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https://github.com/mborgerding/kissfft.git
synced 2025-05-27 21:20:27 -04:00
kiss_fftr.c gives correct answers for forward
This commit is contained in:
Mark Borgerding
parent
c2eaab8606
commit
09dbf36e97
3
fft.py
3
fft.py
@ -64,12 +64,15 @@ def real_fft( f,inv ):
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ims = f[1::2]
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fp = [ complex(r,i) for r,i in zip(res,ims) ]
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print 'fft input ', fp
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Fp = fft( fp ,0 )
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print 'fft output ', Fp
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F = []
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for k in range(N):
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F1k = Fp[k] + Fp[-k].conjugate()
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F2k = -j*(Fp[k] - Fp[-k].conjugate())
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print 'F2k[%d]=%s' % (k,F2k)
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F.append( ( F1k + e ** ( -j*pi*k/N ) * F2k ) * .5 )
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@ -11,10 +11,11 @@ ifeq "$(DATATYPE)" ""
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endif
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UTIL=fftutil_$(DATATYPE)
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TESTREAL=tr_$(DATATYPE)
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BENCHKISS=bm_kiss_$(DATATYPE)
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BENCHFFTW=bm_fftw_$(DATATYPE)
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all: $(UTIL) $(BENCHKISS)
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all: $(UTIL) $(BENCHKISS) $(TESTREAL)
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ifeq "$(DATATYPE)" "short"
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TYPEFLAGS=-DFIXED_POINT -Dkiss_fft_scalar=short
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@ -29,6 +30,9 @@ CFLAGS=-Wall -O3 -ansi -pedantic -march=pentiumpro -ffast-math -fomit-frame-poin
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$(UTIL): ../kiss_fft.c ../kiss_fft2d.c fftutil.c
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gcc -o $@ $(CFLAGS) -I.. $(TYPEFLAGS) ../kiss_fft.c ../kiss_fft2d.c fftutil.c -lm
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$(TESTREAL): ../kiss_fft.c ../kiss_fftr.c test_real.c
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gcc -o $@ $(CFLAGS) -I.. $(TYPEFLAGS) -lm $+
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$(BENCHKISS): benchkiss.c ../kiss_fft.c pstats.c
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gcc -o $@ $(CFLAGS) -I.. benchkiss.c $(TYPEFLAGS) ../kiss_fft.c pstats.c -lm
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@ -20,13 +20,23 @@ def c_format(v,round=0):
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s= ','.join( [ '{%.60f ,%.60f }' %(c.real,c.imag) for c in v ] )
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return re.sub(r'\.?0+ ',' ',s)
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def test_vec( n,inverse ):
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def test_cpx( n,inverse ,short):
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v = randvec(n,1)
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scale = 1
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if inverse:
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tvecout = FFT.inverse_fft(v)
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tvecout = [ c * len(v) for c in tvecout ]
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if short:
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scale = 1
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else:
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scale = len(v)
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else:
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tvecout = FFT.fft(v)
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if short:
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scale = 1.0/len(v)
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tvecout = [ c * scale for c in tvecout ]
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s="""#define NFFT %d""" % len(v) + """
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{
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@ -75,7 +85,13 @@ double snr_compare( kiss_fft_cpx * test_vec_out,kiss_fft_cpx * testbuf, int n)
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return s
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def main():
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fftsizes = sys.argv[1:]
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from getopt import getopt
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opts,args = getopt(sys.argv[1:],'s')
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opts = dict(opts)
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short = int( opts.has_key('-s') )
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fftsizes = args
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if not fftsizes:
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fftsizes = [ 1800 ]
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print '#include "kiss_fft.h"'
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@ -83,8 +99,8 @@ def main():
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print "int main() {"
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for n in fftsizes:
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n = int(n)
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print test_vec(n,0)
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print test_vec(n,1)
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print test_cpx(n,0,short)
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print test_cpx(n,1,short)
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print """
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return 0;
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}
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75
test/test_real.c
Normal file
75
test/test_real.c
Normal file
@ -0,0 +1,75 @@
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#include "kiss_fft.h"
