vijaya65 at hotmail.com
Wed Jun 12 19:30:11 CEST 2013
Thanks for your reply. I had started an earlier thread under the same heading and
you had replied-no other reason for using your name only. I should have continued it but it was a
few weeks old.
> From: paolo.giannozzi at uniud.it
> To: pw_forum at pwscf.org
> Date: Wed, 12 Jun 2013 18:30:23 +0200
> Subject: Re: [Pw_forum] Parallelization
> On Tue, 2013-06-11 at 19:57 +0000, vijaya subramanian wrote:
> > Hi Paolo
> you know, there are 1605 subscribed user on the pw_forum mailing list.
> Even if part of them are actually disabled, it is a lot of people.
> Why do you address to me?
> Your unit cells are quite large, your cutoff is not small, and you
> use spin-orbit, a feature that increases the memory footprint and
> is less optimized than "plain-vanilla" calculations. In order to
> run such large jobs, one needs to know quite a bit about the
> inner working of parallelization, which arrays are distributed,
> which are not ... The following arrays, for instance:
> > Each <psi_i|beta_j> matrix 350.63 Mb ( 5440, 2, 2112)
> are not distributed. This is the kind of arrays that causes bottlenecks.
> If you have N mpi processes per node, you have N such arrays filling
> the same physical memory. Reducing the number of MPI processes per node
> and using OpenMP instead might be a good strategy.
> Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
> Pw_forum mailing list
> Pw_forum at pwscf.org
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