Re: [Swarm-Support] (no subject)

[mariem siala]

Thank you for a response. I want an example in Objective-C .

----- Original Message ----- 
From: "LRA" <address@hidden>
To: "Swarm Support" <address@hidden>
Sent: Tuesday, December 13, 2005 4:20 PM
Subject: Re: [Swarm-Support] (no subject)


> mariem siala wrote:
> > Hi !
> > We can build agents in Model or Observer.
> > But How an agent can create another agent? Have you an example?
> 
> Hello,
> 
> Yes, agents can create new agents. You can program agents to call their 
> own "create" or constructor methods to reproduce.
> 
> There is one tricky part: You cannot add (or remove) agents from the 
> model's list of agents while the model's schedule is acting on that 
> list. (If the model is going through its list of all the StupidBugs and 
> telling them each to "grow", by using "createActionForEach", the bugs 
> cannot add new bugs to that list until the createActionForEach has 
> finished.)
> 
> Instead, new agents are usually put on a list of new agents. The model 
> then must have a scheduled action that takes the new agents off that 
> list and put them on the master agent list.
> 
> Do you want an example in Objective-C or Java Swarm?
> 
> Steve Railsback
> 
> public class StupidBug {
> 
> ...
> public void grow() {
> HabitatCell myCell = (HabitatCell)myCellWorld.getObjectAtX$Y(myX,myY);
> double cellFoodAvailable = myCell.getCellFoodAvailable();
> double foodEaten = Math.min(cellFoodAvailable, 
> modelSwarm.getBugMaxConsumptionRate());
> myCell.setCellFoodAvailable(cellFoodAvailable - foodEaten);
> mySize += foodEaten;
> 
> // For version 12, add reproduction to the grow method
> // When we create offspring, we use a new StupidBug constructor method
> // New bugs can die during their creation (if they do not find
> // a vacant cell) so we need to be careful ordering cleanup
> // of bug lists in the model swarm
> if (mySize >= 10.0) {
> // First make 5 more bugs
> StupidBug newBug;
> for (int i = 1; i <= 5; i++) {
> newBug = new StupidBug (myBugWorld, myCellWorld, modelSwarm, myX, myY);
> modelSwarm.add(newBug);
> }
> 
> // Then die
> myBugWorld.putObject$atX$Y(null, myX, myY);
> modelSwarm.remove(this);
> }
> return;
> }
> 
> ...
> 
> // Here is the new constructor method used for reproduction
> public StupidBug (Grid2dImpl aBugSpace, Grid2dImpl aCellSpace, 
> StupidModelSwarm aModelSwarm, int momsX, int momsY) {
> myBugWorld = aBugSpace;
> myCellWorld = aCellSpace;
> modelSwarm = aModelSwarm;
> mySize = 0.0;
> neighborCellList = new ListImpl(modelSwarm);
> 
> int testX, testY, testCellX, testCellY;
> int moveDistance = 3;
> HabitatCell newCell;
> 
> // To find a new location, make a list of available cells
> // This approach is copied from "move"
> neighborCellList.removeAll();
> for (testX = momsX - moveDistance; testX <= momsX + moveDistance; 
> testX++) {
> for (testY = momsY - moveDistance; testY <= momsY + moveDistance; 
> testY++) {
> // check the coordinates because Swarm does not
> // provide a toroidal space
> testCellX = xnorm(testX);
> testCellY = ynorm(testY);
> 
> // If there is no bug at this location, put the cell
> // at the location on the neighbor list.
> if (myBugWorld.getObjectAtX$Y(testCellX, testCellY) == null)
> neighborCellList.addLast(myCellWorld.getObjectAtX$Y(testCellX, 
> testCellY));
> }
> }
> // If no vacant neighbor cells were found, the new bug dies
> if (neighborCellList.getCount() == 0) {
> modelSwarm.remove(this);
> return;
> }
> // Else the new bug moves to a randomly chosen vacant cell
> else {
> newCell = (HabitatCell) neighborCellList.atOffset
> (Globals.env.uniformIntRand.getIntegerWithMin$withMax
> (0, neighborCellList.getCount()-1));
> 
> myX = newCell.getMyX();
> myY = newCell.getMyY();
> myBugWorld.putObject$atX$Y(this, myX, myY);
> // the new bug gets put on the bug list in 'grow'
> }
> return;
> }
> 
> 
> -- 
> Lang Railsback & Associates
> 250 California Ave.
> Arcata CA  95521
> (707) 822-0453
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