When VASP 5 was released, the performance was mostly slower than our make of VASP 4.6. I wrote it off as an optimization issue, and went on in my life. Then, in VASP 5.2, with the release notes, I realized that the it was all due to slower FFT, and is now fixed. Is there any way for me, as a user, to tell if the VASP make that I am using is built with the faster FFTW?
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$\begingroup$ If you are still working with VASP and run into any questions, you might be interested in Matter Modeling SE $\endgroup$– TyberiusNov 11 '21 at 16:40
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There are a few possibilities:
- Ask whoever built it. :)
- Run strings vasp | grep -i fft and see if there's evidence of the version buried in the executable.
- Run ldd vasp and look for a dynamically linked fft library. This last option is unlikely to produce results because you're more likely to have a static FFTW library (if I recall the build process for FFTW correctly).
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4$\begingroup$ To expand on this answer, you could also try:
nm vasp | grep fftwto take a look for some of the FFTW symbols assuming that the executable hasn't been stripped. $\endgroup$ Nov 30 '11 at 13:13 -
$\begingroup$ That's a great point, Aron, though I recommend
grep -iin this context. $\endgroup$ Dec 2 '11 at 15:04