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NPAR
Posted: Thu Mar 19, 2015 3:12 pm
by nkwem
Dear all,
I know that NPAR = sqrt(number of cores) but I'm not sure if number of cores are per node or is it the total cores that I have requested. Please help
Regards,
Nkwe
Re: NPAR
Posted: Thu Mar 19, 2015 5:19 pm
by alex
I'd like to see the number as number of tasks.
Cheers,
alex
Re: NPAR
Posted: Mon Mar 23, 2015 10:16 am
by nkwem
Hi Alex,
Thank you for the reply.
Is it number of tasks per node or total number of tasks?
Regards,
Nkwe
Re: NPAR
Posted: Tue Mar 24, 2015 1:47 pm
by andydihao
I put it as sqrt(cores per node) and it worked fine for PBE.
Best regards,
Andy
Re: NPAR
Posted: Wed Mar 25, 2015 8:57 am
by marsoner
Re: NPAR
Posted: Thu Mar 26, 2015 10:36 am
by alex
Hello Nkwe,
sorry for the late answer. My browser seems to have swallowed it. :-O
NPAR relates to the total number of tasks. E.g. 8 CPUs with 8 cores each, one task on every core = 64 tasks. Then you start with an NPAR of 8.
Please consider it as a starting point. As Lukas pointed out, there might be an optimum setting for your own machine, which might be different from that starting point.
I normally do some steps in wavefunction optimisation for different NPAR settings and pick the fastest. Starting point is sqrt(tasks).
Cheers,
alex