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<p>Dear Kiran,<br>
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<p>if I look at the run_example_1 I see that there is only the splitting via the q points.<br>
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<p>An irrep, or irreducible representation is the (possibly) degenerated phonon mode<br>
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<p>at one q point... Splitting in q points is much easier than on irreps which I would not<br>
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<p>recommend it for a beginner...<br>
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<p>Cheers<br>
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<p>Thomas<br>
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<pre class="moz-signature" cols="72"><font size="3">--<br>Dr. rer. nat. Thomas Brumme<br>Theoretical chemistry<br>TU Dresden - BAR / II49<br>Helmholtzstr. 18<br>01069 Dresden<br><br>Tel: +49 (0)351 463 40844<br><br><font color="000000">email: thomas.brumme@tu-dresden.de</font></font><br></pre>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>Von:</b> Kiran Yadav <kiranyadav0816@gmail.com><br>
<b>Gesendet:</b> Dienstag, 24. November 2020 13:22<br>
<b>An:</b> Brumme, Thomas<br>
<b>Betreff:</b> Re: [QE-users] QE Parallelization for Phonon Dispersion calculations</font>
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<div dir="ltr">Dear Dr Thomas,
<div>Thanks a lot for the reference. I looked at the run example and run example 1, In the run example, they have "<span style="color:rgb(0,0,0); white-space:pre-wrap">Both q-points and irreps are split." If possible please answer on - What are irreps here
and how does it affects our phonon calculation parallelization?</span></div>
<div><span style="color:rgb(0,0,0); white-space:pre-wrap">From my output file, I got 20 q-points and q in seq '1 20' but couldn't find irr.
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<div><font face="verdana, sans-serif">KIndly help.</font></div>
<div><font face="verdana, sans-serif">Thanks a lot again</font></div>
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<div><font face="verdana, sans-serif">Regards</font></div>
<div dir="ltr"><font face="verdana, sans-serif">Kiran Yadav</font></div>
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<div dir="ltr" class="gmail_attr">On Tue, Nov 24, 2020 at 5:10 PM Thomas Brumme <<a href="mailto:thomas.brumme@tu-dresden.de">thomas.brumme@tu-dresden.de</a>> wrote:<br>
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<p>Dear Kiran,<br>
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<p>please have a look at the GRID_example in the PHonon examples and there the run_example_1 in particular.<br>
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<p>Regards<br>
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<p>Thomas<br>
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<pre cols="72"><font size="3">--<br>Dr. rer. nat. Thomas Brumme<br>Theoretical chemistry<br>TU Dresden - BAR / II49<br>Helmholtzstr. 18<br>01069 Dresden<br><br>Tel: +49 (0)351 463 40844<br><br><font color="000000">email: <a href="mailto:thomas.brumme@tu-dresden.de" target="_blank">thomas.brumme@tu-dresden.de</a></font></font><br></pre>
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<div id="gmail-m_4870979784934524219divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>Von:</b> users <<a href="mailto:users-bounces@lists.quantum-espresso.org" target="_blank">users-bounces@lists.quantum-espresso.org</a>>
im Auftrag von Kiran Yadav <<a href="mailto:kiranyadav0816@gmail.com" target="_blank">kiranyadav0816@gmail.com</a>><br>
<b>Gesendet:</b> Dienstag, 24. November 2020 10:45<br>
<b>An:</b> Quantum ESPRESSO users Forum<br>
<b>Betreff:</b> Re: [QE-users] QE Parallelization for Phonon Dispersion calculations</font>
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<div dir="ltr">Dear Lorenzo,
<div>Thanks a lot for the great help.</div>
<div>If possible, please suggest some reference on how to run each q-point simultaneously or do as you have suggested.</div>
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<div dir="ltr"><font face="verdana, sans-serif">Thanks & Regards,<br>
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<div dir="ltr"><font face="verdana, sans-serif">Kiran Yadav</font></div>
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<div dir="ltr" class="gmail_attr">On Tue, Nov 24, 2020 at 3:09 PM Lorenzo Paulatto <<a href="mailto:paulatz@gmail.com" target="_blank">paulatz@gmail.com</a>> wrote:<br>
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<p>Images are only used inside each q-point, if I remember correctly, so it would not matter in our question.<br>
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<p>But, you can decrease walltime much more by running each q-point simultaneously and independently using startq, startq options and a job for each. It is sufficient to use a different prefix or outdir. The data from pw can be copied or repeated, it does not
usually matter in terms of CPU time.</p>
<p>cheers<br>
</p>
On 2020-11-24 10:27, Kiran Yadav wrote:<br>
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<div>Dear Lorenzo,</div>
<div>Is there any parallelization method so that I can make images such that 20 dyn files will get distributed unequally on the equal number of processors or dyn files will get distributed equally on unequal number of processors ?</div>
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<div>Because in my case as per my observation dyn1-10 are not taking too much time, most of the time has been spent on dyn11-dyn20 generation. So, If I could run dyn 1-10 on one image and distribute remaining dyn11-20 on 3 images CPU walltime can be decreased.
Is it possible to do something like that? </div>
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<div>I tried parallelization on 256 processors (#PBS -l select=16:ncpus=16) for 10hrs using the following parallelization command</div>
<div>time -p mpirun -np $PBS_NTASKS ph.x -ni 4 -nk 4 -nt 4 -nd 16 -input <a href="http://ph.in/" target="_blank">ph.in</a> > ph.out<br>
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<div>in this case 20dyn files got distributed in 4 images i.e 5 dyn on one image. 256/4=</div>
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<div dir="ltr"><font face="verdana, sans-serif">Thanks & Regards,<br>
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<div dir="ltr"><font face="verdana, sans-serif">Kiran Yadav</font></div>
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<div><font face="verdana,
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<div dir="ltr" class="gmail_attr">On Tue, Nov 24, 2020 at 1:19 PM Lorenzo Paulatto <<a href="mailto:paulatz@gmail.com" target="_blank">paulatz@gmail.com</a>> wrote:<br>
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> I have been trying to calculate Phonon dispersion with 6*6*6 nq grid. <br>
> It generates dyn0+20 other dynamical matrices, but the time taken by <br>
> each dynamical matrix file is different for completion. I ran these <br>
> phonon dispersion calculations using parallelization, but couldn't <br>
> optimize correctly.<br>
<br>
This is normal, because different q-points have different symmetries, <br>
the code has to use different numbers of k-points.<br>
<br>
<br>
regards<br>
<br>
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