rendered paste body/*
* r = radius = 1
* A_Circle = r^2 * Pi = r * r
* A_Square = (2*r)^2 = 4 * r * r
* X_C_S = A_Circle / A_Square
* Y_C_S = InCircleCount / SampleCount
* X_C_Y = Y_C_S
* InCircleCount / SampleCount = Pi * 1/4 <=>
* Pi = 4 * InCircleCount / SampleCount
*/
public class Pi {
private static double THRESHOLD=0.000001f;
private static double root(double x){
if(x < 0) return -1.0f;
double t0,t1;
t0=1.0f;
do{
t1=t0;
t0=(t1 + x/t1)/2.0f;
}while(Math.abs(t0 - t1) >= THRESHOLD);
return t0;
}
private static float calc(int steps){
int c = 0;
double x,y;
for(int i = 0; i<steps; i++){
x = Math.random();
y = Math.random();
if(root(x * x + y * y) <= 1){
c++;
}
}
return 4.0f * c / steps;
}
public static void main(String args[]){
System.out.print("Pi = " + calc(1000000));
}
}