SimpleATBot

package ntc;
import robocode.*;
import robocode.util.Utils;
import java.util.*;
import java.awt.geom.*;

/**
 * SimpleATBot - a robot by Starrynte
 * Demonstrates AreaTargeting with a simple MinimumRiskMovement

 * Changes
 * 0.1
 *     Created!
 *     
 */
public class SimpleATBot extends AdvancedRobot
{
	static Hashtable enemies=new Hashtable();
	static double segment;
	static Point2D.Double lastPosition,myPos,nextDestination;
	
	public void run() {
		setTurnRadarRightRadians(Double.POSITIVE_INFINITY);
		segment=(Math.PI*2)/(getOthers()*3);
		lastPosition=myPos=nextDestination=new Point2D.Double(getX(),getY());
		do{
			if(getTime()>10){
				move();
				gun();
			}
			segment=(Math.PI*2)/(getOthers()*3);
			myPos.setLocation(getX(),getY());
			execute();
		}while(true);
	}

	public void onScannedRobot(ScannedRobotEvent e) {
		Enemy en=(Enemy)enemies.get(e.getName());
		if(en==null){
			en=new Enemy();
			enemies.put(e.getName(),en);
		}
		en.live=true;
		en.energy=e.getEnergy();
		en.pos=projectPoint(myPos,e.getBearingRadians()+getHeadingRadians(),e.getDistance());		
	}
	
	public boolean move(){		
		for(int i=0;i<100;i++){
			Point2D.Double testPoint=projectPoint(myPos,Math.random()*2*Math.PI,50+Math.random()*150);
			if(evaluate(testPoint)<evaluate(nextDestination)){
				nextDestination=testPoint;
			}
		}
		lastPosition=myPos;
		driveTo(nextDestination);
		return true;
	}

	public boolean gun(){
		int[] botsInArea=new int[(int)segment];
		Enumeration e=enemies.elements();
		int curSegment=0;
		while(e.hasMoreElements()){
			Enemy en=(Enemy)e.nextElement();
			if(en.live){
				double ang=calcAngle(myPos,en.pos);			
				botsInArea[(int)(Math.abs(Math.floor(ang/segment)))]++;
			}
		}
		for(int i=0;i<(int)segment;i++){
			int bots=botsInArea[i];
			int curBots=botsInArea[curSegment];
			if(bots>curBots){
				curSegment=i;
			}
		}
		out.println("Using segment " + (curSegment*segment) + "~" + ((curSegment*segment)+segment));
		setTurnGunRightRadians(Utils.normalRelativeAngle(((curSegment*segment)+Math.random()*segment)-getGunHeadingRadians()));
		setFire(2);
		return true;
	}
	
	private double evaluate(Point2D.Double p){
		double risk=(1/lastPosition.distanceSq(p)) + (0.5/myPos.distanceSq(p));
		Enumeration e=enemies.elements();
		while(e.hasMoreElements()){
			Enemy en=(Enemy)e.nextElement();
			double thisRisk=en.energy/en.pos.distanceSq(p);
			if(en.live){
				risk+=thisRisk;
			}
		}
		return risk;
	}
	
	private double calcAngle(Point2D.Double s,Point2D.Double t){
		return Math.atan2(t.getX()-s.getX(),t.getY()-s.getY());
	}

	private Point2D.Double projectPoint(Point2D.Double s, double ang, double dist){
		return new Point2D.Double(s.getX()+(Math.sin(ang)*dist),
				s.getY()+(Math.cos(ang)*dist));
	}

	private void driveTo(Point2D.Double next){
		driveTo(next.getX(),next.getY());
	}

	private void driveTo(double nextX, double nextY){
		double myX = getX();double myY = getY();double turnAngle;double normalizedTurnAngle;
		setTurnRightRadians(normalizedTurnAngle =  Math.atan(Math.tan(turnAngle = ((Math.atan2(nextX - myX, nextY - myY) - getHeadingRadians()) + (7.0 *  Math.PI)) % (2.0 * Math.PI) -  Math.PI)));
		setAhead((normalizedTurnAngle == turnAngle ? 1.0 : -1.0) * (java.awt.geom.Point2D.Double.distance(myX, myY, nextX, nextY)));
	}

	class Enemy{
		boolean live;
		double energy;
		Point2D.Double pos;
	}
}

When I run the bot, I get an

Exception: java.lang.ArrayIndexOutOfBoundsException: 3 >= 0
java.lang.ArrayIndexOutOfBoundsException: 3 >= 0
    at java.util.Vector.elementAt(Vector.java:432)
    at ntc.SimpleATBot.gun(SimpleATBot.java:65)
    at ntc.SimpleATBot.run(SimpleATBot.java:28)
    at robocode.peer.RobotPeer.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:595)

Help? --Starrynte

A Vector comes empty, so on line 65 you're trying to fetch the 4th value (index 3) from a Vector with 0 values (3 >= 0). I suggest skipping the vectory and using an array (int[] botsInArea? = new int[numSegments]).

Hm...I didin't know you could initialize an array with a variable...but i'll try it. Thnx --Starrynte

Ok, changed the code a bit, but now I get an

Exception: java.lang.ArrayIndexOutOfBoundsException: 8
java.lang.ArrayIndexOutOfBoundsException: 8
    at ntc.SimpleATBot.gun(SimpleATBot.java:68)
    at ntc.SimpleATBot.run(SimpleATBot.java:29)
    at robocode.peer.RobotPeer.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:595)

It might be a problem with the hashtable, calcAngle(), or projectPoint(), since those are some functions (and variable) called by SimpleATBot (both directly and indirectly) --Starrynte

Ok, ArrayIndexOutOfBoundsException? fixed now (now I just have to tweak the movement a bit...and the gun! It always uses the 'due north' segment as the area) --Starrynte