<span style="font-family:Arial">I need to clarify this situation after Huiqun's response:</span><div><span style="font-family:Arial"><br></span></div><div><span style="font-family:Arial">"Siesta+PHON: 520 sec@8CPU" was for two displacement calculations in total. If you have 16 cpu, you can </span><div>
<font class="Apple-style-span" face="Arial">run 2 displacement calculation at the same time. This reduces 520 to 260.</font></div><div><font class="Apple-style-span" face="Arial"><br></font></div><div><font class="Apple-style-span" face="Arial">After this post, you and me learned that it is also possible to reduce 328 with q_point splitting.....</font></div>
<div><font class="Apple-style-span" face="Arial"><br></font></div><div><font class="Apple-style-span" face="Arial">You can examine my files at <a href="http://unam.bilkent.edu.tr/mt2/random/pw_forum/">http://unam.bilkent.edu.tr/mt2/random/pw_forum/</a></font></div>
<div><font class="Apple-style-span" face="Arial"><br></font>
<br><div class="gmail_quote">On Mon, Aug 16, 2010 at 11:45 AM, Huiqun Zhou <span dir="ltr"><<a href="mailto:hqzhou@nju.edu.cn" target="_blank">hqzhou@nju.edu.cn</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#ffffff">
<div><font size="2" face="Arial">Mehmet,</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">Hope you are the same person who posted a very good
tutorial on phonon calculation via</font></div>
<div><font size="2" face="Arial">small displacement method (SDM) and DFPT at Siesta
forum.</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">Interestingly, I noticed that in your tutorial DFPT
(PW+PH: 328 <a href="mailto:sec@8CPU" target="_blank">sec@8CPU</a>) was much faster
</font></div>
<div><font size="2" face="Arial">than SDM </font><font size="2" face="Arial">(Siesta+PHON: 520 <a href="mailto:sec@8CPU" target="_blank">sec@8CPU</a>, VASP+PHON:
1674 <a href="mailto:sec@16CPU" target="_blank">sec@16CPU</a>) for </font><font size="2" face="Arial">the case </font></div>
<div><font size="2" face="Arial">of graphene, at least by the criteria of
getting identical phonon dispersion relation. So, your </font></div>
<div><font size="2" face="Arial">current recommendation means that was just a
individual case for </font><font size="2" face="Arial">you, right? </font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">My feel (no </font><font size="2" face="Arial">concret numbers) with qe shows that for the previous version of qe
(before 4.0 </font></div>
<div><font size="2" face="Arial">or </font><font size="2" face="Arial">earllier?) </font><font size="2" face="Arial">PW+PH was
</font><font size="2" face="Arial">somewhat slower than PW+PHON, but the
situation is reversed </font></div>
<div><font size="2" face="Arial">with recent </font><font size="2" face="Arial">versions
of qe. </font> </div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">If you have further examples, please share with
us.</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">Thank you in advance!</font></div>
<div><font size="2" face="Arial"></font> </div><font color="#888888">
<div><font size="2" face="Arial">huiqun zhou</font></div>
<div><font size="2" face="Arial">@earth sciences, nanjing university,
china</font></div>
<div> </div>
</font><blockquote style="border-left:#000000 2px solid;padding-left:5px;padding-right:0px;margin-left:5px;margin-right:0px"><div><div></div><div>
<div style="font:10pt arial">----- Original Message ----- </div>
<div style="font:10pt arial;background:#e4e4e4"><b>From:</b>
<a title="metokal@gmail.com" href="mailto:metokal@gmail.com" target="_blank">Mehmet Topsakal</a>
</div>
<div style="font:10pt arial"><b>To:</b> <a title="pw_forum@pwscf.org" href="mailto:pw_forum@pwscf.org" target="_blank">PWSCF Forum</a> </div>
<div style="font:10pt arial"><b>Sent:</b> Sunday, August 15, 2010 3:52
PM</div>
<div style="font:10pt arial"><b>Subject:</b> Re: [Pw_forum] Speeding up the
calculations</div>
<div><font size="2" face="Arial"></font><br></div>Dear Bipul,
<div><font size="2" face="Arial"></font><br></div>
<div>You can try Small Displacement Method ( see <a href="http://www.homepages.ucl.ac.uk/~ucfbdxa/" target="_blank">http://www.homepages.ucl.ac.uk/~ucfbdxa/</a> )
which has different idea than DFPT.</div>
<div>It requires you to make 2 displacement in a supercell and calculate the
forces with single scf. You can run scf's at the same time. </div>
<div>For example, you need to calculate the forces in 5x5x1 graphene supercell
having 50 carbon atoms for 2 displacemet.</div>
<div><font size="2" face="Arial"></font><font size="2" face="Arial"></font><br></div>
<div>BUT you cannot observe LO-TO splitting in polar materials (such as
honeycomb monolayer ZnO) by using SDM.</div>
<div><font size="2" face="Arial"></font><font size="2" face="Arial"></font><font size="2" face="Arial"></font><font size="2" face="Arial"></font><br></div>
<div>Regards.
</div>
<div><font size="2" face="Arial"></font><font size="2" face="Arial"></font><br>
<div class="gmail_quote">On Sat, Aug 14, 2010 at 9:44 PM, Bipul Rakshit <span dir="ltr"><<a href="mailto:bipulrr@gmail.com" target="_blank">bipulrr@gmail.com</a>></span> wrote:<br>
<blockquote style="border-left:#ccc 1px solid;margin:0px 0px 0px 0.8ex;padding-left:1ex" class="gmail_quote">Hi PWSCF user,<br>I am mainly doing Phonon calculation,
which generally is time consuming ( even in parallel). I just want to know
if there is any possible way to speed up the calculations. i.e. by
installing certain libraries or so. Or using some appropirate
methods<br><br>The machine had many nodes, and each nodes have 8/16
processors. Some of the other details of the machines are as follows:<br><br clear="all"> Intel(R) Xeon(R) CPU E5345 @ 2.33GHz, 64
bit<br>4GB RAM<br><br>compiler: mpif90 and icc<br><br>Thanks<br><font color="#888888">-- <br>Bipul Rakshit<br>Research Fellow<br>S N Bose Centre for
Basic Sciences,<br>Salt Lake,<br>Kolkata 700
098<br>India<br></font><br>_______________________________________________<br>Pw_forum
mailing list<br><a href="mailto:Pw_forum@pwscf.org" target="_blank">Pw_forum@pwscf.org</a><br><a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
<br></blockquote></div><br><br clear="all"><br>-- <br><br>Mehmet Topsakal (Ph.D.
Student)<br>UNAM-Institute of Materials Science and Nanotechnology.
<br>Bilkent University. 06800 Bilkent, Ankara/Türkiye<br>Tel: 0090 312 290
3527 ; Fax: 0090 312 266 4365<br>UNAM-web : <a href="http://www.nano.org.tr" target="_blank">www.nano.org.tr</a><br><br></div>
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<br></blockquote></div><br><br clear="all"><br>-- <br><br>Mehmet Topsakal (Ph.D. Student)<br>UNAM-Institute of Materials Science and Nanotechnology. <br>Bilkent University. 06800 Bilkent, Ankara/Türkiye<br>Tel: 0090 312 290 3527 ; Fax: 0090 312 266 4365<br>
UNAM-web : <a href="http://www.nano.org.tr" target="_blank">www.nano.org.tr</a><br><br>
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