Chris@366: #include "kiss_fft.h"
Chris@366: 
Chris@366: 
Chris@366: void check(kiss_fft_cpx  * in,kiss_fft_cpx  * out,int nfft,int isinverse)
Chris@366: {
Chris@366:     int bin,k;
Chris@366:     double errpow=0,sigpow=0;
Chris@366:     
Chris@366:     for (bin=0;bin<nfft;++bin) {
Chris@366:         double ansr = 0;
Chris@366:         double ansi = 0;
Chris@366:         double difr;
Chris@366:         double difi;
Chris@366: 
Chris@366:         for (k=0;k<nfft;++k) {
Chris@366:             double phase = -2*M_PI*bin*k/nfft;
Chris@366:             double re = cos(phase);
Chris@366:             double im = sin(phase);
Chris@366:             if (isinverse)
Chris@366:                 im = -im;
Chris@366: 
Chris@366: #ifdef FIXED_POINT
Chris@366:             re /= nfft;
Chris@366:             im /= nfft;
Chris@366: #endif            
Chris@366: 
Chris@366:             ansr += in[k].r * re - in[k].i * im;
Chris@366:             ansi += in[k].r * im + in[k].i * re;
Chris@366:         }
Chris@366:         difr = ansr - out[bin].r;
Chris@366:         difi = ansi - out[bin].i;
Chris@366:         errpow += difr*difr + difi*difi;
Chris@366:         sigpow += ansr*ansr+ansi*ansi;
Chris@366:     }
Chris@366:     printf("nfft=%d inverse=%d,snr = %f\n",nfft,isinverse,10*log10(sigpow/errpow) );
Chris@366: }
Chris@366: 
Chris@366: void test1d(int nfft,int isinverse)
Chris@366: {
Chris@366:     size_t buflen = sizeof(kiss_fft_cpx)*nfft;
Chris@366: 
Chris@366:     kiss_fft_cpx  * in = (kiss_fft_cpx*)malloc(buflen);
Chris@366:     kiss_fft_cpx  * out= (kiss_fft_cpx*)malloc(buflen);
Chris@366:     kiss_fft_cfg  cfg = kiss_fft_alloc(nfft,isinverse,0,0);
Chris@366:     int k;
Chris@366: 
Chris@366:     for (k=0;k<nfft;++k) {
Chris@366:         in[k].r = (rand() % 65536) - 32768;
Chris@366:         in[k].i = (rand() % 65536) - 32768;
Chris@366:     }
Chris@366: 
Chris@366:     kiss_fft(cfg,in,out);
Chris@366: 
Chris@366:     check(in,out,nfft,isinverse);
Chris@366: 
Chris@366:     free(in);
Chris@366:     free(out);
Chris@366:     free(cfg);
Chris@366: }
Chris@366: 
Chris@366: int main(int argc,char ** argv)
Chris@366: {
Chris@366:     if (argc>1) {
Chris@366:         int k;
Chris@366:         for (k=1;k<argc;++k) {
Chris@366:             test1d(atoi(argv[k]),0);
Chris@366:             test1d(atoi(argv[k]),1);
Chris@366:         }
Chris@366:     }else{
Chris@366:         test1d(32,0);
Chris@366:         test1d(32,1);
Chris@366:     }
Chris@366:     return 0;
Chris@366: }