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what is the difference between fftw3 and matlab while calculate ifft? #259

Open darkgirl opened 2 years ago

darkgirl commented 2 years ago

Hi,

I found a very strange problem. when i input an array with 513 elements, the output array is not exactly correct. The first element in the output array is the second element of matlab ifft output array, The second element in the output array is the third element of matlab ifft output array.... The last element in the output array is the first element of matlab ifft output array. and the imag(Imaginary part) of all the elements in the output array is contrary to matlab output.

Lqlsoftware commented 2 years ago

Can you provide more information like log or file (include the original data seq)?

stevengj commented 2 years ago

Note that slight differences (on the order of 1e-14, for example) are expected simply due to differences in floating-point roundoff errors from slightly different algorithms.