We know that cufftExecR2C() returns only the non-redundant FFT complex coefficients, due to simmetry in the Fourier transform of a real function.

For a 1D transform, the expression for the simmetry should be, AFAIK:

F(k) = F(n-k)*

Now: for a 2D R2C transform, say of a WxH real matrix, cufftExecR2C() returns a Wx(H/2 + 1) complex matrix, with non-redundant coefficients only.

What’s the formula to “fill in” the missing coefficients and have a complete WxH transformed matrix?
It’s not so trivial, for me at least, to figure out the right simmetry for 2D. :blink:

Hi, Have you had any luck in solving this problem? If so, please let me know. I am faced with a similar problem and am considering rewriting an FFT algorithm (which I do not want to) because I havent been able to figure out how to get back the missing values and unjumble the CUFFT results. Thanks