kissfft/test/test_real.c
2003-12-15 03:23:46 +00:00

119 lines
2.9 KiB
C

#include "kiss_fftr.h"
#include "_kiss_fft_guts.h"
#include <sys/times.h>
#include <time.h>
#include <unistd.h>
static double cputime()
{
struct tms t;
times(&t);
return (double)(t.tms_utime + t.tms_stime)/ sysconf(_SC_CLK_TCK) ;
}
double snr_compare( kiss_fft_cpx * vec1,kiss_fft_cpx * vec2, int n)
{
int k;
double sigpow,noisepow,err,snr,scale=0;
sigpow = noisepow = .00000000000000000001;
for (k=0;k<n;++k) {
sigpow += (double)vec1[k].r * (double)vec1[k].r +
(double)vec1[k].i * (double)vec1[k].i;
err = (double)vec1[k].r - (double)vec2[k].r;
noisepow += err * err;
err = (double)vec1[k].i - (double)vec2[k].i;
noisepow += err * err;
if (vec1[k].r)
scale +=(double) vec2[k].r / (double)vec1[k].r;
/*
fprintf(stderr,"vec1=");pcpx(vec1+k);
fprintf(stderr,"vec2=");pcpx(vec2+k);
*/
}
snr = 10*log10( sigpow / noisepow );
scale /= n;
if (snr<10)
printf( "\npoor snr, try a scaling factor %f\n" , scale );
return snr;
}
#define RANDOM
#ifndef RANDOM
#define NFFT 8
#else
#define NFFT 8*3*5
#endif
#ifndef NUMFFTS
#define NUMFFTS 1000
#endif
int main()
{
double ts,tfft,trfft;
int i;
kiss_fft_cpx cin[NFFT];
kiss_fft_scalar sin[NFFT] = {0.309655,0.815653,0.768570,0.591841,0.404767,0.637617,0.007803,0.012665};
kiss_fft_cpx cout[NFFT];
kiss_fft_cpx sout[NFFT];
void * kiss_fft_state;
void * kiss_fftr_state;
srand(time(0));
for (i=0;i<NFFT;++i) {
#ifdef RANDOM
sin[i] = (kiss_fft_scalar)(rand()-RAND_MAX/2);
#endif
cin[i].r = sin[i];
cin[i].i = 0;
}
kiss_fft_state = kiss_fft_alloc(NFFT,0,0,0);
kiss_fftr_state = kiss_fftr_alloc(NFFT,0,0,0);
kiss_fft(kiss_fft_state,cin,cout);
kiss_fftr(kiss_fftr_state,sin,sout);
printf( "nfft=%d, inverse=%d, snr=%g\n",
NFFT,0, snr_compare(cout,sout,(NFFT/2)+1) );
#ifdef RANDOM
ts = cputime();
for (i=0;i<NUMFFTS;++i) {
kiss_fft(kiss_fft_state,cin,cout);
}
tfft = cputime() - ts;
ts = cputime();
for (i=0;i<NUMFFTS;++i) {
kiss_fftr( kiss_fftr_state, sin, cout );
/* kiss_fftri(kiss_fftr_state,cout,sin); */
}
trfft = cputime() - ts;
printf("%d complex ffts took %gs, real took %gs\n",NUMFFTS,tfft,trfft);
#endif
free(kiss_fft_state);
free(kiss_fftr_state);
kiss_fft_state = kiss_fft_alloc(NFFT,1,0,0);
kiss_fftr_state = kiss_fftr_alloc(NFFT,1,0,0);
kiss_fft(kiss_fft_state,cout,cin);
kiss_fftri(kiss_fftr_state,cout,sin);
for (i=0;i<NFFT;++i) {
sout[i].r = sin[i];
sout[i].i = 0;
}
printf( "nfft=%d, inverse=%d, snr=%g\n",
NFFT,1, snr_compare(cin,cin,NFFT/2) );
free(kiss_fft_state);
free(kiss_fftr_state);
return 0;
}