Dear Professor Giannozzi, So if I understand you correctly, you did something like
mpirun -np 18 pp.x -in Fe.pp.ldos.in on the nscf data wirh 14x14x14 and got the 560 cube files in 30 minutes? This is what I would expect/hope for as well. I will try this and if I cannot reproduce it there might be something wrong with my installation. Kind regards Lenz Am So., 21. März 2021 um 16:31 Uhr schrieb Paolo Giannozzi < [email protected]>: > A LDOS calculation should take more or less the same time as the > calculation of the charge density, plus reading, wroting, etc.. I just > tried and it took half an hour on 18 processors (CPU cores, not GPUs) > > Paolo > > On Wed, Mar 17, 2021 at 5:26 PM Lenz Fiedler <[email protected]> > wrote: > >> Dear Professor Giannozzi, >> >> Thank you so much for your answer. You are right, I did not really think >> about the parallelization for the initial SCF calculation, I was more >> puzzled by the pp.x calculation. If I understand you correctly, using >> something like "pp.x -nk 16" might also help speed up the LDOS calculation >> as well? But there also might be an upper limit of how fast this performs >> and it could be that I simply have to wait a while to obtain the LDOS? As >> in, except for my suboptimal parallelization strategy, the long runtime of >> pp.x I observed was not due to wrong usage but simply to computational load >> of the problem? >> >> Kind regards >> Lenz Fiedler >> >> PhD Student (HZDR / CASUS) >> >> >> Am Di., 16. März 2021 um 16:36 Uhr schrieb Paolo Giannozzi < >> [email protected]>: >> >>> Your supercell is small but you have a high cutoff and a large number of >>> k-points, which makes the overall computational load quite heavy. Moreover >>> your choice of parallelization is less than optimal: you should use both >>> k-point and plane-wave parallelization, something like "mpirun -np 160 pw.x >>> -nk 16" or so. For reference: I ran your Fe.pw.scf.in input in 20' on a >>> small 36-core machine with two (powerful) GPU's. The nscf calculation took >>> 1h20' for the calculation and is taking as much time if not more to write >>> the files. Also note that not all postprocessing calculations are optimized >>> for large runs. >>> >>> Paolo >>> >>> On Mon, Mar 15, 2021 at 7:23 PM Lenz Fiedler <[email protected]> >>> wrote: >>> >>>> (resent because something went wrong with the header line) >>>> >>>> Hi users, >>>> >>>> I am experiencing a problem with pp.x. I want to calculate the LDOS for >>>> a 16 Fe atom supercell using a 560 value energy grid and the 3D grid given >>>> by the DFT calculation (100x100x100 grid points). I have performed the DFT >>>> calculation by first doing a SCF calculation (8x8x8 k-points) and then a >>>> non-SCF calculation (14x14x14 k-points) successfully. Now I am trying to >>>> do: >>>> >>>> mpirun -np 160 pp.x -in Fe.pp.ldos.in >>>> >>>> but the calculation takes way longer than I anticipated. The entire DFT >>>> calculation took less than a day, while for the LDOS, after about 12 hours, >>>> only 20 tmp files had been written. Am I doing something wrong? Or is this >>>> expected? At this rate, calculating the LDOS would take days, which is why >>>> I am assuming I am doing something wrong. >>>> Please find my output and input files here: >>>> >>>> >>>> https://drive.google.com/drive/folders/1R-m5jlw1bcNxe3nBXjc4dms-IoMMp4Ir?usp=sharing >>>> (the pp.out file is from a run where I investigated if a lower number >>>> of CPUs helps, but that was slower, as expected.) >>>> >>>> Kind regards >>>> Lenz >>>> >>>> PhD Student (HZDR / CASUS) >>>> _______________________________________________ >>>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu) >>>> 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 206, 33100 Udine, Italy >>> Phone +39-0432-558216, fax +39-0432-558222 >>> >>> _______________________________________________ >>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu) >>> users mailing list [email protected] >>> https://lists.quantum-espresso.org/mailman/listinfo/users >> >> _______________________________________________ >> Quantum ESPRESSO is supported by MaX (www.max-centre.eu) >> 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 206, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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