Accord.Statistics.Kernels.Bessel.Function C# (CSharp) Method

        public override double Function(double[] x, double[] y)
        {
            double norm = 0.0;

            for (int k = 0; k < x.Length; k++)
            {
                double d = x[k] - y[k];
                norm += d * d;
            }

            norm = System.Math.Sqrt(norm);

            double num = Accord.Math.Bessel.J(order, sigma * norm);
            double den = System.Math.Pow(norm, -norm * order);

            return num / den;
        }