Goal User Manual
Contents
1. v MAS Projects v stackBuilder goal Other files Re opening MAS projects Re opening other files Figure 4 8 IDE after loading the blocksworld mas2g file Figure 4 7 shows the result of double clicking on the stackBuilder goal agent file 4 2 2 Saving an Agent File As discussed above an agent file can be saved when the editor with the code of the file is open Simply press the Save button or use ctrl s or apply s to save the file Upon saving a goal file the file is also parsed If any syntax errors are found in the file these will be shown including references to line numbers in the parse info tab in the feedback area 4 2 3 Changing a File Name To save a copy of the file with a different name select File Save As A file dialogue window will appear in which you can select a different file name and location GOAL automatically switches the editor to the latest saved file The files panel is updated accordingly A warning is in place however Changing a file name that is part of a mas project by means of the File menu does not modify the contents of the mas file itself When changing an agent file name you need to manually change the agentfiles section of the mas file A popup will remind you to edit the mas file 22 CHAPTER 4 CREATING AND MANAGING MULTI AGENT PROJECTS 4 2 4 Using the File Menu to Remove a File A file that is a part of a MAS project can be removed from the files pan2. Print messages from parser r repeats number Number of times to repeat running all episodes recursive Recursively search for mas files rmi jhostj Use RMI messaging middleware Host is the location of the RMI server Using localhost will initialize a RMI server timeout jseconds Timeout of the multi agent system v verbose Print all messages version Shows the current version W Print messages from warning 7 4 Runtime Settings Some settings e g used middleware are used as set in the preferences Note that these preferences can be set using the GOAL IDE but also by direct calls Please refer to the JavaDoc for the various preference settings inside the goal preferences directory There are preference settings for the CorePreferences PMPreferences the Logging Preferences etc Also notice the w and v options of the tool if you are looking for warning printouts 7 5 Interaction with Standalone In some cases user interaction is still required in a stand alone run Usually this is because the environment needs additional setup actions before it can really be used Termination does not always imply reset of the environment You may have to set init param eters in the MAS to request reset of the environment for the next run 7 6 Batch Running The Run command above allows you various variants for batch running You can specify a directory containing multiple prepared MAS files and or you can request
3. e X indicates that the process has been killed Note It may happen that an agent tries to perform an action in an environment when the environment has been paused because the agent process and environment run asynchronously In that case the environment may throw an exception which will be printed as a warning in the console tab The agent will proceed as if the action has been succesfully executed Finally note that environments can be in running and paused mode but not in stepping mode 5 5 Resetting a MAS and Its Environment You can use reset to reset agents and environment If you select a MAS process node and apply reset only the agents are reset but not the environment To reset the environment select the environment and apply reset Note that reset of the environment keeps the agents connected and alive so this is less complete than a kill and restart of the entire MAS The Backward stepping button in the tool bar is not yet supported 5 6 Distributed Running of One or More MAS The agents in a multi agent system and the environment to which the agents are connected can be distributed over different machines The middleware infrastructure that is used to run the multi agent system needs to support distributed processing 5 6 1 Messaging Infrastructures The term messaging refers to the communication infrastructure on top of which a multi agent system runs Messaging enables agents to exchange messages between each other GOAL cu
4. GOAL IDE File Edit Run Debug 8 4 Debug Files N stackBuilder goal x gt MAS Projects iit t ijinit module v E blocksworld n SE knowledge stackBuild 3 only blocks can be on top of another object v M mybw mas2g 4 block X on X _ An 5 a block is clear if nothing is on top of it clear X block X not on X le tableAgen 7 the table is always clear 3 Other files clear 0 9 the tover predicate holds for any stack of blocks that sits on the table 10 tower X oniX 0 L 11 tower X Y T on X Y tower Y T 12 13 heliefs 14 v 15 goals 16 on a table on b a on c b on d table on e table on f e on g on h g on i h n 17 on 1 0 on 2 1 on 3 2 on 4 0 on 5 0 on 6 5 on 7 6 on 8 7 on 9 8 18 v 19 actionspec 20 not on X Y in precondition to prevent moving a block on the table to another place on the ti Yv 2n move X Y 22 pre clear X clear on X 2 not on X Y me EE post not oniX Z oniX Y L 24 129538 26 27 2sjmain module exit nogoals 2 program order random 30 define misplaced X a goal tover X T 31 define constructiveMove X Y a goal tower X Y T bel tover Y T 32 33 if constructiveMove X Y then move X Y n 34 if misplaced X then move X 0 TOSS 361 37 3sjevent module
5. See Section 9 1 for more about reporting an issue When an identical problem re occurs a warning message is re printed only a limited number of times to prevent the Console from being flushed with identical messages When the Console shows the message for the last time it will add the message New occurrences of this warning will not be shown any more You can adjust the number of times that a message will be re printed in the Logging tab in the Preferences menu 42 CHAPTER 6 DEBUGGING A MULTI AGENT SYSTEM Chapter 7 Running in Stand Alone Mode You can run a multi agent system containing GOAL agent programs stand alone that is without starting the IDE That way you can use GOAL from scripting languages like a shell script or bat script or from your Java program Stand alone running always involves starting up a Java Virtual Machine JVM with the right environment settings We first describe the required environment and then describe how to use this from a Java program or from a script 7 1 Setting the JVM environment The variables to be set up properly for the environment are the PATH the JAVA_LIBRARY_PATH CLASSPATH and the SWI_HOME_DIR Below we use the tag GOALHOME to point to the absolute directory where you installed GOAL The exact way to do this is machine dependent we assume you have the knowledge how to do this on your particular machine For example the used as separator in the CLASSPATH below should be re
6. Action move b table has no available instantiations stackbuilder Rule if misplaced X then move X table is not applicable after all stackbuilder Rule if constructiveMove X Y then move X Y has 1 potentially applicable instantiation s Y a X b stackbuilder Precondition clear b clear a on b Z not on b a of action move b a holds when instantiated by _Z table stackbuilder Round 20 stackbuilder Received percepts percept on a table percept on b a percept on c table percept on d table percept on e table percept on f e pe stackbuilder Evaluating event module stackbuilder Rule forall bel percept on X Y not on X Y do insert on X Y is not applicable stackbuilder Rule forall bel on X Y not percept on X Y do delete on X Y is not applicable stackbuilder Evaluating main agent program stackbuilder Rule if misplaced X then move X table has 1 potentially applicable instantiation s X c stackbuilder Action move c table has no available instantiations stackbuilder Rule if misplaced X then move X table is not applicable after all stackbuilder Rule if constructiveMove X Y then move X Y has 1 potentially applicable instantiation s Y b X c stackbuilder Precondition clear c clear b on c Z not on c b of action move c b holds when instantiated by _Z table stackbuilder Goal on a table on b a on c b on d table on e tabl
7. Apart from being able to view the contents of an agent s mental state when it is paused an introspector also allows you to pose queries for evaluation on the current mental state of the agent in the Query Area All solutions for the query performed are shown in the query window They are shown in the query result area as a list of substitutions for variables Figure 6 2 shows the results of performing the query bel clear X clear Y on X Z not on X Y This mental atom corresponds to the precondition of the move action in the Blocks World environment and shows all the options to move blocks that are available in the present state Consult the GOAL Programming Guide 3 for a detailed explanation of mental state conditions 6 3 EXECUTING AN ACTION USING THE INTROSPECTOR 31 GOAL IDE File Edit Run Debug Sniffer Process Overview bw2agents mas Blocks World Goals Mails Percepts Knowledge a tableagent Jagent stackbuilder Lo stackbuilder me stackbuilder lagent tableagent jon g h jon e f on c d Z h Y c X g Z h Y b X gl Z h Y table X g Z d 9 X c Z d c X c Z d b X c Z d Y table X c Z a 9 X b 2 Z a Y b X b Z a Y table X b Consolex Parselnfox Action log stackbuilder Database query assert belietbase2 a has the following solutions stackbuilder on b a
