快速傅立叶的两种实现方法,c#

两种FFT（快速傅里叶变换的算法）c#  
     
//迭代法求FFT
//DataIn_r, DataIn_i为输入的复数实部与需步,DataOut_r,DataOut_i为输出的实部与需部
        private void FFT1(ref double[] DataIn_r, ref double[] DataIn_i, ref double[] DataOut_r, ref double[] DataOut_i)

        {

            int len = DataIn_r.Length;

            if (len == 1)

            {

                DataOut_r = DataIn_r;

                DataOut_i = DataIn_i;

                return;

            }

            len = len / 2;

            //

            double[] evenData_r = new double[len];

            double[] evenData_i = new double[len];

            double[] oddData_r = new double[len];

            double[] oddData_i = new double[len];

            //

            double[] evenResult_r = new double[len];

            double[] evenResult_i = new double[len];

            double[] oddResult_r = new double[len];

            double[] oddResult_i = new double[len];

            //

            for (int i = 0; i < len; i++)

            {

                evenData_r[i] = DataIn_r[i * 2];

                evenData_i[i] = DataIn_i[i * 2];

                oddData_r[i] = DataIn_r[i * 2 + 1];

                oddData_i[i] = DataIn_i[i * 2 + 1];

            }