A RePast Tutorial by John T. Murphy, University of Arizona & Arizona State University (contact)

Reporting

A common and useful tactic, although not germane to the model, is to provide reporting functions. Some useful techniques for doing this include:

  1. Providing a 'report' function that lists the values of the instance variables for a given object
  2. Providing a unique 'ID' variable for each instance of an object

To achieve the second effect and have each agent have an ID number we will make use of static variables. We create a static variable that can be read by all instances of the class, and have the constructor increment it as a counter each time an agent is created.

We will also provide a 'get ID' method that will return the agent's unique ID, and get methods for 'money' and 'StepsToLive'- these will be useful when we look at gathering statistics anyway, over and above their use in the 'report' function:

We make use of the report function by adding a segment in the buildModel routine that runs through the list of all agents and asks them to report.

CarryDropModel

// CarryDropModel
package demo;

import java.awt.Color;
import java.util.ArrayList;

import uchicago.src.sim.engine.Schedule;
import uchicago.src.sim.engine.SimInit;
import uchicago.src.sim.engine.SimModelImpl;
import uchicago.src.sim.gui.DisplaySurface;
import uchicago.src.sim.gui.ColorMap;
import uchicago.src.sim.gui.Value2DDisplay;

public class CarryDropModel extends SimModelImpl {
  // Default Values
  private static final int NUMAGENTS = 100;
  private static final int WORLDXSIZE = 40;
  private static final int WORLDYSIZE = 40;
  private static final int TOTALMONEY = 1000;
  private static final int AGENT_MIN_LIFESPAN = 30;
  private static final int AGENT_MAX_LIFESPAN = 50;

  private int numAgents = NUMAGENTS;
  private int worldXSize = WORLDXSIZE;
  private int worldYSize = WORLDYSIZE;
  private int money = TOTALMONEY;
  private int agentMinLifespan = AGENT_MIN_LIFESPAN;
  private int agentMaxLifespan = AGENT_MAX_LIFESPAN;

  private Schedule schedule;

  private CarryDropSpace cdSpace;

  private ArrayList agentList;

  private DisplaySurface displaySurf;

  public String getName(){
    return "Carry And Drop";
  }

  public void setup(){
    System.out.println("Running setup");
    cdSpace = null;
    agentList = new ArrayList();

    if (displaySurf != null){
      displaySurf.dispose();
    }
    displaySurf = null;

    displaySurf = new DisplaySurface(this, "Carry Drop Model Window 1");

    registerDisplaySurface("Carry Drop Model Window 1", displaySurf);
  }

  public void begin(){
    buildModel();
    buildSchedule();
    buildDisplay();

    displaySurf.display();
  }

  public void buildModel(){
    System.out.println("Running BuildModel");
    cdSpace = new CarryDropSpace(worldXSize, worldYSize);
    cdSpace.spreadMoney(money);

    for(int i = 0; i < numAgents; i++){
      addNewAgent();
    }
    for(int i = 0; i < agentList.size(); i++){
      CarryDropAgent cda = (CarryDropAgent)agentList.get(i);
      cda.report();
    }
  }

  public void buildSchedule(){
    System.out.println("Running BuildSchedule");
  }

  public void buildDisplay(){
    System.out.println("Running BuildDisplay");

    ColorMap map = new ColorMap();

    for(int i = 1; i<16; i++){
      map.mapColor(i, new Color((int)(i * 8 + 127), 0, 0));
    }
    map.mapColor(0, Color.white);

    Value2DDisplay displayMoney =
        new Value2DDisplay(cdSpace.getCurrentMoneySpace(), map);

    displaySurf.addDisplayable(displayMoney, "Money");

  }

  private void addNewAgent(){
    CarryDropAgent a = new CarryDropAgent(agentMinLifespan, agentMaxLifespan);
    agentList.add(a);
    cdSpace.addAgent(a);
  }
  public Schedule getSchedule(){
    return schedule;
  }

  public String[] getInitParam(){
    String[] initParams = { "NumAgents", "WorldXSize", "WorldYSize", "Money", "AgentMinLifespan", "AgentMaxLifespan"};
    return initParams;
  }

