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<br>Dear Gabrielle and Lorenzo,<div><br></div><div>Thanks very much for the links. I will be having a look at them.</div><div><br></div><div><br></div><div>Regards</div><div><br></div><div><br></div><div>Elie<br><div><div id="SkyDrivePlaceholder"></div><hr id="stopSpelling">From: gabriele.sclauzero@epfl.ch<br>Subject: Re: [Pw_forum] phonon calculations in a spercell of 100 atoms<br>Date: Mon, 13 Feb 2012 17:41:13 +0100<br>To: elie.moujaes@hotmail.co.uk<br><br>
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<meta name="Generator" content="Microsoft SafeHTML">Dear Elie,<div><br></div><div> you might want to have a look at Dario Alfè's webpage</div><div><a href="http://www.homepages.ucl.ac.uk/~ucfbdxa/phon/" target="_blank">http://www.homepages.ucl.ac.uk/~ucfbdxa/phon/</a></div><div>He has a code that should do what you need.</div><div><br></div><div>HTH</div><div><br></div><div>GS</div><div><br></div><div><br></div><div><div><div>Il giorno 13/feb/2012, alle ore 17.24, Elie M ha scritto:</div><br class="ecxApple-interchange-newline"><blockquote><div class="ecxhmmessage" style="font-size:10pt;font-family:Tahoma"><div dir="ltr">Thanks for your reply. Any reference to the finite displacement method for phonon calculations using QE?<div><br></div><div><br></div><div>Thanks again</div><div><br></div><div>Elie<br><br><div><div id="ecxSkyDrivePlaceholder"></div>> To:<span class="ecxApple-converted-space"> </span><a href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a><br>> Date: Mon, 13 Feb 2012 16:41:04 +0100<br>> From:<span class="ecxApple-converted-space"> </span><a href="mailto:Lorenzo.Paulatto@impmc.upmc.fr">Lorenzo.Paulatto@impmc.upmc.fr</a><br>> Subject: Re: [Pw_forum] phonon calculations in a spercell of 100 atoms<br>><span class="ecxApple-converted-space"> </span><br>> On Mon, 13 Feb 2012 16:36:55 +0100, Elie M <<a href="mailto:elie.moujaes@hotmail.co.uk">elie.moujaes@hotmail.co.uk</a>><span class="ecxApple-converted-space"> </span><br>> wrote:<br>> > Dear all,<br>> > I have two questions:<br>> > (1) I am running phonon calculations on a system of 100 atoms and only<span class="ecxApple-converted-space"> </span><br>> > at the Gamma point! It is really taking a lot of time. It is running in<span class="ecxApple-converted-space"> </span><br>> > the parallel computing mode with a total of 16 processors on 2 nodes and<span class="ecxApple-converted-space"> </span><br>> > still is going slow. Is there a way to speed up things? and is there a<span class="ecxApple-converted-space"> </span><br>> > way to do the whole phonon dispersion in lesser time?<br>><span class="ecxApple-converted-space"> </span><br>> Do not use a supercell? Seriously, phonon calculations are expensive, with<span class="ecxApple-converted-space"> </span><br>> many atoms they are extremely expensive. If you only need the phonons at<span class="ecxApple-converted-space"> </span><br>> the gamma point, it may be faster to get them by finite displacement,<span class="ecxApple-converted-space"> </span><br>> doing 3*nat pw.x ground state calculations.<br>><span class="ecxApple-converted-space"> </span><br>> > (2) If only the phonon frequencies at the Gamma point were calculated ,<span class="ecxApple-converted-space"> </span><br>> > I was wondering what kind of information about the system can one get?<br>> > Thanks<br>><span class="ecxApple-converted-space"> </span><br>> If the supercell is large enough, all the information you need.<br>><span class="ecxApple-converted-space"> </span><br>> bests<br>><span class="ecxApple-converted-space"> </span><br>><span class="ecxApple-converted-space"> </span><br>> --<span class="ecxApple-converted-space"> </span><br>> Lorenzo Paulatto IdR @ IMPMC/CNRS & Université Paris 6<br>> phone: <span class="skype_pnh_print_container_1329150800">+33 (0)1 44275 084</span><span class="skype_pnh_container" dir="ltr" tabindex="-1"><span class="skype_pnh_mark"> begin_of_the_skype_highlighting</span> <span class="skype_pnh_highlighting_inactive_common" dir="ltr" skypeaction="skype_dropdown" title="Call this phone number in France with Skype: +33144275084"><span class="skype_pnh_left_span" skypeaction="skype_dropdown" title="Skype actions"> </span><span class="skype_pnh_dropart_span" skypeaction="skype_dropdown" title="Skype actions"><span class="skype_pnh_dropart_flag_span" skypeaction="skype_dropdown" style="background-position: -1949px 1px !important; "> </span> </span><span class="skype_pnh_textarea_span"><span class="skype_pnh_text_span">+33 (0)1 44275 084</span></span><span class="skype_pnh_right_span"> </span></span> <span class="skype_pnh_mark">end_of_the_skype_highlighting</span></span> / skype: paulatz<br>> www:<span class="ecxApple-converted-space"> </span><a href="http://www-int.impmc.upmc.fr/~paulatto/" target="_blank">http://www-int.impmc.upmc.fr/~paulatto/</a><br>> mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05<br>> _______________________________________________<br>> Pw_forum mailing list<br>><span class="ecxApple-converted-space"> </span><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>><span class="ecxApple-converted-space"> </span><a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br></div></div></div>_______________________________________________<br>Pw_forum mailing list<br><a href="mailto:Pw_forum@pwscf.org">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></div></blockquote></div><br><div>
<span class="ecxApple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-align:auto;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px"><span class="ecxApple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px"><span class="ecxApple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px"><div style="word-wrap:break-word"><span class="ecxApple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px"><div style="word-wrap:break-word"><span class="ecxApple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px"><div style="word-wrap:break-word"><span class="ecxApple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px"><div style="word-wrap:break-word"><span class="ecxApple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px"><div style="word-wrap:break-word"><div><span class="ecxApple-style-span" style="color:rgb(126, 126, 126);font-size:16px;font-style:italic"><br class="ecxApple-interchange-newline">§ Gabriele Sclauzero, EPFL SB ITP CSEA</span></div><div><font class="ecxApple-style-span" color="#7E7E7E"><i> PH H2 462, Station 3, CH-1015 Lausanne</i></font></div></div></span><br class="ecxApple-interchange-newline"></div></span><br class="ecxApple-interchange-newline"></div></span><br class="ecxApple-interchange-newline"></div></span><br class="ecxApple-interchange-newline"></div></span><br class="ecxApple-interchange-newline"></span><br class="ecxApple-interchange-newline"></span>
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