Option Pricing - Black Scholes en Java

public static double callPrice(double s, double x, double r, double q, double sigma, double t) {

double d1 = (Math.log(s/x) + (r-q + sigma * sigma/2) * t) / (sigma * Math.sqrt(t));

double d2 = d1 - sigma * Math.sqrt(t);

return s *Math.exp(-q*t) * Gaussian.cdf(d1) - x * Math.exp(-r*t) * Gaussian.cdf(d2);

}

public static void main(String[] args) {

double s = 100.0;

double x = 100.0;

double r = 0.0;

double q = 0.0;

double sigma = 0.3;

double t = 1.0;

System.out.println("call = "+ callPrice(s, x, r, q, sigma, t));

System.out.println("put = "+-callPrice(s, x, r, q, -sigma, t));

}