Gaussian

    /* Random number with Gaussian distribution.
    
    Translated from Python's library random module to C#
    by Russell Borogove.
    */
    
    const double NO_VALUE = -1e6f;
    const double TAU = Math.PI*2.0;
    static double gaussNext = NO_VALUE;
    public static double Gaussian( double mu, double sigma )
    {
        /*
        mu is the mean, and sigma is the standard deviation.  This is
        slightly faster than the normalvariate() function.

        # When x and y are two variables from [0, 1), uniformly
        # distributed, then
        #
        #    cos(2*pi*x)*sqrt(-2*log(1-y))
        #    sin(2*pi*x)*sqrt(-2*log(1-y))
        #
        # are two *independent* variables with normal distribution
        # (mu = 0, sigma = 1).
        # (Lambert Meertens)
        # (corrected version; bug discovered by Mike Miller, fixed by LM)
        */

        double z = gaussNext;
        gaussNext = NO_VALUE;

        if (z == NO_VALUE)
        {
            double x2pi = UnityEngine.Random.value * TAU;
            double g2rad = Math.Sqrt(-2.0 * Math.Log(1.0 - UnityEngine.Random.value));
            z = Math.Cos(x2pi) * g2rad;
            gaussNext = Math.Sin(x2pi) * g2rad;
        }

        return mu + z*sigma;
    }