GSL复数快速傅里叶变换FFT

#include <stdio.h>#include <math.h>#include <gsl/gsl_errno.h>#include <gsl/gsl_fft_complex.h>#pragma comment(lib, "libgsl_d.lib")#pragma comment(lib, "libgslcblas_d.lib")#define REAL(z,i) ((z)[2*(i)])#define IMAG(z,i) ((z)[2*(i)+1])intmain (void){  int i;  const int n = 630;//   double data[2*n];  double data[2*630];  gsl_fft_complex_wavetable * wavetable;  gsl_fft_complex_workspace * workspace;  for (i = 0; i < n; i++)    {      REAL(data,i) = 0.0;      IMAG(data,i) = 0.0;    }  data[0] = 1.0;  for (i = 1; i <= 10; i++)    {      REAL(data,i) = REAL(data,n-i) = 1.0;    }  for (i = 0; i < n; i++)    {      printf ("%d: %e %e\n", i, REAL(data,i),                                 IMAG(data,i));    }  printf ("\n");  wavetable = gsl_fft_complex_wavetable_alloc (n);  workspace = gsl_fft_complex_workspace_alloc (n);  for (i = 0; i < wavetable->nf; i++)    {       printf ("# factor %d: %d\n", i,                wavetable->factor[i]);    }  gsl_fft_complex_forward (data, 1, n,                            wavetable, workspace);  for (i = 0; i < n; i++)    {      printf ("%d: %e %e\n", i, REAL(data,i),                                 IMAG(data,i));    }  gsl_fft_complex_wavetable_free (wavetable);  gsl_fft_complex_workspace_free (workspace);  return 0;}