  public int getNumAgents(){
    return numAgents;
  }

  public void setNumAgents(int na){
    numAgents = na;
  }

  public int getWorldXSize(){
    return worldXSize;
  }

  public void setWorldXSize(int wxs){
    worldXSize = wxs;
  }

  public int getWorldYSize(){
    return worldYSize;
  }

  public void setWorldYSize(int wys){
    worldYSize = wys;
  }

  public int getMoney() {
    return money;
  }

  public void setMoney(int i) {
    money = i;
  }

  public int getAgentMaxLifespan() {
    return agentMaxLifespan;
  }

  public int getAgentMinLifespan() {
    return agentMinLifespan;
  }

  public void setAgentMaxLifespan(int i) {
    agentMaxLifespan = i;
  }

  public void setAgentMinLifespan(int i) {
    agentMinLifespan = i;
  }

  public static void main(String[] args) {
    SimInit init = new SimInit();
    CarryDropModel model = new CarryDropModel();
    init.loadModel(model, "", false);
  }

}

CarryDropAgent

// CarryDropAgent
package demo;

public class CarryDropAgent {
  private int x;
  private int y;
  private int money;
  private int stepsToLive;
  private static int IDNumber = 0;
  private int ID;

  public CarryDropAgent(int minLifespan, int maxLifespan){
    x = -1;
    y = -1;
    money = 0;
    stepsToLive =
        (int)((Math.random() * (maxLifespan - minLifespan)) + minLifespan);
    IDNumber++;
    ID = IDNumber;
  }

  public void setXY(int newX, int newY){
    x = newX;
    y = newY;
  }

  public String getID(){
    return "A-" + ID;
  }

  public int getMoney(){
    return money;
  }

  public int getStepsToLive(){
    return stepsToLive;
  }

  public void report(){
    System.out.println(getID() +
                       " at " +
                       x + ", " + y +
                       " has " +
                       getMoney() + " dollars" +
                       " and " +
                       getStepsToLive() + " steps to live.");
  }

}

CarryDropSpace

// CarryDropSpace
package demo;

import uchicago.src.sim.space.Object2DGrid;


public class CarryDropSpace {
private Object2DGrid moneySpace;
private Object2DGrid agentSpace;

  public CarryDropSpace(int xSize, int ySize){
    moneySpace = new Object2DGrid(xSize, ySize);
    agentSpace = new Object2DGrid(xSize, ySize);

    for(int i = 0; i < xSize; i++){
      for(int j = 0; j < ySize; j++){
        moneySpace.putObjectAt(i,j,new Integer(0));
      }
    }
  }

  public void spreadMoney(int money){
    // Randomly place money in moneySpace
    for(int i = 0; i < money; i++){

      // Choose coordinates
      int x = (int)(Math.random()*(moneySpace.getSizeX()));
      int y = (int)(Math.random()*(moneySpace.getSizeY()));

      // Get the value of the object at those coordinates
      int currentValue = getMoneyAt(x, y);
      // Replace the Integer object with another one with the new value
      moneySpace.putObjectAt(x,y,new Integer(currentValue + 1));
    }
  }

  public int getMoneyAt(int x, int y){
    int i;
    if(moneySpace.getObjectAt(x,y)!= null){
      i = ((Integer)moneySpace.getObjectAt(x,y)).intValue();
    }
    else{
      i = 0;
    }
    return i;
  }

  public Object2DGrid getCurrentMoneySpace(){
    return moneySpace;
  }

  public boolean isCellOccupied(int x, int y){
    boolean retVal = false;
    if(agentSpace.getObjectAt(x, y)!=null) retVal = true;
    return retVal;
  }

  public boolean addAgent(CarryDropAgent agent){
    boolean retVal = false;
    int count = 0;
    int countLimit = 10 * agentSpace.getSizeX() * agentSpace.getSizeY();

    while((retVal==false) && (count < countLimit)){
      int x = (int)(Math.random()*(agentSpace.getSizeX()));
      int y = (int)(Math.random()*(agentSpace.getSizeY()));
      if(isCellOccupied(x,y) == false){
        agentSpace.putObjectAt(x,y,agent);
        agent.setXY(x,y);
        retVal = true;
      }
      count++;
    }

    return retVal;
  }

}

When this is run, the result should be a list of all agents and their relevant information.

Previous: Adding Agents to the space

Next: Displaying agents

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A RePast Tutorial by John T. Murphy, University of Arizona & Arizona State University (contact)