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https://github.com/mborgerding/kissfft.git
synced 2025-05-27 21:20:27 -04:00
re-added radix 3 butterfly
This commit is contained in:
Mark Borgerding
parent
ca4c74e07c
commit
d4f87befda
60
kiss_fft.c
60
kiss_fft.c
@ -59,6 +59,8 @@ typedef struct {
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# define C_FIXDIV(c,div) /* NOOP */
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#endif
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#define C_ADD( res, a,b)\
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do { (res).r=(a).r+(b).r; (res).i=(a).i+(b).i; }while(0)
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#define C_SUB( res, a,b)\
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do { (res).r=(a).r-(b).r; (res).i=(a).i-(b).i; }while(0)
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#define C_ADDTO( res , a)\
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@ -162,6 +164,59 @@ void bfly4(
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}while(--m);
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}
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void bfly3(
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kiss_fft_cpx * Fout,
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int fstride,
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const kiss_fft_state * st,
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int m
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)
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{
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kiss_fft_cpx *Fout0,*Fout1,*Fout2;
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kiss_fft_cpx *tw1,*tw2;
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kiss_fft_cpx * scratch = st->scratch;
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kiss_fft_cpx * twiddles = st->twiddles;
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kiss_fft_cpx epi3;
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epi3 = twiddles[fstride*m];
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Fout0=Fout;
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Fout1=Fout0+m;
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Fout2=Fout0+2*m;
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tw1=tw2=twiddles;
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do{
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C_FIXDIV(*Fout,3); C_FIXDIV(*Fout1,3); C_FIXDIV(*Fout2,3);
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scratch[0] = *Fout0;
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C_MUL(scratch[1],*Fout1 , *tw1);
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C_MUL(scratch[2],*Fout2 , *tw2);
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tw1 += fstride;
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tw2 += fstride*2;
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C_ADD(scratch[4],scratch[1],scratch[2]);
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C_ADD(*Fout0,scratch[0],scratch[4]);
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scratch[4].r /= -2;
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scratch[4].i /= -2;
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C_SUB(scratch[5],scratch[1],scratch[2]);
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scratch[5].r *= epi3.i;
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scratch[5].i *= epi3.i;
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scratch[3].r = scratch[4].r - scratch[5].i ;
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scratch[3].i = scratch[4].i + scratch[5].r ;
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C_ADD( *Fout1, scratch[0] , scratch[3] );
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scratch[3].r = scratch[4].r + scratch[5].i;
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scratch[3].i = scratch[4].i - scratch[5].r;
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C_ADD( *Fout2, scratch[0] , scratch[3] );
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++Fout0;++Fout1;++Fout2;
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}while(--m);
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}
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/* perform the butterfly for one stage of a mixed radix FFT */
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void bfly_generic(
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kiss_fft_cpx * Fout,
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@ -221,8 +276,11 @@ void fft_work(
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}
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switch (p) {
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case 4: bfly4(Fout,fstride,st,m); break;
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case 2: bfly2(Fout,fstride,st,m); break;
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#if 1
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case 3: bfly3(Fout,fstride,st,m); break;
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#endif
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case 4: bfly4(Fout,fstride,st,m); break;
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default: bfly_generic(Fout,fstride,st,m,p); break;
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}
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}
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@ -1,11 +1,10 @@
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ifeq "$(NFFT)" ""
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NFFT=1024
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NFFT=1024
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endif
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ifeq "$(NUMFFTS)" ""
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NUMFFTS=10000
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NUMFFTS=10000
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endif
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UTILSRC=../kiss_fft.c fftutil.c
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@ -13,7 +12,7 @@ UTILSRC=../kiss_fft.c fftutil.c
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CFLAGS=-Wall -O3 -lm -I.. -ansi -pedantic
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ifeq "$(DATATYPE)" ""
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DATATYPE=float
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DATATYPE=float
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endif
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UTIL=fftutil_$(DATATYPE)