8. As for knowl edge files a subnode for the imported module file is created below the agent file There are two types of files that can be imported Files that contain modules and files that contain knowledge The first are called module files and have the extension mod2g whereas the second are called knowledge files The extension of knowledge files depends on the kind of knowledge technology that is used in case Prolog is used these files have the extension 1 Even if an agent is not a very large program it sometimes is useful to put some of the code in separate module or knowledge files to facilitate reuse The code in a knowledge section of an agent for example can be re used in another agent program Reusing the same code by creating a separate file that is used in multiple agent files prevents possible problems introduced by modifying the same code that appears at different places in only one location By using a dedicated file the code is needs to be maintained and modified in only one place 4 2 MANAGING AN EXISTING MULTI AGENT PROJECT 19 eoo GOAL IDE GOAL IDE File Edit Run Debug 21 1 1518 gt w x Dems Files N bwEvent mod2g x v P MAS Projects TIN v 1 mo e vR blocksworkd maszg knowledge stackBuilder goal t 3 import bwEnowledge pl 6 bwKnowledge pl 4 5 beliefs bwEvent mod2g 6 mybw mas2g Y 7 goals v 8 stackBuilde
9. IDE This is due to a known bug in Java for Windows You need to install java 7 or higher to fix this issue Java 7 is available from http download java net jdk7 binaries 47 48 CHAPTER 9 KNOWN ISSUES AND WORKAROUNDS 9 1 Reporting Issues If you discover anything you believe to be an error or have any other issues you run into please report the error or issue to goalQii tudelft nl Your help is appreciated To facilitate a quick resolution and to help us reproduce and locate the problem please include the following information in your error report 1 A short description of the problem 2 All relevant source files of the MAS project 3 Relevant warning or error messages from the Feedback area especially from the Console and or Parse Info tab Please also include Java details and stack trace information if avail able see Section 6 7 2 for adjusting settings to obtain this information 4 If possible a screen shot of the situation you ran into Bibliography Tristan Behrens Environment interface standard project http sourceforge net projects apleis Tristan Behrens Koen V Hindriks and Jrgen Dix Towards an environment interface standard for agent platforms Annals of Mathematics and Artificial Intelligence pages 1 35 2010 10 1007 s10472 010 9215 9 Koen V Hindriks GOAL Programming Guide Delft University of Technology 2014 http ii tudelft nl trac goal wiki WikiStart Documentation Koen V Hindriks
10. The GOAL Agent Programming Language http ii tudelft nl trac goal 2014 49
11. is on by default IMPORTANT with sleep agents selected your agent may go to sleep when it is repeating actions This may be counterintuitive and may cause GOAL programs to malfunction In doubt you should turn off this option To remove agents automatically after they have been killed select the Remove agents when they are killed option To run new agents automatically as their entities appear select Run agents automatically when the environment is already running These two options are useful in environments where large numbers of agents appear and disappear while GOAL is running 6 7 RUNTIME PREFERENCE SETTINGS 41 6 7 2 Warnings Warnings and errors are shown depending on how you set the preferences Warnings generally appear in the Console area see Section 6 4 By default warnings are plain messages For development purposes however the format of warnings can be adjusted using the Logging tab in the Preferences menu Select to Show Java details to include the Java specific part of a warning message In some cases this can help to see what the platform was attempting to do Select Show Java stack traces to add a full stack dump to warning messages This is mainly intended to aid debugging of the platform itself but in some cases may also help you to understand what the platform was trying to do Reporting Issues When reporting an issue it is very useful if your issue report includes Java details and stack traces
12. percepts Mails and percepts are buffered and collected at the start of an agent s reasoning 6 5 SETTING BREAKPOINTS 35 cycle A report containing the percepts and or messages received is provided as output in the Debug Tracer e Evaluation of action rules concerns the evaluation of the mental state condition and appli cability of action rules Depending on the rule evaluation order more or less rules will be evaluated each reasoning cycle The debug output will show all substutions for which the rule is applicable if any e Evaluation of action preconditions relates to the evaluation of the preconditions of actions In case this breakpoint is selected to pause on the agent will halt just before executing the action itself If this breakpoint is viewed reports of the evaluation of all action preconditions are provided e Besides the action log which actions are executed can be provided as debug output in the Debug Tracer as well by checking the View check box related to either the Built in actions or Actions sent to the environment breakpoints e The Changes to the belief base and changes to the goal base breakpoints provide output related to or pause when a change to either base is made The Changes to the belief base breakpoint usually is a too finegrained breakpoint to pause on as many changes to a belief base are made e The Goals that have been achieved breakpoint can be quite useful to verify whether a goal has been achieved an
13. w program 40 the Blocks World is fully observable 41 forall bel percept on X Y not Y do insert on X Y t 42 forall bel on X Y mot percept on X Y do delete oniX Y 43 al H y MT Ic av r Consolex Parselnfox Actionlogx Re opening MAS projects Re opening other files File stackBuilder goal saved 20 67 Figure 4 7 IDE with editor window for the stackBuilder goal file goal module files with extension mod2g and knowledge representation files The extension of the latter type of file depends on the knowledge representation that is used When Prolog is used files with extension pl may be part of a mas project Module and knowledge representation files are referenced in agent files It is also possible to open existing GOAL agent and other files that are not part of any mas project Note that you do not need to load agent files that are part of a mas project as these are added to the files panel automatically You can do so by using the File Open menu and selecting an agent file with extension goal This agent file will be added below the Other Files node in the files panel Any file that is not identified as part of a mas project will be placed below the Other Files node 4 2 1 Editing Files Editing a file can be done in the editor window 4 2 MANAGING AN EXISTING MULTI AGENT PROJECT 21 l oles eix m a p ojajx 4
14. GOAL User Manual Koen V Hindriks and Wouter Pasman March 3 2014 Contents Introduction Installing the GOAL Platform 21 System Kequiremenia 22 442 aa eb Ho we Zu 2o nx 4 an ra oe ihr Za Uninstalling lt oa 43 okgexe EE X x a Eu 24 ca oc ida A Box 25 Installation for Admins 42 222 b om ebb we ea Starting the Integrated Development Environment ad Keyboard cosida uU Ra EY 32 Beadback ABA coz ua vow m AA OX S en a o Customizing the IDE ala xU RR FX P OY Wo Creating and Managing Multi Agent Projects 4 1 Creating a New Multi Agent Project 4 1 1 Adding an Agent File toa 5 41 2 Using the File Menu to Create a New Agent File 4 1 3 Adding an Environment toa MAS Project 114 Adding a Launch Policy 4 1 5 Importing Knowledge and Module Files 4 2 Managing an Existing Multi Agent Project dai Billing PR so oe oe Dee a re Y 122 Saving an Agent Pe xa wwe RR SER a 423 3 Changing Pile Name 002220 Wann Rm REGE on og 4 2 4 Using the File Menu to 4 2 5 Automatic Word Completion oe sa ecce a Gor ae A a Running a Multi Agent Sys
15. Log files are written to the logs directory inside the directory where GOAL was installed You can change it by clicking on the Browse button of the Write log files here field Most logs are in XML format and each log entry contains a timestamp with millisecond accu racy Debug messages for each agent are written to lt agent gt log All actions are written to histo ryOfA ctions log General info is written to goal tools logging InfoLog log Warnings are written to goal tools errorhandling Warning log Sytem bug reports are written to goal tools errorhandling SystemBug log Result of log actions are written to lt agent gt _ lt timestamp gt txt files Be careful with this option as many megabytes per second can be written A new run generates new log files made unique by adding a number to the names By selecting Overwrite old log files a new run uses the same file names thus overwriting previously generated files The type of debug messages that are logged can be determined with the view checkboxes in the global breakpoints preferences panel Figure 6 4 The warnings print format allows you to select the information that is printed along with any warning You can turn on the stack trace and the detailed java message Also you can set the maximum number of times the same message is printed to avoid flooding of the console SOS GOAL Preferences 4 kogging Introspector PlatformManager Database Export Log
16. TOR Close Figure 3 2 The GUI amp Files tab in the Preferences Menu The default options are depicted in Figure 3 2 the options include e Changing the default Java look and feel to the Nimbus look and feel e Re opening of files at start up Remembering window sizes and position of main IDE window Setting the font size for the Console area in the Feedback area Setting the maximum number of lines in the Console area and in the Introspector 12 CHAPTER 3 STARTING THE INTEGRATED DEVELOPMENT ENVIRONMENT Chapter 4 Creating and Managing Multi Agent Projects The Integrated Development Environment IDE distributed with GOAL facilitates creating new and managing existing multi agent projects This chapter explains how to use the IDE to do this 4 1 Creating a New Multi A gent Project Save As Hello World Example me Date Modified L HelloWorld mas2g Thursday January 23 2014 HelloWorldAgent goal Thursday January 23 2014 ScriptAgent goal Thursday January 23 2014 ScriptAgent mas2g Thursday January 23 2014 Figure 4 1 The New MAS File Dialogue Window 13 14 CHAPTER 4 CREATING AND MANAGING MULTLAGENT PROJECTS MAS files are files with extension mas2g Note that you need to provide the extension yourself in case a window in the top level bar requests you to Provide a name for a new GOAL Agent the system will properly handle the MAS extension in that case You can make sure that you are a
