Accord.Tests.Math.BoundedBroydenFletcherGoldfarbShannoTest.rosenbrockGradient C# (CSharp) Method

        public static double[] rosenbrockGradient(double[] x)
        {
            double a = x[1] - x[0] * x[0];
            double b = 1 - x[0];

            double f0 = -2 * b - 400 * x[0] * a;
            double f1 = 200 * a;

            return new[] { f0, f1 };
        }