// Wrapper around FFTW3 that computes the real-valued inverse Fourier transform
// of a complex-valued frequantial image.
// The input data must be hermitic.
static void ifft_2dfloat(float *ifx, fftwf_complex *fx, int w, int h)
{
fftwf_complex *a = fftwf_xmalloc(w*h*sizeof*a);
fftwf_complex *b = fftwf_xmalloc(w*h*sizeof*b);
//fprintf(stderr, "planning...\n");
evoke_wisdom();
fftwf_plan p = fftwf_plan_dft_2d(h, w, a, b,
FFTW_BACKWARD, FFTW_ESTIMATE);
bequeath_wisdom();
//fprintf(stderr, "...planned!\n");
FORI(w*h) a[i] = fx[i];
fftwf_execute(p);
float scale = 1.0/(w*h);
FORI(w*h) {
fftwf_complex z = b[i] * scale;
ifx[i] = crealf(z);
if (FIWARN() > 0)
{
if (cimagf(z) > 0.001)
fail("z is not real {cimagf(z)=%g} (set FIWARN=0 to run anyway)", cimagf(z));
//assert(cimagf(z) < 0.001);
}
}
// wrapper around FFTW3 that computes the complex-valued Fourier transform
// of a real-valued image
static void fft_2dfloat(fftwf_complex *fx, float *x, int w, int h)
{
fftwf_complex *a = fftwf_malloc(w*h*sizeof*a);
//fprintf(stderr, "planning...\n");
evoke_wisdom();
fftwf_plan p = fftwf_plan_dft_2d(h, w, a, fx,
FFTW_FORWARD, FFTW_ESTIMATE);
bequeath_wisdom();
//fprintf(stderr, "...planned!\n");
FORI(w*h) a[i] = x[i]; // complex assignment!
fftwf_execute(p);
fftwf_destroy_plan(p);
fftwf_free(a);
fftwf_cleanup();
}
// Wrapper around FFTW3 that computes the real-valued inverse Fourier transform
// of a complex-valued frequantial image.
// The input data must be hermitic.
static void ifft_2dfloat(float *ifx, fftwf_complex *fx, int w, int h)
{
fftwf_complex *a = fftwf_malloc(w*h*sizeof*a);
fftwf_complex *b = fftwf_malloc(w*h*sizeof*b);
//fprintf(stderr, "planning...\n");
evoke_wisdom();
fftwf_plan p = fftwf_plan_dft_2d(h, w, a, b,
FFTW_BACKWARD, FFTW_ESTIMATE);
bequeath_wisdom();
//fprintf(stderr, "...planned!\n");
FORI(w*h) a[i] = fx[i];
fftwf_execute(p);
float scale = 1.0/(w*h);
FORI(w*h) {
fftwf_complex z = b[i] * scale;
ifx[i] = crealf(z);
//assert(cimagf(z) < 0.001);
}