6211c90def
"inverse" flag from the state so it can be shared between the forward and inverse transforms.
86 lines
1.9 KiB
C
86 lines
1.9 KiB
C
#include <stdio.h>
|
|
#include "kiss_fft.h"
|
|
|
|
|
|
void check(kiss_fft_cpx * in,kiss_fft_cpx * out,int nfft,int isinverse)
|
|
{
|
|
int bin,k;
|
|
double errpow=0,sigpow=0;
|
|
|
|
for (bin=0;bin<nfft;++bin) {
|
|
double ansr = 0;
|
|
double ansi = 0;
|
|
double difr;
|
|
double difi;
|
|
|
|
for (k=0;k<nfft;++k) {
|
|
double phase = -2*M_PI*bin*k/nfft;
|
|
double re = cos(phase);
|
|
double im = sin(phase);
|
|
if (isinverse)
|
|
im = -im;
|
|
|
|
#ifdef FIXED_POINT
|
|
re /= nfft;
|
|
im /= nfft;
|
|
#endif
|
|
|
|
ansr += in[k].r * re - in[k].i * im;
|
|
ansi += in[k].r * im + in[k].i * re;
|
|
}
|
|
difr = ansr - out[bin].r;
|
|
difi = ansi - out[bin].i;
|
|
errpow += difr*difr + difi*difi;
|
|
sigpow += ansr*ansr+ansi*ansi;
|
|
}
|
|
printf("nfft=%d inverse=%d,snr = %f\n",nfft,isinverse,10*log10(sigpow/errpow) );
|
|
}
|
|
|
|
void test1d(int nfft,int isinverse)
|
|
{
|
|
size_t buflen = sizeof(kiss_fft_cpx)*nfft;
|
|
|
|
kiss_fft_cpx * in = (kiss_fft_cpx*)malloc(buflen);
|
|
kiss_fft_cpx * out= (kiss_fft_cpx*)malloc(buflen);
|
|
kiss_fft_cfg cfg = kiss_fft_alloc(nfft,0,0);
|
|
int k;
|
|
|
|
for (k=0;k<nfft;++k) {
|
|
in[k].r = (rand() % 65536) - 32768;
|
|
in[k].i = (rand() % 65536) - 32768;
|
|
}
|
|
|
|
if (isinverse)
|
|
kiss_ifft(cfg,in,out);
|
|
else
|
|
kiss_fft(cfg,in,out);
|
|
|
|
check(in,out,nfft,isinverse);
|
|
|
|
free(in);
|
|
free(out);
|
|
free(cfg);
|
|
}
|
|
|
|
int main(int argc,char ** argv)
|
|
{
|
|
if (argc>1) {
|
|
int k;
|
|
for (k=1;k<argc;++k) {
|
|
test1d(atoi(argv[k]),0);
|
|
test1d(atoi(argv[k]),1);
|
|
}
|
|
}else{
|
|
test1d(32,0);
|
|
test1d(32,1);
|
|
test1d(36,0);
|
|
test1d(36,1);
|
|
test1d(50,0);
|
|
test1d(50,1);
|
|
test1d(120,0);
|
|
test1d(120,1);
|
|
test1d(105,0);
|
|
test1d(105,1);
|
|
}
|
|
return 0;
|
|
}
|