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Force Deterministic Algorithm in FFTW?

Posted: 2010-09-07T17:52:08-07:00
by blackhaz
Is it possible to force Magick++ to use deterministic algorithm while doing Fourier transforms?

It looks like my Magick++ app produces slightly different images, sporadically. I suspect this is the fftw issue. I am doing deconvolution so most probably small errors multiply and I am able to notice the difference. I believe it has something to do with fftw running in non-deterministic mode:
http://www.fftw.org/faq/section3.html#nondeterministic

Thank you!

Re: Force Deterministic Algorithm in FFTW?

Posted: 2010-09-13T09:58:35-07:00
by fmw42
This was resolved as a non-issue, I am told. The FFT is in deterministic mode. The problem was really a bad OpenMP that failed sporatically on +ift on Dual Core Intel-based Mac. (So OpenMP needed to be disabled).