heatbugs.java

MASON代表多主体邻里或网络仿真(Multi-Agent Simulator of Neighborhoods or Networks)。它是乔治梅森大学用Java开发的离散事件多主体仿真核心库

package sim.app.heatbugs;
import sim.engine.*;
import sim.field.grid.*;
import sim.util.*;
import ec.util.*;
import java.io.*;

public /*strictfp*/ class HeatBugs extends SimState
    {
    public double minIdealTemp = 17000;
    public double maxIdealTemp = 31000;
    public double minOutputHeat = 6000;
    public double maxOutputHeat = 10000;

    public double evaporationRate = 0.993;
    public double diffusionRate = 1.0;
    public static final double MAX_HEAT = 32000;
    public double randomMovementProbability = 0.1;

    public int gridHeight;
    public int gridWidth;
    public int bugCount;
    HeatBug[] bugs;
    
    public double getMinimumIdealTemperature() { return minIdealTemp; }
    public void setMinimumIdealTemperature( double temp ) { if( temp <= maxIdealTemp ) minIdealTemp = temp; }
    public double getMaximumIdealTemperature() { return maxIdealTemp; }
    public void setMaximumIdealTemperature( double temp ) { if( temp >= minIdealTemp ) maxIdealTemp = temp; }
    public double getMinimumOutputHeat() { return minOutputHeat; }
    public void setMinimumOutputHeat( double temp ) { if( temp <= maxOutputHeat ) minOutputHeat = temp; }
    public double getMaximumOutputHeat() { return maxOutputHeat; }
    public void setMaximumOutputHeat( double temp ) { if( temp >= minOutputHeat ) maxOutputHeat = temp; }
    public double getEvaporationConstant() { return evaporationRate; }
    public void setEvaporationConstant( double temp ) { if( temp >= 0 && temp <= 1 ) evaporationRate = temp; }
    public Object domEvaporationConstant() { return new Interval(0.0,1.0); }
    public double getDiffusionConstant() { return diffusionRate; }
    public void setDiffusionConstant( double temp ) { if( temp >= 0 && temp <= 1 ) diffusionRate = temp; }
    public Object domDiffusionConstant() { return new Interval(0.0, 1.0); }
    public double getRandomMovementProbability() { return randomMovementProbability; }
    public void setRandomMovementProbability( double t )
        {
        if (t >= 0 && t <= 1)
            {
            randomMovementProbability = t;
            for( int i = 0 ; i < bugCount ; i++ )
                if (bugs[i]!=null)
                    bugs[i].setRandomMovementProbability( randomMovementProbability );
            }
        }
    public Object domRandomMovementProbability() { return new Interval(0.0, 1.0); }
        
    public double getMaximumHeat() { return MAX_HEAT; }

    // we presume that no one relies on these DURING a simulation
    public int getGridHeight() { return gridHeight; }
    public void setGridHeight(int val) { if (val > 0) gridHeight = val; }
    public int getGridWidth() { return gridWidth; }
    public void setGridWidth(int val) { if (val > 0) gridWidth = val; }
    public int getBugCount() { return bugCount; }
    public void setBugCount(int val) { if (val >= 0) bugCount = val; }
    
    public DoubleGrid2D valgrid;
    public DoubleGrid2D valgrid2;
    public SparseGrid2D buggrid;
    

    /** Creates a HeatBugs simulation with the given random number seed. */
    public HeatBugs(long seed)
        {
        this(seed, 100, 100, 100);
        }
        
    public HeatBugs(long seed, int width, int height, int count)
        {
        super(new MersenneTwisterFast(seed), new Schedule(2));
        gridWidth = width; gridHeight = height; bugCount = count;
        createGrids();
        }

    protected void createGrids()
        {
        bugs = new HeatBug[bugCount];
        valgrid = new DoubleGrid2D(gridWidth, gridHeight,0);
        valgrid2 = new DoubleGrid2D(gridWidth, gridHeight, 0);
        buggrid = new SparseGrid2D(gridWidth, gridHeight);      
        }
    
    /** Resets and starts a simulation */
    public void start()
        {
        super.start();  // clear out the schedule
        
        // make new grids
        createGrids();
    
        // Schedule the heat bugs -- we could instead use a RandomSequence, which would be faster
        // But we spend no more than 3% of our total runtime in the scheduler max, so it's not worthwhile
        for(int x=0;x<bugCount;x++)
            {
            bugs[x] = new HeatBug(random.nextDouble() * (maxIdealTemp - minIdealTemp) + minIdealTemp,
                                  random.nextDouble() * (maxOutputHeat - minOutputHeat) + minOutputHeat,
                                  randomMovementProbability);
            buggrid.setObjectLocation(bugs[x],random.nextInt(gridWidth),random.nextInt(gridHeight));
            schedule.scheduleRepeating(bugs[x]);
            }
                        
        // Here we're going to pick whether or not to use Diffuser (the default) or if
        // we're really going for the gusto and have multiple processors on our computer, we
        // can use our multithreaded super-neato ThreadedDiffuser!  On a Power Mac G5 with
        // two processors, we get almost a 90% speedup in the underlying model because *so*
        // much time is spent in the Diffuser.
                            
        // Schedule the diffuser to happen after the heatbugs
        if (availableProcessors() >  1)  // yay, multi-processor!
            schedule.scheduleRepeating(Schedule.EPOCH,1,new ThreadedDiffuser(),1);
        else
            schedule.scheduleRepeating(Schedule.EPOCH,1,new Diffuser(),1);
        }
    
    /** This little function calls Runtime.getRuntime().availableProcessors() if it's available,
        else returns 1.  That function is nonexistent in Java 1.3.1, but it exists in 1.4.x.
        So we're doing a little dance through the Reflection library to call the method tentatively!
        The value returned by Runtime is the number of available processors on the computer.  
        If you're only using 1.4.x, then all this is unnecessary -- you can just call
        Runtime.getRuntime().availableProcessors() instead. */
    public int availableProcessors()
        {
        Runtime runtime = Runtime.getRuntime();
        try { return ((Integer)runtime.getClass().getMethod("availableProcessors", null).
                      invoke(runtime,null)).intValue(); }
        catch (Exception e) { return 1; }  // a safe but sometimes wrong assumption!
        }
        
    
    
    public static void main(String[] args)
        {
        doLoop(HeatBugs.class, args);
        System.exit(0);
        }    
    }