<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hello,<div class=""><br class=""></div><div class="">As I understand from my small experience, PBE0 (or hybrids in general) is not just a question of time but also of memory. So it is better to run these calculations on supercomputers.</div><div class="">From PBE to PBE0 requires 10 to 1000 times more CPU depending on the system. If for a given system you can use 250 k-points for a SCF calculation with a GGA, you will be limited to say 30-50 k-points (perhaps even less) with a hybrid.</div><div class=""><br class=""></div><div class="">If I am correct and if possible for you, I suggest you use the hybrid HSE functional, which is based on the range-separated Exx potential evaluation, as this may save you a lot of CPU time (I am not sure for the memory usage).</div><div class=""><br class=""></div><div class="">Best,</div><div class=""><div class="">
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line-height: 22px;">Professor in computational materials - DEPARTMENT OF CHEMISTRY</em></div><div class=""><div class="" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; -webkit-text-stroke-width: 0px; font-family: Tahoma, Verdana, Arial, Helvetica, sans-serif; font-size: 15px; line-height: 22px;"><span class="" style="font-size: 11px; font-family: verdana;">University of Aix-Marseille </span><span class="" style="font-size: 11px; font-family: verdana;">- Avenue Escadrille Normandie Niemen - F-13013 Marseille - FRANCE</span></div><div class="" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; -webkit-text-stroke-width: 0px; font-family: Tahoma, Verdana, Arial, Helvetica, sans-serif; font-size: 15px; line-height: 22px;"><span class="" style="font-size: 11px; font-family: verdana;">Tél: +33(0)4 13 55 18 10 - Fax : +33(0)4 13 55 18 50</span></div><div class="" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; -webkit-text-stroke-width: 0px;"><font face="verdana" class=""><span class="" style="font-size: 12px; line-height: 22px;">Email : </span></font><font color="#22bbea" face="verdana" class=""><span style="font-size: 12px; line-height: 20px;" class=""><a href="mailto:pascal.boulet@univ-amu.fr" class="">pascal.boulet@univ-amu.fr</a></span></font></div><div class="" style="font-size: 14px;"><br class=""></div></div></div></div></div><br class="Apple-interchange-newline"></div></div></div></div></div><div><br class=""><blockquote type="cite" class=""><div class="">Le 22 nov. 2020 à 10:32, Husak Michal <<a href="mailto:Michal.Husak@vscht.cz" class="">Michal.Husak@vscht.cz</a>> a écrit :</div><br class="Apple-interchange-newline"><div class=""><div class="">I would like to ask what is the typical time difference between running PBE and<br class=""><br class="">and the hybrid PBE0 ...<br class=""><br class=""><br class="">Using CASTEP the PBE0 takes typically 200-1000 x more time than PBE ...<br class=""><br class="">This is OK , I run CASTEP on a 1000 node supercomputer and work is done in a few<br class=""><br class="">days typically ...<br class=""><br class=""><br class="">I had run PBE and PBE0 scf on super simple system (Al generated by Material Cloud www, diamond generated by me) ...<br class=""><br class="">I run in MP mode on 4 core CPU system ...<br class=""><br class="">PBE - 7.5 second<br class=""><br class="">PBE0 - run 24 hours and not yet finished<br class=""><br class=""><br class="">PBE0 on the target molecule (alanine) crashed immediately with segmentation failure ...<br class=""><br class=""><br class="">Do I something wrong, is there some magic in setting hybrid functional or do i relay need a supercomputer ? I believed I can just add PBE0 request to tested PBE setup ...<br class=""><br class="">Can anybody send me a working sample PBE0 calculation setup for small organic molecular crystal ?<br class=""><br class=""><br class="">Michal Husak<br class=""><br class="">UCT Prague<br class="">_______________________________________________<br class="">Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu" class="">www.max-centre.eu</a>)<br class="">users mailing list <a href="mailto:users@lists.quantum-espresso.org" class="">users@lists.quantum-espresso.org</a><br class=""><a href="https://lists.quantum-espresso.org/mailman/listinfo/users" class="">https://lists.quantum-espresso.org/mailman/listinfo/users</a><br class=""></div></div></blockquote></div><br class=""></div></body></html>