Re: Simple Simulation problem

[Paul Johnson]

It worked better for you to post the file and refer us to it. Please 
don't attach binaries that get sent to the whole list.

I have your new simulation.zip and I'm working with the system where I 
built swarm and the irritating c++ dependency is fixed.  When I run your 
program, I see this:

$ javaswarm StartSimulation
SimpleBug number 1 has been created at 40, 0
SimpleBug number 2 has been created at 40, 80
Exception in thread "main" java.lang.NullPointerException
        at ObserverSwarm.buildObjects(ObserverSwarm.java:85)
        at StartSimulation.main(StartSimulation.java:14)

Which is the system's way of telling you that you sent a message to a 
nil object. If I were you, I would find out how to run a debugger. 
Today, I'm not able to get gdb to work as the SwarmFaq describes, but I 
can get to jdb, and it points back at line 85 of ObserverSwarm.java

Note you are giving these instructions to objects that are not yet created
      a1bug.setBugColor((byte)1);
      a2bug.setBugColor((byte)2);


To make this work, you either have to set the colors inside ModelSwarm 
itself, which you can do by moving those two lines into ModelSwarm right 
after your 2 agents are created,  or make the variables public and talk 
to them directly from Observer, as in:
    modelSwarm.a1bug.setBugColor((byte)1);
    modelSwarm.a2bug.setBugColor((byte)2);


After that change, I see a raster that's not quite what you intend--not 
updated or drawn on properly--and terminal output like

$ javaswarm StartSimulation
SimpleBug number 1 has been created at 40, 0
SimpleBug number 2 has been created at 40, 80
Agent 1 is at 40, 79
Agent 2 is at 41, 79
Agent 1 has found Content of 1 at 41, 0
Agent 1 is at 41, 0
Agent 2 is at 42, 78
Agent 1 has found Content of 1 at 41, 0
Agent 1 is at 41, 0
Agent 2 is at 41, 77
Agent 1 is at 41, 1
Agent 2 has found Content of 1 at 40, 77
Agent 2 is at 40, 77

I'd suggest you join the Swarm Development Group if you want me to do 
any more of this kind of detailed work.


Trushar Panchal wrote:
> Hi Paul,
>
> Thanks for your advise. I am sending you the zip file as you requested. 
> Also I missed to initialise the file Agent1/2.java with int a=0; which 
> i have done. I use Win 2000 and java. It compiles without any problems 
> and comes up with the Control Panel but the Display window and the 
> Probe Windows are not coming up. Once I click 'Start' this is the two 
> output i get.



--
Paul E. Johnson                       email: address@hidden
Dept. of Political Science            http://lark.cc.ku.edu/~pauljohn
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66045                FAX: (785) 864-5700


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