[Repast-developer] Re: hiding the schedule

[Laszlo G. <gu...@la...>]

Hi,

First of all, I liked the SimpleModel class pretty much, so thanks for the 
good work.
I'll give it some more thoughts during the coming days, though...

At this point, the only thing which came up was the scrambling of the
agentList before each autoStep, in order to have the order in which the
agents are called randomized. I wonder whether this should also be automated.
I understand that you could do that in preStep(), but may be, having a flag 
for that,
too would be even easier.

Best,

Gulya


At 02:42 PM 9/6/01 -0400, Nick Collier wrote:
>Hi,
>
>I've attached the first cut of a base model class that attempts to hide 
>the scheduling mechanism. (For those of you tuning in late, this is for 
>teaching purposes although its probably applicable to a lot of current 
>models as well). Its based on the tutorial TemplateModel by Lars-Erik and 
>Gulya. The idea here is that the user subclasses SimpleModel and 
>implements or overrides a few methods while SimpleModel takes care of the 
>scheduling.
>
>The important pieces here are:
>
>1. The run*(), and *step() methods. The idea here is to split up the 
>behavoir executed each tick into pre (preStep()), post (postStep()), and 
>executing (step()) phases. So in the case of a cooperation game, the user 
>would override the step() method to have the agents play the game, and the 
>preStep() and postStep() would do any necessary prepartion or destruction. 
>What actually executes each tick is preStep(), step() and then postStep().
>
>If autoStep is set to true, SimpleModel will execute the preStep(), 
>autoStep() and then postStep(). autoStep() loops through the agent list 
>calling step on each agent. For this to work the agents must implement the 
>Stepable interface.
>
>2. The stopping time stuff. This was in the TemplateModel code so I 
>assumed it was important and implemented it. The idea here is that the 
>user can set the stopping time via a call to setStoppingTime in their 
>model, and SimpleModel will schedule the model to stop when that tick has 
>completed.
>
>So, is this enough? Do we need to include some random number 
>initialization? Should SimpleModel be abstract and force people to 
>implement buildModel()? Any other thoughts, comments, etc. are of course 
>welcome.
>
>Nick
>
>
>Lars-Erik Cederman wrote:
>>Nick: This sounds like music to our ears! When do you think you might be 
>>done with this new version? Gulya and I will be teaching RePast as of 
>>October and we're obviously very keen to have a standardized hiding mechanism.
>>We'd be more than happy to contribute ideas and code so that we can get 
>>this one up and running very soon.
>>I should mention that Gulya has now arrived in Cambridge. His email 
>>address is gu...@la....
>>Cheers, L-E
>>
>>
>>>Hi,
>>>
>>>I'm thinking for the next release of repast I'll add something along the 
>>>lines of your tutorial model that hides the scheduler, and assumes a 
>>>step method in the agents. I'd appreciate your thoughts on this.
>>>
>>>thanks,
>>>
>>>Nick
>>>
>>>--
>>>Nick Collier
>>>Social Science Research Computing
>>>University of Chicago
>>>http://repast.sourceforge.net
>>
>
>
>--
>Nick Collier
>Social Science Research Computing
>University of Chicago
>http://repast.sourceforge.net
>
>
>
>package uchicago.src.sim.engine;
>
>public interface Stepable {
>
>   public void step();
>
>}
>package uchicago.src.sim.engine;
>
>import java.util.ArrayList;
>
>public class SimpleModel extends SimModelImpl {
>
>   protected Schedule schedule;
>   protected ArrayList agentList;
>   protected String name = "A RePast Model";
>   protected String[] params = {""};
>   private long stoppingTime = -1;
>   private BasicAction stoppingAction;
>   protected boolean autoStep = false;
>
>   public void setStoppingTime(int time) {
>     stoppingTime = time;
>     if (stoppingAction != null) schedule.removeAction(stoppingAction);
>     if (schedule != null) setStopAction();
>   }
>
>   private void setStopAction() {
>     System.out.println(stoppingTime);
>     schedule.scheduleActionAt(stoppingTime, this,"stop", Schedule.LAST);
>   }
>
>   public void setup() {
>     stoppingTime = -1;
>     stoppingAction = null;
>     schedule = new Schedule();
>     agentList = new ArrayList();
>   }
>
>   public void begin() {
>     buildModel();
>     buildSchedule();
>   }
>
>   public String getName() {
>     return name;
>   }
>
>   public Schedule getSchedule() {
>     return schedule;
>   }
>
>   public String[] getInitParam() {
>     return params;
>   }
>
>   public void buildModel() {}
>
>   public void buildSchedule() {
>     if (autoStep) schedule.scheduleActionBeginning(1, this, "runAutoStep");
>     else schedule.scheduleActionBeginning(1, this, "run");
>     setStopAction();
>   }
>
>   public void runAutoStep() {
>     preStep();
>     autoStep();
>     postStep();
>   }
>
>   public void run() {
>     preStep();
>     step();
>     postStep();
>   }
>
>   private void autoStep() {
>     int size = agentList.size();
>     for (int i = 0;i < size; i++) {
>       Stepable agent = (Stepable)agentList.get(i);
>       agent.step();
>     }
>   }
>
>   protected void preStep() {}
>   protected void step() {}
>   protected void postStep() {}
>
>   public static void main(String[] args) {
>     SimInit init = new SimInit();
>     SimpleModel model = new SimpleModel();
>     if (args.length > 0) init.loadModel(model, args[0], false);
>     else init.loadModel(model, null, false);
>   }
>
>}
>
>
>
>
>
>
>
>
>
>

--
Laszlo Gulyas, MSc
Government Department   Weatherhead Center for International Affairs
Harvard University              602C Coolidge Hall
1737 Cambridge street           Cambridge, MA-02138