Accord.Math.Wavelets.Haar.FWT C# (CSharp) Method

        public static void FWT(double[] data)
        {
            double[] temp = new double[data.Length];

            int h = data.Length >> 1;
            for (int i = 0; i < h; i++)
            {
                int k = (i << 1);
                temp[i] = data[k] * s0 + data[k + 1] * s1;
                temp[i + h] = data[k] * w0 + data[k + 1] * w1;
            }

            for (int i = 0; i < data.Length; i++)
                data[i] = temp[i];
        }