[Insight-users] ITK FFTW vs system FFTW

[Simon Rit]

Hi,
We have recently observed on a fedora distribution that FFTW is two
times slower when one uses the ITK compilation
(USE_SYSTEM_FFTW:BOOL=OFF, default) than when one uses the system fftw
(USE_SYSTEM_FFTW:BOOL=ON).

We have looked for an explanation in the flags (the Fedora flags are
available here http://pkgs.fedoraproject.org/cgit/fftw.git/tree/fftw.spec)
but we have not managed to figure it out. Would someone happen to have
an explanation and solution?

Thanks in advance,
Simon