17. and the Open Introspector item in the Debug menu Introspectors are located in the content area of the debug mode Figure 6 1 shows an intro spector for the stackbuilder agent that is part of the bw2agents mas2g project An agent introspector consists of various tabs that allow you to access the current contents of the agent s beliefs goals mails percepts and knowledge In the area showing the contents you can select text and copy it to somewhere else 29 30 CHAPTER 6 DEBUGGING A MULTI AGENT SYSTEM jaja ajo vw jeixiuwja po a Qjx 5 B 4 Process Overview bw2agents mas Blocks World tableagent agent stackbuilder me stackbuilder agent tableagent on e f on c d on f table Consolex Parselnfo Action log Istackbuilder Database query assert belietbase2 a has the following solutions 1 stackbuilder on b a has been added to the belief base and on b c has been deleted stackbuilder Database query true beliefbase2 on a table onib a on c b on d table on e table onif e stackbuilder Executed move b a stackbuilder Database query true beliefbase2 on a table onib a on c b onid table on e table ontf e stackbuilder Round 1 Figure 6 1 An Introspector for the stackbuilder agent 6 2 Querying a Mental State
18. and therefore you may have to remove part of the goals 4 open SWI Prolog see the SWI Prolog manual and import the Prolog file e g consult lt filename gt 5 start the SWI Prolog tracer e g type trace in its console 6 run and trace the query see SWI Prolog manual typically the n a and enter are used for tracing If you selected opening of files while exporting the mental state contents these files are opened in edit mode Switch back to edit mode in order to view the contents Figure 6 8 shows the results for the stackbuilder agent 6 6 2 Prolog Exceptions When an exception occurs in the Prolog engine SWI Prolog error messages may get a bit hard to decypher This section explains how to read such messages A typical PrologException will show up typically like this WARNING jpl PrologException PrologException error instantiation error context system gt 2 _1425 query true beliefbase6 openRequestOnRoute L D T The first of the two lines indicates the message that Prolog gave us The second line shows the query that caused the warning To read the first line notice the part error CAUSE DETAILS inside it The CAUSE part gives the reason for the failure the DETAILS gives the context of the error Several types of CAUSE can occur amongst others 6 7 RUNTIME PREFERENCE SETTINGS l GOAL IDE File Edit Run Debug Sniffer Help Wem exe iles 9 P MAS Proj
19. atform is installed The files associated with a MAS project are displayed in the File panel on the left hand side of the main IDE window Figure 4 8 shows the IDE after loading the blocksworld mas2g file Multiple MAS projects can be present at the same time in the files panel A MAS file specifies the agent files that are needed to create the agents of the multi agent systems These agent files are listed in the agentfiles section of the mas file The files present in this section are listed as subnodes of the mas file in the files panel and are automatically loaded when the mas file is loaded Note that the parse info tab indicates when the mas file was loaded and whether it has been parsed successfully The only agent file present in the blocksworld mas2g file is the stackBuilder goal as shown in Figure 4 8 The contents of a mas file can be viewed and edited by loading it into the built in editor of the IDE You can do this by double clicking on the mas file in the files panel Alternatively you can select the mas file in the files panel and selecting File Edit in the IDE menu Similarly the contents of an agent file can be viewed and edited The GOAL Programming Guide 3 contains a detailed explanation of the contents of a mas file A mas project consists of a main mas file with extension mas2g agent files with extension 20 CHAPTER 4 CREATING AND MANAGING MULTI AGENT PROJECTS 000 GOAL IDE
20. ch help Note that these messages commonly contain pure functional notation where you might be more used to the infix notation For instance system X appears as system X and gt 2 appears as gt 2 3 representation error the form of the predicate was not appropriate for instance a bound variable was found while an unbound variable was expected 4 permission error you have insufficient permissions to execute the predicate Typically this occurs if you try to redefine system predicates 5 resource error there are not enough resources of the given type 6 7 Runtime Preference Settings Most settings are selected via a number of preference panels Figure 6 9 This section discusses them The preferences panel is accessed via Help Preferences Windows Linux or via GOAL IDE Preferences MacOSX 40 CHAPTER 6 DEBUGGING A MULTLAGENT SYSTEM 800 GOAL Preferences 4 PlatformManager Database Export Environment gt Q Always run the middleware locally Start browsing for agent files here Volumes documents EclipseWorkspaces GOAL GOALa Browse V Remember last used agent directory default KR Language swiprolog E High Performance options C Sleep agents when they repeat same action _ Remove agents when they are killed Dynamic Environment options C Run agents automatically when the environment is already running Close Ne Figure 6 9 Prefere
21. d Click blocks to stack Spacebar to reset initializing mental state connecting to entity gripper OK m y 4 Figure 5 1 The IDE after launching bw2agents mas2g 5 1 Launching a Multi Agent System Launching a MAS means e Launching an environment referenced in the MAS file if any and e Creating agents in line with the launch policy of the MAS 23 24 CHAPTER 5 RUNNING MULTI AGENT SYSTEM How to launch a MAS file e Select a MAS file in the Files panel e Press the Run button in the tool bar Alternatively select Run in the Run menu The IDE will automatically switch to the debug perspective when a MAS is launched In this perspective instead of the Files panel the Process panel is shown in the main content area as illustrated in Figure 5 1 The Process panel shows the processes that have been created by launching the MAS In the Blocks World example an environment process is started labelled Blocks World as well as two agent processes named stackbuilder and tableagent Also the Blocks World GUI shown in Figure 5 2 should appear All processes that are created are paused initially which is indicated by the icon just left of the process names 800 wg Figure 5 2 The Blocks World GUI after launching bw2agents mas2g Before launching a MAS make sure to check that the MAS project is clean That is check the Parse info tab in the Feedback area and make sure no warnings
22. d to halt an agent whenever this happens e The last two breakpoints are the most finegrained level breakpoints available and typically are not very useful They provide detailed output on basic queries at the level of mental atoms and or queries performed using the knowledge representation language e g Prolog You can modify the selections at any time also during the execution of a mas If you are stepping a multi agent system agents will continue to run until they hit the next breakpoint selected to pause on If such a breakpoint is hit the agent is switched to pause mode Note that the Step button has the same effect as the Run button if no breakpoints have been selected In that case the agent progress will be run without halting the agent with the exception of explicitly set breakpoints which we discuss next As an example clear all Pause check boxes in the Breakpoints panel and only select to pause on the Goals that have been achieved breakpoint Launch the bw2agents mas2g mas and press the Step button several times to get things started The agents run until the stackbuilder agent achieves its goal which demonstrates the agent is able to achieve it even in the presence of the tableagent agent Figure 6 5 shows an example run where this happens in round 20 6 5 2 Setting Code Line Breakpoints A second more flexible way of setting breakpoints is by adding code line breakpoints In GOAL breakpoints can be associated with four con
23. dded to the elevator GOAL IDE mme ee Oi Sex File Edit Run Debug Sniffer Help Aate op Iex ni rocess Overview bw2agents mas2g E Blocks World i tableagent Er Executed se 0 stackbuilder Executed insert on f table stackbuilder Executed insert on h i istackbuilder Executed insert on i table stackbuilder Rule forall bel on X Y not percept on X Y do delete on X Y is not applicable stackbuilder Evaluating main agent program stackbuilder Rule if misplaced X then move X table has 9 potentially applicable instantiation s X a X d X e X c X f X g X h X i stackbuilder Precondition clear h clear table on h Z not on h table of action move h table holds when instantiated by Z i Figure 6 7 The stackbuilder agent paused on an explicit breakpoint 6 6 Prolog Level Debugging The GOAL IDE does not support tracing of Prolog queries inside the Prolog inference engine If you need this level of detail while you are debugging an agent it is useful to be able to export 38 CHAPTER 6 DEBUGGING A MULTLAGENT SYSTEM the contents of a mental state to a separate file that can be imported into Prolog Then use the Prolog tracer to analyze the code 6 6 1 Exporting a Mental State to a File To export the mental state o
