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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>
    </p>
    <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>
    <blockquote type="cite"
cite="mid:CAALj=363SK06S_6Rc0017==SotYDN_2KAtC5ebbf+JJ7w711OQ@mail.gmail.com">
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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>
        <div><br>
        </div>
        <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>
        <div><br>
        </div>
        <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"
            moz-do-not-send="true">ph.in</a> > ph.out<br>
        </div>
        <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>
                                            </font></div>
                                          <div dir="ltr"><font
                                              face="verdana, sans-serif">Kiran
                                              Yadav</font></div>
                                          <div dir="ltr">
                                            <div><font face="verdana,
                                                sans-serif">Research
                                                Scholar</font></div>
                                            <div><font face="verdana,
                                                sans-serif">Electronic
                                                Materials Laboratory
                                                (TX-200G)</font></div>
                                            <div><font face="verdana,
                                                sans-serif">Dept. of
                                                Materials Science &
                                                Engineering</font></div>
                                            <div><font face="verdana,
                                                sans-serif">Indian
                                                Institute of Technology,
                                                Delhi</font></div>
                                          </div>
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                                          <div><i><br>
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      <div class="gmail_quote">
        <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" moz-do-not-send="true">paulatz@gmail.com</a>>
          wrote:<br>
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          0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
          > 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>
          <br>
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      <pre class="moz-quote-pre" wrap="">_______________________________________________
Quantum ESPRESSO is supported by MaX (<a class="moz-txt-link-abbreviated" href="http://www.max-centre.eu">www.max-centre.eu</a>)
users mailing list <a class="moz-txt-link-abbreviated" href="mailto:users@lists.quantum-espresso.org">users@lists.quantum-espresso.org</a>
<a class="moz-txt-link-freetext" href="https://lists.quantum-espresso.org/mailman/listinfo/users">https://lists.quantum-espresso.org/mailman/listinfo/users</a></pre>
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