execution It has the following options Initialize and run set Title of the experiment make Replications Graphic set Additional time Quit Oraaan e I to initialize the system variables it executes the INIT section and it calls the Run Interactive Menu e T allows to introduce a title up to 80 characters that will appear in the statistical output e R allows to make replications of the run without re initializing the seeds of the random numbers e G to display a graphic for the results filed with the FILE instruction during a simulation run e A to run an experiment with extra time after a run e Q to abandon the run After this menu the INIT section is executed and the Run Interactive Menu is called 10 5 Run interactive menu It appears after the execution of the INIT section
199. value of a random variable whose probability function is a triangularfunction with minimum equal to the first lt real expression gt mode equal to the second lt real expression gt and maximum equal to the third lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 27 UNIF random value from a real Uniform distribution Syntax 106 CHAPTER 8 FUNCTIONS UNIF lt real expression gt lt real expression gt lt stream gt Returns a REAL value of a random variable whose probability function is a continuous uniform function with minimum equal to the first lt real expression gt and maximum equal to the second lt real expression gt computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 28 UNIFI random value from an integer Uniform distribution Syntax UNIFI lt real expression gt lt real expression gt lt stream gt Returns an INTEGER value of a random variable whose probability function is a discrete uniform function with minimum equal to the first lt real expression gt and maximum equal to the second lt real expression computed with random numbers taken from the stream indicated by lt stream gt This is an integer from 1 to 10 If omitted 1 is assumed 8 29 WEIBULL random value from a Weibull distribution Syntax
200. within lt gt Example lt variable gt means the name of a variable e elements that can be omitted are within e ifan element of the language is between it means that there are other alternatives for the element The other alternatives are also between and only one of them must be used Example LAST FIRST in a syntactical description means that one of the two the word LAST or the word FIRST must appear e lt integer value gt is an integer variable taking only positive values or a positive integer Examples 3 334 J J was defined as INTEGER LONGINT WORD or BYTE and must have a positive value e lt node gt means the name of a node If the node is multiple the name must include the index within Examples Machine Carrier 3 Take are examples of node names They must have been declared as nodes in the program see chapters 4 and 5 The node Carrier must have been declared as a multiple node e lt list of lt elements gt gt means a list of the items indicated by elements separated by commas Examples lt list of lt integer values gt gt may be a list as J 3 350 h lt list of lt nodes gt gt may be Machine Carrier j Inspect where Machine Carrier and Inspect were defined as nodes elsewhere Carrier was defined as a multiple node e the lists of messages are denoted in the program by EL IL _ lt node gt lt name of predecessor node gt The node name of a multiple node mus
201. work If it has an index only the node with the index of the event is activated 4 1 3 Function When activated 1 If there is an IT instruction a next activation of the node is scheduled to happen at the time TIME IT 2 A message is generated that always contains the default fields 33 34 CHAPTER 4 SYSTEM PREDEFINED NODES e GT Generation Time contains the value of TIME at the generation e USE quantity of resource to be used in node R Initialized to 1 as default value ET to put the time of entrance in a list EL or IL XT to put the time of future exit from a list EL or IL NUMBER number of the message generated in the node e NODE name of the node The user can change the USE by a USE instruction NUMBER NODE and GT remain constant ET are changed by the GLIDER system each time the message enters a list XT is updated each time the message enters a IL and a departure time from it is scheduled 3 The user s instructions are processed These may usually be assignation of values to the message fields and SENDTO instructions to the message to other nodes one and only one SENDTO is to be executed Assignation of values to the fields are made by assigning values to the corresponding field variables If here is not a SENDTO instruction in the code the message is automatically sent to the successor node If there are more than one successor a copy is sent to each successor 4 Before the sending of th
202. xample Physician R RELEASE BEGIN Revised TRUE SENDTO Treatment Disease END STAY TRIA 4 6 9 Messages patients that leave the node Physician after completing its scheduled time of attention given at the entrance by the instruction STAY are tagged putting TRUE its field Revised Then they are sent to one node of the multiple node Treatment according the value of their field Disease See examples 9 and 13 GLIDER examples book 74 CHAPTER 6 INSTRUCTIONS 6 20 REPORT allows to write an output report in files Syntax REPORT lt code gt ENDREPORT This instruction is used to show and file user s built reports of partial or final results of a simulation run All the instructions between the delimiters REPORT and ENDREPORT are executed Pascal instructions WRITE WRITELN etc and common GLIDER instructions in particular OUTG can be included Before writing the GLIDER system asks for the name of the file to write in CON is used to write in the screen LPT1 to the line printer Instructions that write some output will do that in the files indicated by the user just before the writing After finishing the system asks if another writing is required The same writing may be repeated in different files for instance first in the screen and after in a disk or printer If it is desired that some included writing instructions use other file than that indicated for the whole report the file variable OUTF must be used in those i
203. y blocked nothing is done When the event state is changed again to active state see DEBLOCK 7 6 the delayed events are executed at the actual time This procedure can be used in nodes of any type Example Arrivals I IT Farr TIME IF LL EL_Entrance gt 8 THEN BLOCK Arrivals Entrance RELEASE BEGIN SENDTO Parking LL EL_Reception lt 5 THEN DEBLOCK Arrivals END STAY TicketTime Messages cars are generated at irregular times given by the function Farr TIME When a queue of 9 is formed at the parking Entrance the generation is stopped the scheduled next arrival is suspended until the queue is less than 5 See DEBLOCK procedure 7 6 for another example 7 4 CLRSTAT re starts the gathering of statistics Syntax CLRSTAT It is used to reset to zero the variables in which the statistics are accumulated Thus the statistics are counted since the last time in which a procedure of this type is executed That time is recorded in the standard statistics This procedure can be used in nodes of any type Examples PassTrans A IT 1000 IF ABS Qma MEDL EL_Tell 0 5 Qma MEDL EL_Tell lt 0 03 THEN BEGIN Stable TRUE CLRSTAT BLOCK PassTrans END ELSE BEGIN Qma MEDL EL_Te11 CLRSTAT END INIT TSIM 24000 ACT PassTrans 200 Qma 0 Stable FALSE 86 CHAPTER 7 PROCEDURES At intervals of 1000 time units the queue EL_Tell is examined The previous mean length Qma is c
204. y default Basic Experiment The user can put other titles by program see instruction TITLE 6 27 or from the Menu The total simulation time and the last time in which the Statistics were cleared see procedure CLRSTAT 7 4 are also shown If replications of the experiment are asked for the number of the replication is given The date and time of the beginning of the execution and the computing time spent in the simulation are also recorded For the I type nodes the number of generated messages is shown For each EL and IL the number of entries the actual length and the maximum length are displayed The statistics show the mean length and its deviation the maximum and mean waiting time of the messages in the list its deviation and the time that the list remained empty For the E type nodes the mean time in the system of the messages destroyed at the node and its deviation are recorded In this example only the used time of the resources are displayed because no other variables in the STATIS TICS were requested The statistics given are the mean and deviation of the variables as a function of time the maximum and minimum values the mean and deviation of the values and the actual final value 1 5 Example 2 Port with Three Types of Piers This is the simulation of a port that has three types of piers to receive different types of ships 1 ships with general charge 2 ships that bring charge to be discharged in bulk to sil

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