24. e on f e on g f on h g on i h has been achieved and is removed LT K ji gt Figure 6 5 Pausing on Goal Achieved Breakpoint An example of two breakpoints that were added to the move action specification is illustrated in Figure 6 6 Different from the built in breakpoints even if a multi agent system is put in run mode the system will halt on any explicit breakpoints that have been set Figure 6 7 shows that the stackbuilder is paused when the breakpoint set on the action specification is hit Breakpoints that are associated with action specifications and action rules provide useful output in the Debug Tracer immediately This is not the case however for breakpoints set on modules The output produced in this case only provides a clue that the module is about to be evaluated Take it from here to step further through the module using the Step button to produce more relevant debug output Explicit breakpoints that have been added to a file are not saved Upon closing an editor all breakpoints set are lost This is an easy way to clear all breakpoints 6 5 3 Switching Between Edit and Debug Mode The GOAL IDE has two modes Edit mode and debug mode see Figure 3 1 and Figure 5 2 respectively As explained in edit mode a files panel is shown that displays the structure of a mas project whereas in debug mode a process panel is shown that displays the processes that are
25. e IDE by any of the following methods Double click on the GOAL icon on your desktop Select GOAL from the program menu Run the goal exe file Windows goal app file OSX or the goal file Linux in the main GOAL folder where you installed GOAL Run the goal bat Windows or the goal sh Linux OSX from the command line from within the main GOAL folder where you installed GOAL GOAL IDE GOAL IDE File Edit Run Debug 115 6 gt e xin a m x sw 4 Files 1 A I MAS Projects B Other files Consolex Info x Action log Re opening MAS projects Re opening other files Figure 3 1 The GOAL IDE window right after start up Starting the IDE should open the IDE window which should look similar to the one displayed in Figure 3 1 The IDE always first shows the edit perspective 9 10 CHAPTER 3 STARTING THE INTEGRATED DEVELOPMENT ENVIRONMENT The IDE window consists of four main parts Menu Bar At the top of the window the menu bar is located The menu provides various functions for file management editing MAS projects and running MAS projects Tool Bar The tool bar is located just below the menu bar The most important menu items are also accessible via buttons on the tool bar Content Area The area directly below the tool bar is called the content area On the left hand side of this area the files panel is shown in Figure 3 1 which
26. e IDE by default switches to the debug tracer of the agent that is being stepped This allows you to automatically keep track of what happens without having to manually switching between agent debug tracer tabs The 6 4 DEBUGGING OUTPUT 33 default switching between debug tracers can be turned of by means of the Help Preferences GUI menu uncheck the option at the bottom labeled Automatically switch to Debug Tracer tab Debug tracer tabs can be closed by clicking the close icon on of the tab You can re open a closed tab by selecting the agent in the process panel and righ clicking ctrl click on OSX and selecting Open Debug Tracer Customizing the Logging The logging behaviour of the IDE can be modified with Preferences Logging tab which is shown in Figure 6 3 The checkbox Show logs in IDE s console is the main controller that determines if the IDE shows all system information in the dedicated tabs If you turn off this checkbox all logs are instead printed directly to the console This can be helpful if you want to do special actions on the log text such as analyzing the steps or making an extensive bug report A timestamp with millisecond accuracy can be added to each printed log by checking the Show log time checkbox The write logs to file checkbox determines if GOAL writes all logs to separate files Logs for each agent the action log warnings results from GOAL log actions etc are all written to separate files
27. e wee NR RO EE ETTTPES 37 6 6 1 Exporting a Mental State to a File 38 6 6 2 Prolog Exceptions spaces u ko x RR a A 38 6 7 Runtime Preference 39 Gt Platform Management gt na duc A AA n m E don eor Pops 40 Gia Wares ee ne 41 7 Running in Stand Alone Mode 43 7 1 Setting the JVM environment leeren 43 12 FOM Jeu 22 22e aa 48 T From the Command Line s se i esc a 43 TA Runtime SUBES encia a a a A 44 7 5 Interaction with Standalone o e 44 TO Batch Running m AM Re Oe e A ee AAA 44 8 Creating Your Own Environments 45 8 1 Environments Distributed with 45 8 2 Creating an Environment 45 9 Known Issues and Workarounds 47 9 1 Issues o es 24 sa 6 n wo ra a e RAE Kok a bon Roa 48 Chapter 1 Introduction This user manual describes and explains how to e Install the GOAL platform e Start and use the Integrated Development Environment IDE that is distributed with GOAL e Runa MAS in stand alone mode without the IDE use this mode e g for running simulations and running the test framework and e Create your own environments that you can connect agents to using the Environment Inter face Standard EIS This document does not introduce the agent programming lang
28. ects M coffee mas2g coffeemaker goal coffeegrinder goal 9 bw2agents le stackBuilder goal le tableAgent goal 9 9 blocksworld 16 stackBuilder goal o E Other files goals pl Knowledge 2 block X on X _ 2 clear X block X not on X 4 clear table 5 tower X on X table tower X YI T on X Y tower YIT 7 beliefs agent stackbuilder 9 me stackbuilder 10 agent tableagent 39 percepts stackbuilder tableagent Initializing mental state of agent stackbuilder gent stackbuilder loaded successfully Initializing mental state of agent tableagent gent tableagent loaded successfully Launching Scheduler Scheduler initialized Figure 6 8 Export dialog for mental state contents 1 type error X Y an object of type X was expected but Y was found For instance in the context of arithmetic X can be evaluable and Y a non arithmic function 2 instantiation error the arguments for an operator are insufficiently instantiated For exam ple if we ask X gt 8 with X a free variable we will get an error like the example above The context in such a case would be context system gt 2 1425 The first part system gt 2 refers to the gt operator which has arity 2 and is part of the system module and the 1425 refers to the free variable which apparently was even anonymous hence is not of mu
29. el as follows The file itself as well as any child nodes in the Files panel are removed from that panel Note that removing a file from the Files panel does not delete the file from the file system Select Delete from the File menu to achieve this 4 2 5 Automatic Word Completion Automatic word completion is supported for both known keywords as well as for predicates or other words defined in the program Chapter 5 Running a Multi Agent System This chapter explains how to launch run and distribute a MAS project across multiple machines Running a multi agent system means launching or connecting to the environment the agents perform their actions in if any and launching the agents when appropriate As explained in Section 4 1 4 which environment is launched depends on the environment section of the MAS file that is being run Which agents are launched depends on the launch policy specified in the same MAS file Section 5 6 explains how to distribute one or more MAS across multiple machines GOAL IDE GOAL IDE File Edit Run Debug 2 gt wm 4 Edit 4 gt Process Overview bw2agents mas2g blocksworld blocksworld stackbuilder tableagent Console x Parse Info x Action log stackbuilder tableagent 73 milliseconds to load MAS initializing mental state connecting to entity gripper OK Welcome to the blocks worl
30. ents from other files into an agent program important reason for moving code to separate files and importing those files is to facilitate reuse After performing the procedure above the Files panel should look like Figure 4 5 A procedure very similar to that for knowledge files can also be used to move complete modules to separate module files with extension mod2g 18 CHAPTER 4 CREATING AND MANAGING MULTI AGENT PROJECTS GOAL IDE File Edit Run Debug 118 8 w x Files v MAS Projects N blocksworld mas2g v 8 stackBuilder goal bwKnowledge pl M mybw mas2g le stackBuilder goal tableAgent goal gt Other files 2 ijinit module knowledge import bwKnowledge pl beliefs on a table on b a on c b on d table on e table on f e on g on 1 0 on 2 1 on 3 2 on 4 0 on 5 0 on 6 5 on 7 6 on 8 7 actionspec not on X Y in precondition to prevent moving a block on the table to Y pre clear X clear Y Z not on X Y onsole Parse Info x Action log Re opening MAS projects Re opening other files File stackBuilder goal saved File bwKnowledge pl saved Figure 4 5 IDE after adding knowledge file import to the stackBuilder goal file After performing the procedure above the IDE should now look like Figure 4 6
31. f a GOAL agent select the agent process and then select Debug Export mental state This allows you to save the contents of a mental state as a Prolog file The exported file s can then be imported into a Prolog debugger SWI Prolog can be used for this provided that you installed SWI Prolog on your machine The version of SWI Prolog that is distributed with GOAL cannot be used for this purpose A detailed set of instructions on how to do this follows 1 select and pause the agent just before the point where you would like to debug a call to Prolog 2 select menu Debug Export Mental State contents and save the database contents as a ms MentalState file You can save beliefs and goals to a separate file and opening the exported file in the IDE but for opening in Prolog export to a single file seems most useful After clicking OK a file browser appears select a good place to save the file 3 Manually edit the ms files a They need to have the extension 1 to import in prolog b All predicates that you use but do not have explicit values in the prolog program may need to be declared dynamic See the SWI Prolog Manual for details c Goals are dumped to the ms files as a conjunct of predicates and this is not a legal notation in Prolog the least you have to do is to replace all commas within a single goal with dots d You may need to fix the goals Several goals may be in conflict when seen from SWI Prolog
