Assume I have a variable u, which is an $m\times n$ array filled with exclusively real values. I want to find the maximum value within this u array, given its Fourier Transform U, i.e u = np.fft.ifft2(U). Is it possible to obtain this maximum value without doing a full Inverse Fourier Transform?
I'm thinking some type of mathematical trick like Parseval's Theorem might be helpful. I want to avoid the full inverse transform if at all possible due to the computational cost. I would appreciate any help this site's users could provide.