virusinfectiondemo.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.virus;

import sim.field.continuous.*;
import sim.engine.*;
import sim.util.*;
import ec.util.*;
import java.io.*;


public /*strictfp*/ class VirusInfectionDemo extends SimState
    {
    public static final double XMIN = 0;
    public static final double XMAX = 800;
    public static final double YMIN = 0;
    public static final double YMAX = 600;

    public static final double DIAMETER = 8;

    public static final double HEALING_DISTANCE = 20;
    public static final double HEALING_DISTANCE_SQUARED = HEALING_DISTANCE * HEALING_DISTANCE;
    public static final double INFECTION_DISTANCE = 20;
    public static final double INFECTION_DISTANCE_SQUARED = INFECTION_DISTANCE * INFECTION_DISTANCE;
    
    public static final int NUM_HUMANS = 100;
    public static final int NUM_GOODS = 4;
    public static final int NUM_EVILS = 4;

    public Continuous2D environment = null;

    /** Creates a VirusInfectionDemo simulation with the given random number seed. */
    public VirusInfectionDemo(long seed)
        {
        super(new MersenneTwisterFast(seed), new Schedule(2));
        }

    boolean conflict( final Agent agent1, final Double2D a, final Agent agent2, final Double2D b )
        {
        if( ( ( a.x > b.x && a.x < b.x+DIAMETER ) ||
              ( a.x+DIAMETER > b.x && a.x+DIAMETER < b.x+DIAMETER ) ) &&
            ( ( a.y > b.y && a.y < b.y+DIAMETER ) ||
              ( a.y+DIAMETER > b.y && a.y+DIAMETER < b.y+DIAMETER ) ) )
            {
            return true;
            }
        return false;
        }

    public boolean withinInfectionDistance( final Agent agent1, final Double2D a, final Agent agent2, final Double2D b )
        {
        return ( (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y) <= INFECTION_DISTANCE_SQUARED );
        }

    public boolean withinHealingDistance( final Agent agent1, final Double2D a, final Agent agent2, final Double2D b )
        {
        return ( (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y) <= HEALING_DISTANCE_SQUARED );
        }

    boolean acceptablePosition( final Agent agent, final Double2D location )
        {
        if( location.x < DIAMETER/2 || location.x > (XMAX-XMIN)/*environment.getXSize()*/-DIAMETER/2 ||
            location.y < DIAMETER/2 || location.y > (YMAX-YMIN)/*environment.getYSize()*/-DIAMETER/2 )
            return false;
        Bag mysteriousObjects = environment.getObjectsWithinDistance( location, 2*DIAMETER );
        if( mysteriousObjects != null )
            {
            for( int i = 0 ; i < mysteriousObjects.numObjs ; i++ )
                {
                if( mysteriousObjects.objs[i] != null && mysteriousObjects.objs[i] != agent )
                    {
                    Agent ta = (Agent)(mysteriousObjects.objs[i]);
                    if( conflict( agent, location, ta, environment.getObjectLocation(ta) ) )
                        return false;
                    }
                }
            }
        return true;
        }

    public void start()
        {
        super.start();  // clear out the schedule

        environment = new Continuous2D(25.0, (XMAX-XMIN), (YMAX-YMIN) );

        // Schedule the agents -- we could instead use a RandomSequence, which would be faster,
        // but this is a good test of the scheduler
        for(int x=0;x<NUM_HUMANS+NUM_GOODS+NUM_EVILS;x++)
            {
            Double2D loc = null;
            Int2D pos = null;
            Agent agent = null;
            int times = 0;
            do
                {
                loc = new Double2D( random.nextDouble()*(XMAX-XMIN-DIAMETER)+XMIN+DIAMETER/2,
                                    random.nextDouble()*(YMAX-YMIN-DIAMETER)+YMIN+DIAMETER/2 );
                if( x < NUM_HUMANS )
                    agent = new Human( "Human"+x, loc );
                else if( x < NUM_HUMANS+NUM_GOODS )
                    agent = new Good( "Good"+(x-NUM_HUMANS), loc );
                else
                    agent = new Evil( "Evil"+(x-NUM_HUMANS-NUM_GOODS), loc );
                times++;
                if( times == 1000 )
                    {
                    System.out.println( "Cannot place agents. Exiting...." );
                    System.exit(1);
                    }
                } while( !acceptablePosition( agent, loc ) );
            environment.setObjectLocation(agent,loc);
            schedule.scheduleRepeating(agent);
            }
        }

    public static void main(String[] args)
        {
        doLoop(VirusInfectionDemo.class, args);
        System.exit(0);
        }    
    }