32. handling Show logs IDE s console C Show log time O Write logs to files Overwrite old log files Write log files here Volumes documents EclipseWorkspaces Browse Warnings print format 5 Maximum number that same warning message is shown U Show Java details with warning messages C Show Java stack traces with warning messages Close Figure 6 3 The Logging Preference tab 34 CHAPTER 6 DEBUGGING A MULTI AGENT SYSTEM 6 5 Setting Breakpoints A useful way to trace what your agents are doing is to step the multi agent system and check how and which action rules are evaluated which actions are performed which percepts are received etc Stepping assumes natural breakpoints to stop an agent at In the GOAL IDE a number of such breakpoints have been pre defined These built in breakpoints facilitate stepping and tracing of what happens when an agent is executed A second alternative method to set breakpoints is by explicitly adding them to code lines in agent program files user can set breakpoints at various places in a program where the agent should stop when such a breakpoint is hit 6 5 1 Stepping and Global Breakpoints The first method to step an agent and halt at breakpoints is based on a set of built in breakpoints that relate to the reasoning cycle of an agent A list of these breakpoints is available in the Help Preferences Breakpoints menu which is displayed in Figure 6 4 en
33. has been added to the belief base and on b c has been deleted stackbuilder Database query true beliefbase2 on a table on b a on c b on d table ta stackbuilder Executed move b a stackbuilder Database query true beliefbase2 on a table on b a tonic b on d table ta stackbuilder Round 1 Figure 6 2 sample query 6 3 Executing an Action using the Introspector You can also execute actions from the Query area within the Introspector The actions that can be executed include i mental state actions which change the mental state of the agent adopt drop insert delete and ii user specified environment actions that are executed in the environment You cannot execute other actions such as combined actions sending messages or modules Make sure that the action is closed i e has no free variables To execute an environment action make sure that the environment is running You may also need to figure out whether the 32 CHAPTER 6 DEBUGGING A MULTLAGENT SYSTEM agent that should execute the action is allowed to perform an action at the time you want to perform the action e g it is the turn of that agent Note that an environment action is sent to the environment without checking its preconditions The postcondition of the action also is not processed nor are any percepts related to the action passed to the agent Fi
34. he main GOAL folder where GOAL was installed References to environments in a MAS file are resolved by checking whether the environment can be found relative to the folder where the MAS file is located or else an absolute path should be specified to the environment interface file The GOAL platform supports the Environment Interface Standard EIS to connect to environ ments 2 1 See Chapter 8 on how to develop an environment for creating your own environments Any environment that is compliant with the most up to date version of EIS that is supported can be used in combination with GOAL For connecting your agents to an environment that has been launched by another instance of the GOAL platform possibly on another machine check out Section 5 6 800 GOAL IDE GOAL IDE File Edit Run Debug rm g a lt 7 amp gt e Debi MAS Projects a m blocksworld mas i environment m Fr 2 insert a proper environment reference on the next line el stackBuilder c 3 env blocksworld blocksworld jar i 4 insert proper initialization parameters and values on the next line or remove it zy 5 init start 2 3 0 5 0 7 0 6 8 i true stackBuilder c 1 2 3 0 5 0 7 0 6 8 gu 6 tableAgent gc Xther files v slagent files 9 insert list of agent file references below 10 stackBuilder goal 11 tableAgent goal 12 13 i4 launchpolicy 15 insert app
35. her installations of SWI Prolog on your machine will not be affected by the installer 2 3 Uninstalling For uninstalling GOAL run the uninstaller that is located in the folder where you installed GOAL 1The installer will automatically detect whether the JVM you use is 32 or 64 bits and will install the corre sponding version of SWI Prolog 8 CHAPTER 2 INSTALLING THE GOAL PLATFORM Warning The uninstaller allows you to select Force the deletion of lt folder gt where folder is the directory where you installed GOAL If you select this option then all files as well as the folder itself are removed from the file system Note that this will also delete all changes you made to new MAS and agent files that you created environments that you installed and IDE preferences that you changed Note that if GOAL was installed with an administrator account it needs to also be de installed using that same administrator account If you try to de install without administrator rights the de installer will fail without any error message 2 4 Upgrading To upgrade the GOAL platform to a newer version first run the uninstaller see previous section but do not select the option to delete the installation folder and reinstall the platform as explained above You can also simply run the GOAL installer and select yes when you are asked whether you want to overwrite old files Simply running the installer however may not properly clean old setti
36. ironment can be found on the website for GOAL http ii tudelft nl trac goal wiki Developers Environments HowToEISifyAnEnvironment 45 46 CHAPTER 8 CREATING YOUR OWN ENVIRONMENTS Chapter 9 Known Issues and Workarounds Below we have listed some known issues and possible workarounds when available Nothing happens when pressing the Step and Run buttons There are a number of possible explanations for this you can check 1 First make sure that the environment is ready to run For example when using the Elevator environment the environment will respond to GOAL only if you selected GOAL Controller available in this environment 2 You may be stepping an agent that is suspended somehow e g the environment may be refusing to serve that agent or it may be the turn of another agent The environment does not work as expected Check the documentation that comes with the environment Most environments need to be set up before the agents can connect and perform actions The Wumpus environment hangs when the agent shoots an arrow The Wumpus World always has to be enclosed by means of walls If an agent shoots an arrow into open space the arrow will continue forever causing the system to hang The Reset button does not work It is not always possible to reset an environment as an environment may not provide the support for doing so I do not see an environment after launching a MAS The environment may be hidden behind the GOAL
37. is icon will be shown with some environments that do not provide information about their current state 5 2 RUNNING A MULTIAGENT SYSTEM 25 5 2 Running a Multi Agent System After an environment has been initialized a multi agent system can be run How to run a MAS e Select the MAS node in the Process panel e Press the Run button to run the multi agent system All processes including the environment and the agents must be in running mode to be able to run the complete multi agent system The symbol P indicates that a process is in running mode In running mode an agent will execute a complete reasoning cycle without pausing If the agents in a MAS are paused but the environment is not the environment still may be changing due to processes that are not controlled by the MAS or simply because actions take time durative actions Vice versa if an environment is paused but one or more agents in the MAS are running typically you will see complaints that the agent was not able to retrieve percepts from the environment 5 3 Terminating a MAS and or Its Agents In order to be able to terminate a MAS you must be in the Debug perspective You can select this perspective by clicking on the Debug button on the right hand side of the tool bar This button is only available if there is MAS running How to terminate a MAS or an Agent e Select the MAS or agent you want to kill in the Process panel e Press the Kill button in the too
38. l bar Terminating a MAS terminates the environment all agents and switches the perspective back to the Edit perspective Killing a single agent does not kill the MAS The X symbol indicates that a process has been killed An agent that has been killed is not performing any actions any more If a killed agent is put back in running mode the agent is restarted and initialized using the initial mental state specified in the agent program agent will also be automatically killed if the entity that it is controlling in an environment has been terminated Agents that are not associated with an entity are only killed if the user kills it 5 4 Run Modes of a MAS and Its Agents A MAS or agent can be either in the running stepping paused or killed mode Controlling the run mode of a process is done with the Run Step P Pause and Kill X buttons in the tool bar Alternatively you can either use the Run menu or select a process and right click ctrl click on OSX to set the run mode You can control all processes that are part of the MAS at once by selecting the mas process node and using the relevant buttons This is particularly useful when starting stepping or killing all agents The following symbols are used to indicate the run mode of a process e indicates that the process is paused e indicates that the process is running 26 CHAPTER 5 RUNNING MULTI AGENT SYSTEM e indicates that a process is in stepping mode
