Accord.Math.Special.Log1m C# (CSharp) Method

        public static double Log1m(double x)
        {
            if (x >= 1.0)
                return Double.NaN;

            if (Math.Abs(x) > 1e-4)
                return Math.Log(1.0 - x);

            // Use Taylor approx. log(1 + x) = x - x^2/2 with error roughly x^3/3
            // Since |x| < 10^-4, |x|^3 < 10^-12, relative error less than 10^-8
            return -(0.5 * x + 1.0) * x;
        }