AForge.Math.FourierTransform.DFT C# (CSharp) Method

        public static void DFT(Complex[] data, Direction direction)
        {
            int n = data.Length;
            double arg, cos, sin;
            var dst = new Complex[n];

            // for each destination element
            for (int i = 0; i < n; i++)
            {
                dst[i] = Complex.Zero;

                arg = -(int) direction*2.0*System.Math.PI*i/n;

                // sum source elements
                for (int j = 0; j < n; j++)
                {
                    cos = System.Math.Cos(j*arg);
                    sin = System.Math.Sin(j*arg);

                    dst[i].Re += (data[j].Re*cos - data[j].Im*sin);
                    dst[i].Im += (data[j].Re*sin + data[j].Im*cos);
                }
            }

            // copy elements
            if (direction == Direction.Forward)
            {
                // devide also for forward transform
                for (int i = 0; i < n; i++)
                {
                    data[i].Re = dst[i].Re/n;
                    data[i].Im = dst[i].Im/n;
                }
            }
            else
            {
                for (int i = 0; i < n; i++)
                {
                    data[i].Re = dst[i].Re;
                    data[i].Im = dst[i].Im;
                }
            }
        }