mirror/kissfft
1
0
Fork 0
mirror of https://github.com/mborgerding/kissfft.git synced 2025-07-14 11:04:18 -04:00
Code Issues Packages Projects Releases Wiki Activity

real inverse fixed point fft scaling was broken. Now fixed is fixed.

Browse Source
This commit is contained in:
Mark Borgerding
2005-10-27 18:56:45 +00:00
parent 18d0ad1604
commit f088e415b4
2 changed files with 100 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files

85
test/test_real.c
View File

@ -11,6 +11,17 @@ static double cputime(void)
return (double)(t.tms_utime + t.tms_stime)/ sysconf(_SC_CLK_TCK) ;
}
static
kiss_fft_scalar rand_scalar(void)
{
#ifdef USE_SIMD
return _mm_set1_ps(rand()-RAND_MAX/2);
#else
kiss_fft_scalar s = (kiss_fft_scalar)(rand() -RAND_MAX/2);
return s/2;
#endif
}
static
double snr_compare( kiss_fft_cpx * vec1,kiss_fft_cpx * vec2, int n)
{
@ -65,25 +76,34 @@ int main(void)
kiss_fft_cfg kiss_fft_state;
kiss_fftr_cfg kiss_fftr_state;
kiss_fft_scalar rin[NFFT];
kiss_fft_scalar rin[NFFT+2];
kiss_fft_scalar rout[NFFT+2];
kiss_fft_scalar zero;
memset(&zero,0,sizeof(zero) ); // ugly way of setting short,int,float,double, or __m128 to zero
srand(time(0));
for (i=0;i<NFFT;++i) {
#ifdef USE_SIMD
rin[i] = _mm_set1_ps(rand()-RAND_MAX/2);
cin[i].i = _mm_set1_ps(0);
#else
rin[i] = (kiss_fft_scalar)(rand()-RAND_MAX/2);
cin[i].i = 0;
#endif
rin[i] = rand_scalar();
cin[i].r = rin[i];
cin[i].i = zero;
}
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,rin,sout);
/*
printf(" results from kiss_fft : (%f,%f), (%f,%f), (%f,%f) ...\n "
, (float)cout[0].r , (float)cout[0].i
, (float)cout[1].r , (float)cout[1].i
, (float)cout[2].r , (float)cout[2].i);
printf(" results from kiss_fftr: (%f,%f), (%f,%f), (%f,%f) ...\n "
, (float)sout[0].r , (float)sout[0].i
, (float)sout[1].r , (float)sout[1].i
, (float)sout[2].r , (float)sout[2].i);
*/
printf( "nfft=%d, inverse=%d, snr=%g\n",
NFFT,0, snr_compare(cout,sout,(NFFT/2)+1) );
ts = cputime();
@ -107,23 +127,44 @@ int main(void)
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,rin);
for (i=0;i<NFFT;++i) {
sout[i].r = rin[i];
#ifdef USE_SIMD
sout[i].i ^= sout[i].i;
#else
sout[i].i = 0;
#endif
memset(cin,0,sizeof(cin));
#if 1
for (i=1;i< NFFT/2;++i) {
//cin[i].r = (kiss_fft_scalar)(rand()-RAND_MAX/2);
cin[i].r = rand_scalar();
cin[i].i = rand_scalar();
}
#else
cin[0].r = 12000;
cin[3].r = 12000;
cin[NFFT/2].r = 12000;
#endif
// conjugate symmetry of real signal
for (i=1;i< NFFT/2;++i) {
cin[NFFT-i].r = cin[i].r;
cin[NFFT-i].i = - cin[i].i;
}
kiss_fft(kiss_fft_state,cin,cout);
kiss_fftri(kiss_fftr_state,cin,rout);
/*
printf(" results from inverse kiss_fft : (%f,%f), (%f,%f), (%f,%f), (%f,%f), (%f,%f) ...\n "
, (float)cout[0].r , (float)cout[0].i , (float)cout[1].r , (float)cout[1].i , (float)cout[2].r , (float)cout[2].i , (float)cout[3].r , (float)cout[3].i , (float)cout[4].r , (float)cout[4].i
);
printf(" results from inverse kiss_fftr: %f,%f,%f,%f,%f ... \n"
,(float)rout[0] ,(float)rout[1] ,(float)rout[2] ,(float)rout[3] ,(float)rout[4]);
*/
for (i=0;i<NFFT;++i) {
sout[i].r = rout[i];
sout[i].i = zero;
}
printf( "nfft=%d, inverse=%d, snr=%g\n",
NFFT,1, snr_compare(cin,cin,NFFT/2) );
NFFT,1, snr_compare(cout,sout,NFFT/2) );
free(kiss_fft_state);
free(kiss_fftr_state);
return 0;
}