39. multiple runs of the MAS files To enable proper batch running your setup has to meet two requirements e Your MAS terminates at some point This happens when all agents have terminated e g exited their main program section or were killed e Your environment resets the entities when it is killed and then restarted This may seem natural but in some configurations eg BWAT 2 killing and restarting a local environment does not necessarily reset the real remote environment Chapter 8 Creating Your Own Environments 8 1 Environments Distributed with GOAL GOAL is distributed with several environments for which you can write your own agents These environments can be found in the GOALagents folder in the main GOAL folder in which GOAL is installed Running these environments is explained in Chapter 5 8 2 Creating an Environment Interface Environments provide so called controllable entities Agents can connect via an interface to these entities and control their behaviour The GOAL Programming Guide 3 explains in more detail how this works The interface used by GOAL is the Environment Interface Standard EIS 2 1 The current version of the GOAL platform is fully compliant with EIS v0 3 EIS is an Open Source project and documentation on how to create an interface for your environment such that it can operate in combination with GOAL is available via http sourceforge net projects apleis Ad ditional guidelines for creating an env
40. n overview of what has been done by agents the action log can also be used as a simple means for debugging It can be used for example to check whether a particular action added for debugging has been performed The idea is that you can add a dummy action with a particular content message to a rule and verify in the action log whether that action has been performed To do so include an action in the action specification of your agent named e g debug lt yourMessage gt with true as pre and post condition to ensure the action always can be performed and will not change the state of the agent but still will be printed in the action log output Debug Tracer Upon launching an agent a debug tracer tab is added for that agent in the feedback area This tab typically contains more detailed information about your agent avoid flooding the tab it is only filled however when the multi agent system is paused To be useful the contents of the tab need to be analyzed which cannot be done while new content would be added continuously The exact contents of the tab can be customized by means of the Help Preferences Breakpoints settings menu Various items that are part of the reasoning cycle of an agent can be selected for viewing If checked related reports will be produced in the debug tracer of an agent more detailed explanation of these breakpoints can be found in Section 6 5 If you step a multi agent system using the Step button gt th
41. nally no feedback is provided whether an action was successfully performed or not 6 4 Debugging Output In debug mode the feedback area in the IDE contains various tabs for inspecting agents and the actions they perform see Figure 5 1 Besides the console tab an action log tab is present that provides an overview of actions that have been performed by all running agents In addition when an agent is launched a debug tracer tab is added to the feedback area for inspecting various aspects of the agent program during runtime It is sometimes useful to clean the contents of a tab This can be done by right clicking ctrl click on OSX and selecting the Clear option This is particularly useful for the action log which is never automatically cleared Console The console shows all important messages warnings and errors that may occur while using the IDE These messages include those generated by GOAL at runtime but possibly also messages produced by environments and other components When something goes wrong it is always useful to inspect the console tab for any new messages If a new message is present in the console tab the color of the tab is changed to indicate this Action Log The action log tab shows the actions that have been performed by running agents that are part of the multi agent system These actions include both user defined actions that are sent to the environment as well built in actions provided by GOAL Apart from a
42. nces panel for Platform Manager 6 7 1 Platform Management The tab PlatformManager in the Help Preferences menu offer a number of options to set the base path for the environment and middleware This preference window offers the option to always run the middleware locally This checkbox is by default disabled and therefore when starting a mas you will always be prompted for the location of the middleware host If you turn on this checkbox the default localhost will be used as middleware host and the dialog will not be shown You can adjust the directory where browsing for mas2g and goal files will start and whether your last directory should be used as the starting point for browsing The default KR Language selection allows you to choose between the default swiprolog imple mentation and an alternative swiprolog2 implementation swiprolog2 attempts to compile mental state queries into a single query to the underlying swi prolog engine This implementation is not fully tested and it is recommended to use swiprolog Selecting the sleep agents when they repeat same action enables GOAL to skip agents that seem to be idle which relocates CPU time to other agents that really are working on something GOAL guesses that an agent is idle if the agent is receiving the same percepts and mails as last step on the input and picks the same actions as output The sleep is cancelled when the percepts mails of the agent change This setting
43. ngs in the registry on Windows 2 5 Installation for Admins GOAL can be installed in the Program Files directory or another shared directory on OSX or Linux so that multiple users can share the same installation The GOAL installer is not fully prepared for installation on Windows 7 in the Program Files directory or any other directory with restricted access because of some limitations of the installer we use To install in such a directory you need to log in as administrator or manually switch to administrator mode On Windows 7 this works as follows 1 Right click on Start menu All programs Accessories Command prompt and select Run as administrator 2 Select Yes when Windows asks you Do you want to allow the following program to make changes to this computer 3 In the Command Line Console that opened type cd lt installerDirectory gt where lt installerDirectory gt is the directory where you downloaded the goalxxx jar installer and hit Enter 4 Type in java jar lt goalxxx gt jar where lt goalxxx gt is the name of the installer file and hit Enter 5 Perform the steps required for installation Select the required protected directory as install directory e g C Program Files GOAL Chapter 3 Starting the Integrated Development Environment GOAL is distributed with an integrated development environment IDE that supports the creation managing running and debugging of multi agent systems You can start th
44. o GOAL Preferences Breakpoints Logging Introspector PlatformManager gt Breakpoint View Pause All debug messages Steps the reasoning cycle of the agent The round separator Mails received LJ Percepts received Evaluation of action rules Evaluation of action preconditions Built in actions that have been executed Actions that were executed and sent to the environment Changes to the belief base Changes to the goal base Goals that have been achieved Results of atomic queries bel goal a goal and goal a Results of raw database queries ICQ COE 000E El DODODOOODOWOaon Figure 6 4 Setting Global Breakpoints There are two columns with check boxes that are labeled View and Pause If the View check box of a breakpoint is checked a report related to the breakpoint will be made available in the Debug Tracer of an agent If the Pause check box of a breakpoint is checked all agents will be paused when such a breakpoint is hit We briefly discuss each of the available built in breakpoints e The first item Steps in the reasoning cycle of an agent relates to e g the start of the agent s reasoning cycle By default a round separator is added to the output in the Debug Tracer to indicate which reasoning cycle round has been executed This round separator is also available in the action log e The items Mails received and Percepts received concern the events of receiving new mails and
45. ocess icon indicating that a process is running on a remote platform The IDE only allows introspection and debugging of local agent processes GOAL IDE File Edit Run Debug GOAL IDE File Edit Run Debug ufo alx s 8 tae Ela el oy jeixim a r w x w 8 Tr Process Overview Process Overview elevator mas2g elevator2 mas2g elevator 2 elevator 2 elevator 3 elevator 3 9 elevator 4 9 elevator 4 elevatorenv elevatorenv Received new entity named car2 initializing mental state connecting to entity car2 OK ook 88 milliseconds to load MAS trying to create registry Figure 5 3 IDE for machine 1 Figure 5 4 IDE for machine 2 If you take down the second MAS the entities will be released and can be reused by other still running MASs If you take down the MAS that launched an environment the environment will be taken down removing all associated entities All agents associated to these entities will then be killed 28 CHAPTER 5 RUNNING MULTI AGENT SYSTEM Chapter 6 Debugging a Multi Agent System The IDE provides various options for debugging Some of these tools relate to agent code itself such as the warnings and error reports
