Re: NXC: Fast Fourier Transformation (FFT) for NXT
Posted: 14 Jul 2011, 16:27
the 1st: this way?
the 2nd: no problem:
Code: Select all
i=0;
while (i<nn-1) {
if (i < j) {
tx = fx_[i];
ty = fy_[i];
fx_[i] = fx_[j];
fy_[i] = fy_[j];
fx_[j] = tx;
fy_[j] = ty;
}
k = i2;
while (k <= j) {
j -= k;
k >>= 1;
}
j += k;
++i;
}
Code: Select all
for (i=j;i<nn;i+=l2) {
i1 = i + l1;
tx=fx_[i1];
ty=fy_[i1];
t1 = u1 * tx - u2 * ty ;
t2 = u1 * ty + u2 * tx ;
fx_[i1] = fx_[i] - t1;
fy_[i1] = fy_[i] - t2;
fx_[i] += t1;
fy_[i] += t2;
}