The memory usage is very hard to estimate in general. Morever it depends upon a number of factors. Old versions for instance used to keep by default a single set of wavefunctions for one k-point, store those for the other k-points to disk. Since some time the default is to keep wavefunctions for all k-points in memory. Recent versions of QE have a better estimate of how much memory is allocated.
Paolo On Tue, Oct 22, 2019 at 6:10 PM Eric Glen Suter <[email protected]> wrote: > Hi all, > > I'm running jobs with a relatively high number of kpoints with QE 6.2. For > a while I was using the dynamical memory estimates output by the pw.x > executable as a guidepost for requesting memory on a cluster, and this > worked well when I had a relatively small number of kpoints. But it turns > out that for these dense grids I need significantly more than the estimate > indicates. The estimate says a few hundred Mb, but the actual resources > used indicate it's more on the order of several tens of Gb. > > I find in the user manual an estimate of the number of double precision > complex floating point numbers that would be needed ( > > O = mMN + PN + pN1N2N3 + qNr1Nr2Nr3 > ) and this seems to give an estimate on the order of what the output file > says. > > Is there something I'm missing that goes into determining how much memory > a job should take? I'm mostly interested to know if there's a good way to > predict how much memory future jobs will need so I can make a more educated > guess when I request memory. > > Any insights you can offer are greatly appreciated. > > Best regards, > > Eric Suter > > ---------------------------- > > PhD Candidate, Dept. of Physics and Astronomy > > Center for Simulational Physics > > University of Georgia > > ---------------------------- > > email: [email protected] > > phone: 912-856-3071 > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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