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mpicbg-scicomp / gearshifft_publication

Publication Manuscript for results obtained with gearshifft
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r2c fp32 outofplace fftw wisdom is missing (2D, 3D) #29

Open psteinb opened 7 years ago

psteinb commented 7 years ago

just about to add a figure on this comparing fftw_estimate, fftw_measure and fftw_wisdom_only, but found out that these values are missing in the results @tdd11235813 are they lost or were they never produced?

tdd11235813 commented 7 years ago

they should be there, fftw wisdoms were generated for some radix-2 sizes only, but in all flavors (=real and complex, forward and backwards, in-place and out-of-place transforms). See results here

tdd11235813 commented 7 years ago

oh, you mean 2D and 3D shapes, right? FFTW wisdom manual says it creates wisdoms for 2D and 3D whose extents are equivalent to the 1D case ... weird, they are indeed missing :/

tdd11235813 commented 7 years ago

Ok, found the problem. (My job logfiles show that these out-of-place transforms indeed were not produced.) The code fftw-wisdom.c contains this if statement:

 if (!strchr(canonical_sizes[i],'x') 
     || !strchr(types[j],'o')) {   
    // ... add problem

This means, 1D extents use out-of-place, and 2D/3D (contains 'x') do not, so these sizes were excluded by fftw-wisdom code.

edit: This is not documented by FFTW, at least on this FFTW page

psteinb commented 7 years ago

ok, very good piece of information I think. I have to address this in the text (tomorrow) and of course we should file a bug report to the authors of FFTW if time permits. thanks for the investigation. I'll leave this issue open for now