void fft_8()
{
double aRe[4], aIm[4], bRe[4], bIm[4], gem;
aRe[0] = zRe[0]; bRe[0] = zRe[1];
aRe[1] = zRe[2]; bRe[1] = zRe[3];
aRe[2] = zRe[4]; bRe[2] = zRe[5];
aRe[3] = zRe[6]; bRe[3] = zRe[7];
aIm[0] = zIm[0]; bIm[0] = zIm[1];
aIm[1] = zIm[2]; bIm[1] = zIm[3];
aIm[2] = zIm[4]; bIm[2] = zIm[5];
aIm[3] = zIm[6]; bIm[3] = zIm[7];
fft_4(aRe, aIm); fft_4(bRe, bIm);
gem = c8*(bRe[1] + bIm[1]);
bIm[1] = c8*(bIm[1] - bRe[1]);
bRe[1] = gem;
gem = bIm[2];
bIm[2] =-bRe[2];
bRe[2] = gem;
gem = c8*(bIm[3] - bRe[3]);
bIm[3] =-c8*(bRe[3] + bIm[3]);
bRe[3] = gem;
zRe[0] = aRe[0] + bRe[0]; zRe[4] = aRe[0] - bRe[0];
zRe[1] = aRe[1] + bRe[1]; zRe[5] = aRe[1] - bRe[1];
zRe[2] = aRe[2] + bRe[2]; zRe[6] = aRe[2] - bRe[2];
zRe[3] = aRe[3] + bRe[3]; zRe[7] = aRe[3] - bRe[3];
zIm[0] = aIm[0] + bIm[0]; zIm[4] = aIm[0] - bIm[0];
zIm[1] = aIm[1] + bIm[1]; zIm[5] = aIm[1] - bIm[1];
zIm[2] = aIm[2] + bIm[2]; zIm[6] = aIm[2] - bIm[2];
zIm[3] = aIm[3] + bIm[3]; zIm[7] = aIm[3] - bIm[3];
} /* fft_8 */
void twiddleTransf(int sofarRadix, int radix, int remainRadix,
T3 yRe[], T4 yIm[])
{ /* twiddleTransf */
double cosw, sinw, gem;
initTrig(radix);
omega = 2*M_PI/(double)(sofarRadix*radix);
cosw = cos(omega);
sinw = -sin(omega);
tw_re = 1.0;
tw_im = 0;
dataOffset=0;
groupOffset=dataOffset;
adr=groupOffset;
for (dataNo=0; dataNo<sofarRadix; dataNo++)
{
if (sofarRadix>1)
{
twiddleRe[0] = 1.0;
twiddleIm[0] = 0.0;
twiddleRe[1] = tw_re;
twiddleIm[1] = tw_im;
for (twNo=2; twNo<radix; twNo++)
{
twiddleRe[twNo]=tw_re*twiddleRe[twNo-1]
- tw_im*twiddleIm[twNo-1];
twiddleIm[twNo]=tw_im*twiddleRe[twNo-1]
+ tw_re*twiddleIm[twNo-1];
}
gem = cosw*tw_re - sinw*tw_im;
tw_im = sinw*tw_re + cosw*tw_im;
tw_re = gem;
}
for (groupNo=0; groupNo<remainRadix; groupNo++)
{
if ((sofarRadix>1) && (dataNo > 0))
{
zRe[0]=yRe[adr];
zIm[0]=yIm[adr];
blockNo=1;
do {
adr = adr + sofarRadix;
zRe[blockNo]= twiddleRe[blockNo] * yRe[adr]
- twiddleIm[blockNo] * yIm[adr];
zIm[blockNo]= twiddleRe[blockNo] * yIm[adr]
+ twiddleIm[blockNo] * yRe[adr];
blockNo++;
} while (blockNo < radix);
}
else
for (blockNo=0; blockNo<radix; blockNo++)
{
zRe[blockNo]=yRe[adr];
zIm[blockNo]=yIm[adr];
adr=adr+sofarRadix;
}
switch(radix) {
// T.Grill - replaced the inlined code by their function counterparts
case 2 : fft_2(zRe,zIm); break;
case 3 : fft_3(zRe,zIm); break;
case 4 : fft_4(zRe,zIm); break;
case 5 : fft_5(zRe,zIm); break;
case 8 : fft_8(); break;
case 10 : fft_10(); break;
default : fft_odd(radix); break;
}
adr=groupOffset;
for (blockNo=0; blockNo<radix; blockNo++)
{
yRe[adr]=zRe[blockNo]; yIm[adr]=zIm[blockNo];
adr=adr+sofarRadix;
}
groupOffset=groupOffset+sofarRadix*radix;
adr=groupOffset;
}
dataOffset=dataOffset+1;
groupOffset=dataOffset;
adr=groupOffset;
}
} /* twiddleTransf */
