[CP2K:6325] FFTW "Wisdom" support removed?

[Iain Bethune]

Hi Martin,

The cp2k-wisdom script was removed because it was unmaintained and (to our knowledge) unused.  I had a look at it and it appears to generate only wisdom for 3D FFTs which is not usually what you want for parallel runs, and also only support cubic cells.

In any case, CP2K will at the end of a run write a wisdom file for you to the location specified in GLOBAL%FFTW_WISDOM_FILE_NAME, which defaults to /etc/fftw/wisdom.  This will contain wisdom for the FFT sizes and types that are relevant for your calculation.  So best thing to do it to set this to be somewhere writable for non-root users, then run once with FFTW_PLAN_TYPE PATIENT or even EXHAUSTIVE.  Then subsequent runs you should find the planning time significantly reduced, as the wisdom file should be read.  Let me know if it’s not working for you!

- Iain

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Iain Bethune
Project Manager, EPCC

Email: ibet... at epcc.ed.ac.uk
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> On 30 Mar 2015, at 13:25, M. Brehm <brehmin... at googlemail.com> wrote:
> 
> Dear Community,
> 
> in older versions of CP2k, there was a small script called "cp2k-wisdom" in the tools subdirectory of the CP2k trunk, which was able to produce planning data for FFTW, such that CP2k runs were able to profit from optimal algorithms for a given machine without the need to use "FFTW_PLAN_TYPE PATIENT" each time.
> 
> However, this script was removed from the trunk some time ago, and there seems to be no replacement. Why was it removed? Was there some problem with Wisdom in CP2k? I would like to use this feature for my calculations. Would it be a good idea to just use the old version of the script from an older revision?
> 
> Best regards,
> Martin
> 
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