void ifftc(unsigned int D, const long dimensions[__VLA(D)], unsigned long flags, complex float* dst, const complex float* src)
{
ifftmod(D, dimensions, flags, dst, src);
ifft(D, dimensions, flags, dst, dst);
ifftmod(D, dimensions, flags, dst, dst);
}
void compute_imgcov(const long cov_dims[4], complex float* imgcov, const long nskerns_dims[5], const complex float* nskerns)
{
debug_printf(DP_DEBUG1, "Zeropad...\n");
long xh = cov_dims[0];
long yh = cov_dims[1];
long zh = cov_dims[2];
long kx = nskerns_dims[0];
long ky = nskerns_dims[1];
long kz = nskerns_dims[2];
long channels = nskerns_dims[3];
long nr_kernels = nskerns_dims[4];
long imgkern_dims[5] = { xh, yh, zh, channels, nr_kernels };
complex float* imgkern1 = md_alloc(5, imgkern_dims, CFL_SIZE);
complex float* imgkern2 = md_alloc(5, imgkern_dims, CFL_SIZE);
md_resize_center(5, imgkern_dims, imgkern1, nskerns_dims, nskerns, CFL_SIZE);
// resort array
debug_printf(DP_DEBUG1, "FFT (juggling)...\n");
long istr[5];
long mstr[5];
long idim[5] = { xh, yh, zh, channels, nr_kernels };
long mdim[5] = { nr_kernels, channels, xh, yh, zh };
md_calc_strides(5, istr, idim, CFL_SIZE);
md_calc_strides(5, mstr, mdim, CFL_SIZE);
long m2str[5] = { mstr[2], mstr[3], mstr[4], mstr[1], mstr[0] };
ifftmod(5, imgkern_dims, FFT_FLAGS, imgkern1, imgkern1);
ifft2(5, imgkern_dims, FFT_FLAGS, m2str, imgkern2, istr, imgkern1);
float scalesq = (kx * ky * kz) * (xh * yh * zh); // second part for FFT scaling
md_free(imgkern1);
debug_printf(DP_DEBUG1, "Calculate Gram matrix...\n");
int cosize = channels * (channels + 1) / 2;
assert(cov_dims[3] == cosize);
#pragma omp parallel for collapse(3)
for (int k = 0; k < zh; k++) {
for (int j = 0; j < yh; j++) {
for (int i = 0; i < xh; i++) {
complex float gram[cosize];
gram_matrix2(channels, gram, nr_kernels, (const complex float (*)[nr_kernels])(imgkern2 + ((k * yh + j) * xh + i) * (channels * nr_kernels)));
#ifdef FLIP
// add (scaled) identity matrix
for (int i = 0, l = 0; i < channels; i++)
for (int j = 0; j <= i; j++, l++)
gram[l] = ((i == j) ? (kx * ky * kz) : 0.) - gram[l];
#endif
for (int l = 0; l < cosize; l++)
imgcov[(((l * zh) + k) * yh + j) * xh + i] = gram[l] / scalesq;
}
}
}
md_free(imgkern2);
}
