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Asked: 2026-05-22T20:50:54+00:00

I studied the Cooley Tukey algorithm and I understood it. I got everything in

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I studied the Cooley Tukey algorithm and I understood it. I got everything in the CUDA convolutionFFT2D example till these kernels:

spProcess2D calls -> spProcess2D_kernel which calls a lot of -> spPostprocessC2C, mulAndScale and spPreprocessC2C

Here’s the complete code:
http://nopaste.info/30c13e44fe.html (convolutionFFT2D.cu, here is the spProcess2D function)
http://nopaste.info/78d22afac2.html (convolutionFFT2D.cuh, here are the other functions)

I already read all the nvidia sdk papers but I can’t still figure out what these function do (they use twiddles, but nothing seems like a Cooley Tukey algorithm there)

Please help me if you can, or at least point me out where to solve my problem

Update: I found this link: http://cnx.org/content/m16336/latest/#uid38
Maybe these functions are performing a breadth-first algorithm? I still can’t say that but the shape seems the same

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1 Answer

  1. Editorial Team

    It looks like the algorithm is doing something similar to the algorithm mentioned here. The preprocess step looks to be re-ordering the Real input of size N (after padding) to complex input of size N/2. The postprocess step is re-ordering the data to get back the FFT of the original
    input array.

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