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@ -21,9 +20,9 @@ UTIL=fftutil_$(DATATYPE)
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all: $(UTIL)
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ifeq "$(DATATYPE)" "short"
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TYPEFLAGS=-DFIXED_POINT -Dkiss_fft_scalar=short
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TYPEFLAGS=-DFIXED_POINT -Dkiss_fft_scalar=short
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else
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TYPEFLAGS=-Dkiss_fft_scalar=$(DATATYPE)
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TYPEFLAGS=-Dkiss_fft_scalar=$(DATATYPE)
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endif
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$(UTIL): $(UTILSRC)
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@ -47,7 +46,7 @@ time: all $(RANDDAT)
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POW2=256 512 1024 2048
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POW3=243 729 2187
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mtime: all
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@for n in $(POW2) $(POW3) ;do \
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@for n in $(POW3) ;do \
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export NFFT=$$n;make time; \
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done
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@ -56,7 +55,7 @@ snr: all
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@echo
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@echo "### testing SNR for $(NFFT) point FFTs"
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@echo "#### $(DATATYPE)"
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@echo "testkiss($(NFFT),'$(DATATYPE)',1,1/$(NFFT));" | octave -q
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@echo "testkiss( $(NFFT) , '$(DATATYPE)' );" | octave -q
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test: snr time
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@ -1,11 +1,11 @@
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function snr= testkiss( nfft , prec ,scale_t2f ,scale_f2t )
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if nargin<1, nfft=1024
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endif
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if nargin<2, prec='float'
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endif
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if nargin<3, scale_t2f=1
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endif
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if nargin<4, scale_f2t=1
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function snr= testkiss( nfft , prec )
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if strcmp( prec ,'short')
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scale_t2f=nfft;
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scale_f2t=nfft;
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else
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scale_t2f=1;
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scale_f2t=1/nfft;
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endif
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kfft= sprintf('./fftutil_%s',prec);
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@ -1,11 +1,10 @@
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ifeq "$(NFFT)" ""
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NFFT=1024
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NFFT=1024
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endif
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ifeq "$(NUMFFTS)" ""
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NUMFFTS=10000
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NUMFFTS=10000
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endif
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UTILSRC=../kiss_fft.c fftutil.c
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@ -13,7 +12,7 @@ UTILSRC=../kiss_fft.c fftutil.c
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CFLAGS=-Wall -O3 -lm -I.. -ansi -pedantic
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ifeq "$(DATATYPE)" ""
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DATATYPE=float
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DATATYPE=float
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endif
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UTIL=fftutil_$(DATATYPE)
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@ -21,9 +20,9 @@ UTIL=fftutil_$(DATATYPE)
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all: $(UTIL)
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ifeq "$(DATATYPE)" "short"
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TYPEFLAGS=-DFIXED_POINT -Dkiss_fft_scalar=short
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TYPEFLAGS=-DFIXED_POINT -Dkiss_fft_scalar=short
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else
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TYPEFLAGS=-Dkiss_fft_scalar=$(DATATYPE)
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TYPEFLAGS=-Dkiss_fft_scalar=$(DATATYPE)
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endif
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$(UTIL): $(UTILSRC)
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@ -47,7 +46,7 @@ time: all $(RANDDAT)
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POW2=256 512 1024 2048
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POW3=243 729 2187
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mtime: all
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@for n in $(POW2) $(POW3) ;do \
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@for n in $(POW3) ;do \
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export NFFT=$$n;make time; \
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done
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@ -56,7 +55,7 @@ snr: all
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@echo
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@echo "### testing SNR for $(NFFT) point FFTs"
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@echo "#### $(DATATYPE)"
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@echo "testkiss($(NFFT),'$(DATATYPE)',1,1/$(NFFT));" | octave -q
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@echo "testkiss( $(NFFT) , '$(DATATYPE)' );" | octave -q
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test: snr time
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