Roulette-wheel selection via stochastic acceptance. More on http://arxiv.org/abs/1109.3627 https://en.wikipedia.org/wiki/Fitness_proportionate_selection

roulette.java

public class roulette {
  public static void main(String [] args) {
  	int n=4;
  	double [] weight = new double [n];
  	weight[0]=0.4;
  	weight[1]=0.3;
  	weight[2]=1.2;
  	weight[3]=0.1;
  	double max_weight=1.2;
  	int  [] counter = new int[n];
  	int n_select=1000;
  	int index=0;
  	boolean notaccepted;
  	for (int i=0; i<n_select; i++){
  		notaccepted=true;
  		while (notaccepted){
  			index= (int)(n*Math.random());
  			if(Math.random()<weight[index]/max_weight) {notaccepted=false;}
  		}
  		counter[index]++;
  	}
  	for (int i=0; i<n; i++){
  		System.out.println("counter["+i+"]="+counter[i]);
  	}
  }
}