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radix 3 fixed point still broken

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This commit is contained in:
Mark Borgerding 2003-10-17 02:59:32 +00:00
parent 31d4214f44
commit 6f8bcedc24
3 changed files with 26 additions and 45 deletions
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67
kiss_fft.c
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@ -155,6 +155,10 @@ void bfly2(
do{
C_MUL (t, *Fout2 , *twiddles);
twiddles += fstride;
#ifdef FIXED_POINT
Fout->r>>=1; Fout->i>>=1;
t.r>>=1; t.i>>=1;
#endif
C_SUB( *Fout2 , *Fout , t );
C_ADDTO( *Fout , t );
++Fout2;
@ -177,55 +181,35 @@ void bfly3(
kiss_fft_cpx * scratch = st->scratch;
kiss_fft_cpx * twiddles = st->twiddles;
kiss_fft_cpx t[6];
//kiss_fft_cpx epi3 = twiddles[fstride*m];
kiss_fft_cpx epi3 = { -0.5 , -0.866025403784439 };
kiss_fft_cpx nepi3 = { -0.5 , 0.866025403784439 };
if ( st->inverse){
epi3.i *=-1;
nepi3.i *=-1;
}
kiss_fft_cpx epi3;
//kiss_fft_cpx epi3 = { -0.5 , -0.866025403784439 };
epi3 = twiddles[fstride*m];
Fout0=Fout;
Fout1=Fout0+m;
Fout2=Fout0+2*m;
//printf("epi3=%e,%ei\n",epi3.r,epi3.i);
for ( u=0; u<m; ++u ) {
kiss_fft_cpx sum01,sum23,t0pt1,t0mt1;
kiss_fft_cpx sum23,t0pt1,t0mt1;
#ifdef FIXED_POINT
Fout0->r /= 3; Fout0->i /= 3;
Fout1->r /= 3; Fout1->i /= 3;
Fout2->r /= 3; Fout2->i /= 3;
#endif
Fout0=Fout++;
Fout1=Fout0+m;
Fout2=Fout0+2*m;
scratch[0] = *Fout0;
// st->nfft = 3*m*fstride
C_MUL(t[0],*Fout1 , twiddles[fstride*u ] );
C_MUL(t[1],*Fout2 , twiddles[fstride*u*2] );
C_ADD(sum01,t[0], t[1] );
//C_MUL(t[2],t[0] , epi3 );
//C_MUL(t[3],t[1] , nepi3);
C_MUL(t[5],t[1] , epi3);
C_MUL(t[4],t[0] , nepi3);
C_ADD(*Fout0,scratch[0],sum01);
/*
t0 * (-.5 , -.867j )
+ t1 * (-.5 , .867j )
t0.r * -.5 - t0.r * .867 j - t0.i * .5 j + t0.i * .867
+
t1.r * -.5 + t1.r * .867 j - t1.i * .5 j - t1.i * .867
( t0.r * -.5 + t0.i * .867 - t1.r * .5 - t1.i * .867)
+
j*(t0.r * -.867 + t1.r * .867 + t0.i * -.5 + t1.i * -.5)
-.5 * ( t0.r + t1.r) + .867 * (t0.i - t1.i )
+
-.867j * (t0.r - t1.r ) - .5 * (t0.i + t1.i )
* */
C_ADD(t0pt1,t[0],t[1]);
t0pt1.r *= -.5;
t0pt1.i *= -.5;
C_ADD(*Fout0,scratch[0],t0pt1);
t0pt1.r /= -2;
t0pt1.i /= -2;
C_SUB(t0mt1,t[0],t[1]);
t0mt1.r *= epi3.i;
t0mt1.i *= epi3.i;
@ -239,10 +223,7 @@ void bfly3(
sum23.i = t0pt1.i - t0mt1.r;
C_ADD( *Fout2, scratch[0] , sum23 );
// Fout1->r = scratch[0].r + t[2].r + t[3].r;
// Fout1->i = scratch[0].i + t[2].i + t[3].i;
// Fout2->r = scratch[0].r + t[4].r + t[5].r;
// Fout2->i = scratch[0].i + t[4].i + t[5].i;
++Fout0;++Fout1;++Fout2;
}
}

2
test/Makefile
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@ -1,4 +1,4 @@
NFFT=2187
NFFT=2048
ALLUTILS=kfft kffts kfftd
NUMFFTS=10000
UTILSRC=../kiss_fft.c fftutil.c

2
tools/Makefile
View File

@ -1,4 +1,4 @@
NFFT=2187
NFFT=2048
ALLUTILS=kfft kffts kfftd
NUMFFTS=10000
UTILSRC=../kiss_fft.c fftutil.c