46. or errors have been produced When you launch a multi agent system GOAL will not start the system when one or more program files contains an error Apart from the need to remove parsing errors it is also better to clean up program files and make sure that no warnings are present Note A multi agent project can only be launched if no other multi agent system is currently running If another MAS is running the Run button in the tool bar in edit mode is disabled In order to start a new MAS you first need to kill the MAS that is running 5 1 1 Initializing an Environment In order to actually run a MAS it may also be necessary to initialize an environment by means of the environment s user interface In the UNREAL TOURNAMENT environment for example you can create new bots that can be controlled by agents Please consult the environment documentation for details Depending on the configuration and launch rules of your MAS file new agents are automatically created when a new bot is added Refer to the Programming Guide for more information on this 3 Note that environments often also have entities that cannot be controlled by agents such as people taking the elevator in the Elevator environment or UNREAL bots that are controlled by the UNREAL engine itself 1The status of the environment as indicated by the icon next to the environment process name may not always be known In that case the icon may be shown to indicate the state is unknown Th
47. part of a mas that has been launced At the far right of the tool bar you find the mode button that facilitates switching between the two modes of the IDE Switching between modes is only possible if a mas has been launched 6 6 PROLOG LEVEL DEBUGGING 37 GOAL IDE File Edit Run Debug Sniffer 2 518 Wj d x 2 Files MAS Projects 8 elevator mas2g some L Note that no actions can be performed when a car is moving il When the elevator arrives the Dir light will turn on elevatorager wr goto Level Dir pre atFloor L dir D post not dir D dir Dir 35 main module program order random generally we change our plans only while we are docked that is at a Adopt new stops that are on this agent s route at random if all agent adoptions That is give priority to informing agents about adopting if bel fButtonOn L D onRoute L D then adopt atFloor L dir D Y If there are no current goals to pursue then adopt a goal to service Console _ Parse Info x Action log tity event for entity named of type car Received new entity event for entity named carl of type car Received new entity event for entity named car2 of type car GOAL Controller Multi agent system elevator mas2g has been terminated scheduler run ended Figure 6 6 An ALWAYS and a CONDITIONAL Breakpoint a
48. placed with a on Linux and OSX e on Windows PATH should be set to include GOALHOME swifiles libs On Linux you should set LD_LIBRARY_PATH instead and on OSX you should set DYLD_LIBRARY_PATH e SWI_HOME_DIR should be set to point to GOALHOME swifiles e JAVA_LIBRARY_PATH should be set to include GOALHOME swifiles libs e CLASSPATH should be set to include GOALHOME goal jar and to the EIS environment jar file that you want to use You can inspect the goal bat Windows or goal sh file Linux OSX to see a running example of the above 7 2 From Java Running a stand alone MAS from Java is very simple just create the goal tools Run object from Java and start it using this call new Run new File fileName run where fileName is the MAS file that you want to run 7 3 From the Command Line To run GOAL stand alone from the command line the typical call looks like this 43 44 CHAPTER 7 RUNNING IN STAND ALONE MODE java cp goal jar Djava library path swifiles libs goal tools Run lt filename mas2g gt wait where lt filename mas2g gt is the absolute path to the MAS file you want to run You can add the wait option so that the runner waits between starting the environment and scheduling the GOAL agents see Section 7 5 below d debug Display out put from debugger while running agent Print messages from error h help Displays this help 1 Print messages from info license Shows the license
49. provides an overview of files associated with MAS projects The right hand side of the area is used for editing files Feedback Area The area at the bottom is called the feedback area Text messages and errors are displayed in this area grouped in various tabs 3 1 Keyboard Shortcuts Many menu items have associated keyboard shortcuts The keyboard shortcuts if available are shown behind the items in the menus 3 2 Feedback Area The feedback area is an important area to keep track of what is going on while creating managing or running a MAS project The area consists of several tabs that are always present and some tabs that are only present when running a MAS Console The Console tab provides general feedback but also notifies of major issues with a MAS or environment for example If you do not understand the behaviour you see always check out this tab Parse Info The Parse Info tab provides information about syntax errors and other issues that were noticed while parsing your MAS and agent files The Console also reports that errors have been noticed while parsing but you need to check out the Parse Info tab to see which errors were found The tab also displays warnings that do not prevent running a MAS but should be fixed nevertheless Action Log The Action Log tab keeps a record of the most recent actions that have been per formed by agents while running a MAS The tab in a sense provides a summary of what has happened while exec
50. r goal 8 on a table on b a on c b on d table on e table on f e on g f or x E 9 on 1 0 2 1 on 3 2 on 4 0 on 5 0 on 6 5 on 7 6 on 8 7 on 9 B bwKnowledge pl 10 M bwEvent mod2g Y n actionspec 8 tableAgent goal 12 not on X in precondition to prevent moving a block on the table to anotr x _ 13 nove X Y gt 5 Other files 14 pre clear X clear Y on X Z not on X Y 15 post not on X Z on X Y 16 17 44 21 program order random 22 define nisplaced X a goal tower X T 23 define constructiveMove X Y a goal tower X Y T bel tower Y T 24 25 if constructiveMove X Y then move X Y 26 if nisplaced X then move X 0 Consolex Parseinfo Actionlog Parsing of tableAgent goal completed 15 35 56 Parsing agent file Volumes documents EclipseWorkspaces GOAL GOALagents BlocksWorld stackBuilder goal Parsing of stackBuilder goal completed 23 13 Figure 4 6 IDE after adding a module file import to the stackBuilder goal file 4 2 Managing an Existing Multi Agent Project Loading a multi agent system project simply means opening a mas2g file You can do this by selecting the File Open menu locating a mas2g file and opening it Example MAS projects are provided with the distribution of GOAL in the GOALagents directory This directory is created in the main GOAL directory when the pl
51. ropriate launch rules for your environment and agents below 16 when entity env do launch stackbuilder stackBuilder tableagent tableAgent 17 18 19 j NS lt gt Consolex _ Actionlogx Parsing of stackBuilder goal completed 15 13 03 Parsing agent file Volumes documents EclipseWorkspaces GOAL GOALagents BlocksWorld tableAgent goal Parsing of tableAgent goal completed Ra 7 1 Figure 4 4 Edited Launch Policy in bw2agents mas2g 4 1 4 Adding a Launch Policy In order to create agents when a multi agent system is launched a launch policy for creating the agents is needed launch policy is a set of rules which specify when to launch an agent 41 CREATING A NEW MULTI AGENT PROJECT 17 A launch instruction creates and adds a new agent to the MAS when the MAS is launched A launch rule only creates an agent when a controllable entity in an environment becomes available i e when the GOAL platform is notified that an entity has been born Agent name and agent file name can but do not have to be different Finally more than one agent can be connected to a single entity The GOAL Programming Guide 3 provides a comprehensive explanation of launch policies 4 1 5 Importing Knowledge and Module Files When you start writing larger agent programs it is often useful to add more structure to the MAS project GOAL provides the import command to import cont
52. rrently provides two alternative messaging platforms Local messaging and a messaging based on RMI The local middleware is selected by default since the performance of the local middleware usually outperforms that of RMI But to run a truly distributed agent system you need to select RMI Messaging Use the Run menu to select one of these 5 6 2 Distributing MAS It is possible to connect a MAS to an existing environment that is already running in another instance of the GOAL platform This can happen for example when a second MAS is run using a second instance of the GOAL platform To do this you provide a reference to the name of the already running environment e g env elevatorenv The name is derived from the jar file name and gets a serial number added to it if you launch multiple of them If you connect multiple MASs to a single environment the second MAS will only be able to connect to entities that are still free A GOAL multi agent system can be run in a truly distributed fashion having various agents running on different JVMs and or on different machines In this case there is one main platform that is the access point for the other platforms The main platform has to be launched first after which the other platforms can join Currently only RMI supports distributed running 5 6 DISTRIBUTED RUNNING OF ONE OR MORE MAS 27 You should have two GOAL IDEs running similar to Figure 5 3 and Figure 5 4 Note the remote pr
