If the input file is correct? On Thu, Aug 6, 2015 at 4:30 PM, Merlin Meheut <merlin.meh...@get.obs-mip.fr> wrote:
> On 05/08/2015 18:50, Andrea Dal Corso wrote: > > On Wed, 2015-08-05 at 17:18 +0200, Merlin Meheut wrote: > >> Dear PWSCF users, > >> > >> I recently discovered with great interest the possibilities to > >> parallelize phonon calculations using the -nimage option of ph.x. > >> (example given in espresso-4.3.2/examples/GRID_examples). > >> > > GRID examples refer to grid splitting, meaning that you split the > > calculation using start_irr, last_irr etc. and in principle the > > calculation can run in different machines. Then you have to collect the > > files yourself to finally obtain the results. > > Sorry I mixed up both. Actually, I used -nimage (as explained in > Doc/INPUT_PH.txt of version 4.3.2), but I would like to restart with > grid splitting. > Thank you for the reference to the example. > > >> However, I had a problem when performing calculations at gamma-point: > >> for other q-points (therefore with epsil=.false. and zue=.false.) > >> everything went as planned, but with q=0 (and epsil=.true. and > >> zue=.true.), this just did not work. I took 80 processors divided into 4 > >> images, and instead of dividing the different representations into 4 > >> pools, the four groups of processors realized the same calculation, > >> computing the same representations. I killed the calculation at some > >> point (I have computed the electric fields, effective charges and 218 > >> representations out of 564). I would like now to finish the computation > >> without redoing it, and I have several questions to achieve this goal: > >> > > Are you sure that all the images made the same phonon calculations, or > > all images made the electric field calculation but the phonon modes were > > different? > > The names of the partial dynamical matrices (dynmat.1.$irr.xml) are the > same, the files (e.g. _ph0/LiClMag2-1.phsave/dynmat.1.100.xml and > _ph1/LiClMag2-1.phsave/dynmat.1.100.xml) are almost identical, and the > calculation lasted more than it should have (each of the 4 separate > images has computed more than 141 representations, which is one quarter > of the total). So as far as I understand it, all the images made > electric field calculation and started making the same phonon mode > calculations in parallel. > > > In this case, since you stopped the calculation, you can only > > collect the .xml files in a single _ph0 directory and restart without > > images. The restart with images is still poorly supported. > > I would like to restart without -nimage (since it seems to fail in > this particular case), but with grid splitting. Do you think this is > presomptuous? > By the way, I had a positive experience restarting with -nimage on > another run (at q neq 0) . > > > In the last version of QE, the dielectric constant and effective charges > > are saved in the tensors.xml file in the _ph0 directory. > > Thank you very much for your help! > > Best regards, > > > -- > Merlin MĂ©heut, GĂ©osciences et Environnement Toulouse, > OMP, 14 avenue Edouard Belin, 31400 Toulouse, France > > phone +33 (0)5 61 33 26 17, fax +33 (0)5 61 33 25 60 > > _______________________________________________ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum
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