[SOLVED] Double becomes infinity

Newbie & Debugging Questions
#1

Greetings,

I don’t know what to do to solve this. If anyone know what’s the problem, tell it to me in words. I am not learning if someone is pasting codes ^w^!
Tick

for (int i = 0; i < entities.size(); i++){
			if(entities.get(i) != sun){
				for (int j = 0; j < entities.size(); j++){
			        if (i != j){
			        	double dist = Math.sqrt(Math.exp(entities.get(i).getX() - entities.get(j).getX()) + Math.exp(entities.get(i).getY() - entities.get(j).getY()));
				        double accMag = entities.get(j).getMass()/(Math.exp(dist));
				        double accX = accMag*(entities.get(j).getX() - entities.get(j).getY())/dist;
				        double accY = accMag*(entities.get(j).getY() - entities.get(j).getY())/dist;
				        entities.get(i).addVX(accX);
				        entities.get(i).addVY(accY);
				        System.out.println("dist: " + dist + ", accMag: " + accMag + ", accX: " + accX + ", accY: " + accY);
			        }
				}
		        entities.get(i).updatePosition();	
		        System.out.println("New postition of Planet [x=" + entities.get(i).getX() + ", y=" + entities.get(i).getY() + "]");
			}
		}

System.out.println()

dist: Infinity, accMag: 0.0, accX: 0.0, accY: 0.0
New postition of Kerbin [x=80000.0, y=0.0]

Well the problem is basically as you can see, that dist is becomming Infinity, and because of this, the other variables are 0

-RoseSlayer

#2

I’m not sure about Java, but with other languages (like lua), if the number gets too big, it will become infinity…

But I don’t really know why that is happening in your code… It most likely has to do with Math.exp because Math.sqrt would definitely make it smaller…

#3

my guess is dist is actually zero and its squar-root is infinity.

what’s the exp of zero ?

#4

Step backward: Math.exp(x) = e^x. you want x*x.

exp of zero is one.

#5

yes, I want x^2. stupid of me …

#6

[icode]System.out.println(Math.exp(80000));[/icode]

[quote]Infinity
[/quote]
There’s your problem. e80000