53. s documents EclipseWorkspaces GOAL GOALagents HelloWorld agentfile goal Figure 4 3 Edited MAS File Hello World Example mas2g 4 1 2 Using the File Menu to Create a New Agent File You can also create a new agent goal file by means of the File New menu The new agent file may not automatically appear below the selected MAS file in the Files panel That only happens if the agent file name is already present in the agentfiles section of that MAS file In case the agent file reference is not present in that section the agent file that is created will appear below the Other Files node Add the agent file reference to the MAS file to make it appear below the MAS file node 4 1 3 Adding an Environment to a MAS Project An environment is added to a MAS project by editing the environment section in a MAS file Note that the environment section is optional and that a multi agent system can be run without an environment 16 CHAPTER 4 CREATING AND MANAGING MULTI AGENT PROJECTS e Add env lt environmentname gt jar to the environment section in the MAS file e If the environment supports initialization parameters check the documentation that comes with the environment add init lt key value gt to the environ ment section in the MAS file here where key is the name of the parameter and value the value you choose to initialize the environment with Several environments are available in the GOALagents folder in t
54. sked to provide a new MAS file name by selecting the MAS Projects node in the files panel and then using the File New menu When a new MAS file is created MAS template is automatically loaded This template inserts the the sections that are required in a MAS file with some initial content you should adapt the content of these sections of the MAS file to your needs MAS file must have an agentfiles and launchpolicy section an environment section is optional The template also inserts a reference to an agent file called agentfile goal which triggers a dialogue in which you are asked whether you want to create this file In most cases you will select no because you want to modify the name of the agent file After saving the MAS file you should see something similar to 800 GOAL IDE GOAL IDE File Edit Run Debug 5 m 2 Je 5 Je gt m q i Debt 6 7 4 8 Files Hello World Example mas2g x v B MAS Projects Hello World Example mas2g 1 gt B Other files 3 4 5 launchpolicyf Console x Parse Info Action log x Re opening MAS projects Re opening other files Ars WARNING Found parsing errors in Volumes documents EclipseWorkspaces GOAL GOALagents HelloWorld Hello World Example mas2g Figure 4 2 New MAS File Template The warning displayed in the Console area appears because the agentfile goal does not exist This iss
55. structs in an agent program a module the condition of an action rule the action part of an action rule and an action specification Breakpoints can be added to these constructs by opening a mas project file in the editor and adding breakpoints at the first line associated with the construct That is put a breakpoint next to the line with the module name the first line associated with an action rule or the the line with the action name You can do this by right clicking in the left border of the editor and selecting Add breakpoint GOAL will relocate incorrectly placed breakpoints to their appropriate position when the MAS is started This is done by attaching an incorrectly placed breakpoint to the first suitable location after its current position There are two types of breakpoints the ALWAYS and the CONDITIONAL type A CONDI TIONAL breakpoint shows as an orange tag in the left border It can only attach to the action part of an action rule The ALWAYS type shows as a red tag in the left border and attaches to the other three types 36 CHAPTER 6 DEBUGGING A MULTI AGENT SYSTEM GOAL IDE c5 File Edit Run Debug Sniffer Help rocess Overview bw2agents mas2g E Blocks World Beliefs Goals Mails Percepts Knowledge Mus n a table on b a on c b on d table on e table on f e on g on h g on i h ar _ stackbuilder
56. tem 5 1 Launching a Multi Agent System SLi Initializing an Environment 222522999 eo oos certera 5 2 Running a Multi Agent System 5 8 Terminating a MAS and or Its 0 5 4 Run Modes of a MAS and Its 5 5 Resetting a MAS and Its Environment a a 5 6 Distributed Running of or More 5 6 1 Messaging Infrastructures 4 56 2 Distributing MAS soc REO rer a aa mmm E Ed 00 00 1 NNN 10 10 10 13 13 14 15 15 16 17 19 20 21 21 22 22 4 CONTENTS 6 Debugging a Multi Agent System 29 6 1 Introspecting Agents o 2228 oe Rx aaa nee 29 56 1 Querying a Mental State 4 5a 2 8 E om Ra BERGE E RES h EO 30 6 3 Executing an Action using the Introspector 3l BA Debes Output coo saciar IR RR UR SE X 32 dol AAN 32 SUI GS nud dos ox w b ud ERE RUE RR 32 Debug s e s sa x m o E SR e ee 32 Customizing the Lopping 22292 nenne 33 Da Breakpoints xo sss xou RE yos ee we e UA OR d E Tee 34 6 5 1 Stepping and Global 5 34 6 5 2 Setting Code Line Breakpoints 35 6 5 3 Switching Between Edit and Debug Mode 36 66 Prolog Level Debugging 52 oe e
57. that are output to the Parse Info window in the Feedback Area and the Static Code Analysis tool provided in the Debug menu GOAL also provides a model checker to verify whether an agent satisfies desirable properties While running a mas the IDE provides a range of options for debugging which include the following 1 options for viewing and controlling debug output produced while running a mas 2 setting general and specific breakpoints to pause an agent on 3 agent introspectors for inspecting the mental state of an agent and percepts and messages received at runtime 4 a message sniffer for tracing messages that are exchanged between agents currently only when running the JADE middleware TODO The IDE facilitates debugging of a multi agent system in various ways It provides various forms of feedback in the feedback area at the bottom of the IDE in debug mode i e when a multi agent system is running In addition for each agent an introspector can be opened to inspect the contents of the mental state of an agent Finally it is possible to set breakpoints to pause an agent when it hits such a breakpoint 6 1 Introspecting Agents A useful tool to trace what your agents are up to is the introspector An introspector allows you to inspect the mental state of an agent How to open an Introspector e Open an introspector by double clicking on an agent process in the Process panel or e Alternatively select the agent process
58. uage GOAL itself For this we refer the reader to the GOAL Programming Guide 3 and GOAL s website 4 CHAPTER 1 INTRODUCTION Chapter 2 Installing the GOAL Platform This chapter explains how to install the GOAL platform We first describe the system requirements of the platform Please verify that your system meets the minimal system requirements 2 1 System Requirements The GOAL platform runs on Windows Macintosh OSX and the Linux operating system For in formation on the exact versions of these OSs please check GOAL s website at http ii tudelft nl trac goal On this website you can also download the latest version of the installer for the GOAL platform The GOAL platform requires Java SUN or OpenJDK version 1 6 or higher We recommend to use Sun Java We have found that some other versions of Java fail to run the installer 2 2 Installation Install GoAL by using the installer for GOAL that you can download from http ii tudelft nl trac goal Run the installer and follow the instructions Run the installer either by e Double clicking on the jar file or e Open a Command Line Console and from the folder where the installer is located run the command java jar lt goalinstaller jar gt where lt goalinstaller gt is the name of the installer file It is recommended to install all files including e g SWI Prolog by the installer This will ensure that the right version of SWI Prolog is available to run GOAL Ot
59. ue needs to be fixed before we can launch the MAS 4 1 1 Adding an Agent File to a MAS Project How to add a new agent file to a MAS project edit the MAS file e Add lt agentfilename gt goal to the agentfiles section in the MAS file e Save the MAS file using the File Save menu or CTRL S APPLE S e Select yes when asked whether you want to create the agent file If you just created a new MAS file simply modify the initial agent file agentfile goal inserted by the template in the agentfiles section Save a file either by using the File Save menu or by pressing CTRL S Windows and Linux or APPLE S OSX This will save the file you have selected in the content area the active tab After adding a new agent file the IDE should look similar to Figure 4 3 Tf you add a new agent 41 CREATING A NEW MULTI AGENT PROJECT 15 file that does not yet exist you are asked to confirm that you want to create it A new agent file is automatically loaded with a corresponding template GOAL IDE File Edit Run Debug agentfile goal x Projects lo Ward Exan 1 agentfiles PC clado led 2 agentfile goal agentfile goal 3 E Other files 4 5 launchpolicy 6 when entity env do launch agentfile agenttfile 78 8 Infox Action log WARNING Found errors in Volumes documents EclipseWorkspaces GOAL GOALagents Helloworld Hello World Example mas2g WARNING Found errors in Volume
60. uting the MAS Agent The Agent tab with the name of the corresponding agent as title displays detailed debug information about the agent program that is being executed The information that this tab provides can be customized via the Preferences menu 3 3 Customizing the IDE Various aspects of the IDE interface can be customized various platform features can also be customized e g debugging features How to customize the IDE interface e Select Help Preferences Windows Linux or GOAL IDE Preferences OSX e Select the GUI amp Files tab in the Preference menu 3 3 CUSTOMIZING THE IDE 11 Q GO Preferences Runtime Breakpoints Logging GUl amp Files Database Export Java Look and Feel changes take effect after restart File Handling Start browsing for agent files here Volumes documents EclipseWorkspaces GOAL GOALagents BlocksWorld M Remember last used agent directory M Re open Mas Projects at start up M Re open Other files at start up Window Sizing and Settings M Remember IDE window size M Remember IDE window position i2 Font size in CONSOLE area changes take effect after restart Remember size of CONSOLE area 500 Maximum number of lines in CONSOLE area changes take effect after restart M Remember the size of the database view area in INTROSPECTOR M Single size of query area in INTROSPECTOR 100 Maximum number of lines in query output area in INTROSPEC
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