mirror/kissfft
1
0
Fork 0
mirror of https://github.com/mborgerding/kissfft.git synced 2025-05-27 21:20:27 -04:00
Code Issues Packages Projects Releases Wiki Activity

radix 4 faster

Browse Source
This commit is contained in:
Mark Borgerding 2003-11-01 03:49:53 +00:00
parent d1df249536
commit 28551899e2
3 changed files with 21 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
kiss_fft.c
View File

@ -127,8 +127,8 @@ void bfly4(
)
{
kiss_fft_cpx *Fout1,*Fout2,*Fout3;
kiss_fft_cpx t1,t2,t3;
kiss_fft_cpx *tw1,*tw2,*tw3;
kiss_fft_cpx scratch[6];
Fout1 = Fout + m;
Fout2 = Fout + 2*m;
@ -138,34 +138,30 @@ void bfly4(
do {
C_FIXDIV(*Fout,4); C_FIXDIV(*Fout1,4); C_FIXDIV(*Fout2,4); C_FIXDIV(*Fout3,4);
C_MUL(t1,*Fout1 , *tw1 );
C_MUL(scratch[0],*Fout1 , *tw1 );
C_MUL(scratch[1],*Fout2 , *tw2 );
C_MUL(scratch[2],*Fout3 , *tw3 );
C_SUB( scratch[5] , *Fout, scratch[1] );
C_ADDTO(*Fout, scratch[1]);
C_ADD( scratch[3] , scratch[0] , scratch[2] );
C_SUB( scratch[4] , scratch[0] , scratch[2] );
C_SUB( *Fout2, *Fout, scratch[3] );
tw1 += fstride;
C_MUL(t2,*Fout2 , *tw2 );
tw2 += fstride*2;
C_MUL(t3,*Fout3 , *tw3 );
tw3 += fstride*3;
*Fout3 = *Fout2 = *Fout1 = *Fout;
C_ADDTO(*Fout,t1);
C_ADDTO(*Fout,t2);
C_ADDTO(*Fout,t3);
C_SUBFROM(*Fout2,t3);
C_SUBFROM(*Fout2,t1);
C_ADDTO( *Fout2,t2);
C_SUBFROM(*Fout3,t2);
C_SUBFROM(*Fout1,t2);
C_ADDTO( *Fout , scratch[3] );
if(st->inverse) {
C_ROTADDTO(*Fout1,t1,3);
C_ROTADDTO(*Fout1,t3,1);
C_ROTADDTO(*Fout3,t1,1);
C_ROTADDTO(*Fout3,t3,3);
Fout1->r = scratch[5].r - scratch[4].i;
Fout1->i = scratch[5].i + scratch[4].r;
Fout3->r = scratch[5].r + scratch[4].i;
Fout3->i = scratch[5].i - scratch[4].r;
}else{
C_ROTADDTO(*Fout1,t1,1);
C_ROTADDTO(*Fout1,t3,3);
C_ROTADDTO(*Fout3,t1,3);
C_ROTADDTO(*Fout3,t3,1);
Fout1->r = scratch[5].r + scratch[4].i;
Fout1->i = scratch[5].i - scratch[4].r;
Fout3->r = scratch[5].r - scratch[4].i;
Fout3->i = scratch[5].i + scratch[4].r;
}
++Fout; ++Fout1; ++Fout2; ++Fout3;
}while(--m);
@ -277,9 +273,7 @@ void fft_work(
switch (p) {
case 2: bfly2(Fout,fstride,st,m); break;
#if 1
case 3: bfly3(Fout,fstride,st,m); break;
#endif
case 4: bfly4(Fout,fstride,st,m); break;
default: bfly_generic(Fout,fstride,st,m,p); break;
}

2
test/Makefile
View File

@ -46,7 +46,7 @@ time: all $(RANDDAT)
POW2=256 512 1024 2048
POW3=243 729 2187
mtime: all
@for n in $(POW3) ;do \
@for n in $(POW2) ;do \
export NFFT=$$n;make time; \
done

2
tools/Makefile
View File

@ -46,7 +46,7 @@ time: all $(RANDDAT)
POW2=256 512 1024 2048
POW3=243 729 2187
mtime: all
@for n in $(POW3) ;do \
@for n in $(POW2) ;do \
export NFFT=$$n;make time; \
done