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void * kiss_fftr_alloc(int nfft,int inverse_fft);
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void kiss_fftr(const void * cfg,const kiss_fft_scalar *fin,kiss_fft_cpx *fout);
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double snr_compare( kiss_fft_cpx * vec1,kiss_fft_cpx * vec2, int n)
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{
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int k;
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double sigpow,noisepow,err,snr,scale=0;
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sigpow = noisepow = .000000000000000000000000000001;
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for (k=0;k<n;++k) {
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sigpow += vec1[k].r * vec1[k].i +
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vec1[k].i * vec1[k].i;
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err = vec1[k].r - vec2[k].r;
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noisepow += err * err;
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err = vec1[k].i - vec2[k].i;
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noisepow += err * err;
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if (vec1[k].r)
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scale += vec2[k].r / vec1[k].r;
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}
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snr = 10*log10( sigpow / noisepow );
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scale /= n;
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if (snr<10)
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printf( "\npoor snr, try a scaling factor %f\n" , scale );
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return snr;
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}
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#define RANDOM
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#ifndef RANDOM
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#define NFFT 8
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#else
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#define NFFT 120
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#endif
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void pcpx(const char * msg, kiss_fft_cpx * c)
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{
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printf("%s: %g + %gi\n",msg,c->r,c->i);
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}
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int main()
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{
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int i;
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kiss_fft_cpx cin[NFFT];
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kiss_fft_scalar sin[NFFT] = {0.309655,0.815653,0.768570,0.591841,0.404767,0.637617,0.007803,0.012665};
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kiss_fft_cpx cout[NFFT];
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kiss_fft_cpx sout[NFFT];
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const void * kiss_fft_state;
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const void * kiss_fftr_state;
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int inverse = 0;
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kiss_fft_state = kiss_fft_alloc(NFFT,inverse);
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kiss_fftr_state = kiss_fftr_alloc(NFFT,inverse);
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for (i=0;i<NFFT;++i) {
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#ifdef RANDOM
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sin[i] = (kiss_fft_scalar)(rand()-RAND_MAX/2);
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#endif
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cin[i].r = sin[i];
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cin[i].i = 0;
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/* printf("in[%d]",i);pcpx("",cin+i); */
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}
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kiss_fft(kiss_fft_state,cin,cout);
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kiss_fftr(kiss_fftr_state,sin,sout);
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printf( "nfft=%d, inverse=%d, snr=%g\n",
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NFFT,inverse, snr_compare(cout,sout,NFFT/2) );
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return 0;
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}
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@ -11,10 +11,11 @@ ifeq "$(DATATYPE)" ""
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endif
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UTIL=fftutil_$(DATATYPE)
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TESTREAL=tr_$(DATATYPE)
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BENCHKISS=bm_kiss_$(DATATYPE)
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BENCHFFTW=bm_fftw_$(DATATYPE)
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all: $(UTIL) $(BENCHKISS)
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all: $(UTIL) $(BENCHKISS) $(TESTREAL)
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ifeq "$(DATATYPE)" "short"
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TYPEFLAGS=-DFIXED_POINT -Dkiss_fft_scalar=short
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@ -29,6 +30,9 @@ CFLAGS=-Wall -O3 -ansi -pedantic -march=pentiumpro -ffast-math -fomit-frame-poin
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$(UTIL): ../kiss_fft.c ../kiss_fft2d.c fftutil.c
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gcc -o $@ $(CFLAGS) -I.. $(TYPEFLAGS) ../kiss_fft.c ../kiss_fft2d.c fftutil.c -lm
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$(TESTREAL): ../kiss_fft.c ../kiss_fftr.c test_real.c
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gcc -o $@ $(CFLAGS) -I.. $(TYPEFLAGS) -lm $+
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$(BENCHKISS): benchkiss.c ../kiss_fft.c pstats.c
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gcc -o $@ $(CFLAGS) -I.. benchkiss.c $(TYPEFLAGS) ../kiss_fft.c pstats.c -lm
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