[gmx-users] SSE4 → AVX2

Szilárd Páll pall.szilard at gmail.com
Wed Aug 27 12:00:52 CEST 2014

Normally the highest supported SIMD instructions set, which is in your
case AVX2, is detected during configuration phase. The fact that you
are getting that message means that:
- you are cross-compiling on an SSE4.1 node (e.g. cluster head node)
for AVX2 machines;
- your compiler does not support AVX/AVX2 and SSE4.1 was chosen as
fallback; cmake should have warned about this during configuration.

What is your hardware/software setup? Using -DGMX_SIMD=AVX2 should
work in the former case.



On Wed, Aug 27, 2014 at 10:44 AM, nicola staffolani
<n.staffolani at unitus.it> wrote:
> Dear Gromacs users & developers,
> my computer tells me that, if I'd use AVX_256 instead of SSE4, then my
> simulations would be done much faster. Which changes in which files do I
> have to do in order to achieve this? I have serched the mailing list but
> couldn't find the explicit answer: I warn you that I am not so much of a
> geek, therefore suggesting me, for example, to change the path, without
> telling me which precise actions I have to carry on (for example, as
> already said, which lines I have to change/add in which file) in order to
> achieve this, will only generate the next email from my side and then,
> since by then you will have already started answering me, you will lose
> more time answering me back than if you would have precisely described in
> the first reply the order of precise actions needed to be done in order to
> achieve the goal ;)
> Thank you for helping and have a nice day/night,
> Nicola
> --
> Nicola Staffolani PhD
> Biophysics & Nanoscience Centre CNISM <http://www.unitus.it/biophysics>
> Università della Tuscia
> Largo dell'Università s.n.c., I-01100 Viterbo
> email: n.staffolani at unitus.it
> tel.: +39 0761 35 70 27; fax: +39 0761 35 71 36
> --
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