> But if nbnd was specified explicitly in the input then one should increase > nbnd and see what happens. > >
Well, pw.x just takes 20% more bands. It could not be enough, for example if you have a bunch of f-orbitals piling up around the Fermi energy, which is a typical case where you may want to use DFT+U. Double checking is always a good idea. Dr. Lorenzo Paulatto IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université phone: +33 (0)1 442 79822 / skype: paulatz http://www.impmc.upmc.fr/~paulatto/ (https://link.getmailspring.com/link/61cd862f-add7-4b6f-8ab9-afac69040...@getmailspring.com/0?redirect=http%3A%2F%2Fwww.impmc.upmc.fr%2F~paulatto%2F&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D) - https://anharmonic.github.io/ (https://link.getmailspring.com/link/61cd862f-add7-4b6f-8ab9-afac69040...@getmailspring.com/1?redirect=https%3A%2F%2Fanharmonic.github.io%2F&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D) 23-24/423 B115, 4 place Jussieu 75252 Paris CX 05 On Nov 25 2021, at 10:40 am, Iurii TIMROV <iurii.tim...@epfl.ch> wrote: > > Hi Lorenzo, > > Thanks a lot for clarifications! > > > > The only way to be sure is to repeat the pw.x calculation increasing nbnd, > > but if pw.x did not complain during scf about the total integrated charge > > being slightly off, the calculation should be ok. > > Ok. So it depends how the pw.x calculation was performed. If nbnd was not > specified explicitly in the input then I guess all should be fine because > pw.x determines nbnd automatically. But if nbnd was specified explicitly in > the input then one should increase nbnd and see what happens. > > Iurii > > -- > Dr. Iurii TIMROV > Senior Research Scientist > > Theory and Simulation of Materials (THEOS) > Swiss Federal Institute of Technology Lausanne (EPFL) > > CH-1015 Lausanne, Switzerland > +41 21 69 34 881 > > http://people.epfl.ch/265334 > (https://link.getmailspring.com/link/61cd862f-add7-4b6f-8ab9-afac69040...@getmailspring.com/2?redirect=http%3A%2F%2Fpeople.epfl.ch%2F265334&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D) > > > > > > From: Lorenzo Paulatto <lorenzo.paula...@sorbonne-universite.fr> > Sent: Thursday, November 25, 2021 10:34:05 AM > To: Iurii TIMROV; Quantum ESPRESSO users Forum > Subject: Re: [QE-users] Possibly too few bands at point 2 message in DFT+U+V > calculation > > > > > > In the HP output file, I am getting below two messages: > > > Possibly too few bands at point 2 > > > If this is really related to QE input file then why I do not see any such > > > message in QE output file? > > > > I am not totally sure but I presume that this might be related to the fact > > that you use too many cores for your system. I think no need to worry about > > this. > > Hello Iurii, I hope you don't mind if I jump in and comment on this. > The premise is that the Sternheimer equation of DFPT can be solved using only > the valence states, which is it greatest advantage w.r.t standard QM > perturbation theory, which requires a sum over the entire spectrum of virtual > states. In the case of metal, where electronic occupation can be fractionary, > the Sternheimer equation can be adjusted to keep this into account (PRB 51, > 6773 (1995)). > The completely empty states are still not required and the linear-response > solver tries to throw them away to save time. The algorithm only includes > states up to a ~3 sigmas (the smearing width) up from the Fermi energy. If > during this search the algorithm runs out of bands before reaching the > threshold, its warns that maybe there were not enough bands to begin with, > i.e. that if there had been more bands their occupation may have been > non-negligible. > The only way to be sure is to repeat the pw.x calculation increasing nbnd, > but if pw.x did not complain during scf about the total integrated charge > being slightly off, the calculation should be ok. > > hth > > Dr. Lorenzo Paulatto > IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université > phone: +33 (0)1 442 79822 / skype: paulatz > http://www.impmc.upmc.fr/~paulatto/ > (https://link.getmailspring.com/link/61cd862f-add7-4b6f-8ab9-afac69040...@getmailspring.com/3?redirect=https%3A%2F%2Flink.getmailspring.com%2Flink%2F30EFE2C7-FCF2-4279-A941-421485ED269D%40getmailspring.com%2F0%3Fredirect%3Dhttp%253A%252F%252Fwww.impmc.upmc.fr%252F~paulatto%252F%26recipient%3DaXVyaWkudGltcm92QGVwZmwuY2g%253D&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D) > - https://anharmonic.github.io/ > (https://link.getmailspring.com/link/61cd862f-add7-4b6f-8ab9-afac69040...@getmailspring.com/4?redirect=https%3A%2F%2Flink.getmailspring.com%2Flink%2F30EFE2C7-FCF2-4279-A941-421485ED269D%40getmailspring.com%2F1%3Fredirect%3Dhttps%253A%252F%252Fanharmonic.github.io%252F%26recipient%3DaXVyaWkudGltcm92QGVwZmwuY2g%253D&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D) > 23-24/423 B115, 4 place Jussieu 75252 Paris CX 05 > > > > > > > > > > > > > > > On Nov 25 2021, at 10:11 am, Iurii TIMROV via users > <users@lists.quantum-espresso.org> wrote: > > > > > > > > > In the HP output file, I am getting below two messages: > > > Possibly too few bands at point 2 > > > If this is really related to QE input file then why I do not see any such > > > message in QE output file? > > > > I am not totally sure but I presume that this might be related to the fact > > that you use too many cores for your system. I think no need to worry about > > this. > > > > > Should we set nbnd in QE input file or we can ignore it? > > > > If you do not specify nbnd, pw.x will automatically include only occupied > > states for insulators and +20% more for metals. > > > > > Number of k-points >= 100: set verbosity='high' to print the bands. > > > I do not find q verbosity tag in "hp.x input description" file instead I > > > found iverbosity. > > > > > > HP prints only irreducible q points if you use symmetry. > > > > > Anyway, it should not affect the final U+V value as we do not see any > > > effect of verbosity on band structure calculation. RIght? > > > > Right > > > > > or I should set iverbosity=2 in HP input file? > > > > No need. But if you want to see more info you can do that. > > > > HTH > > > > Iurii > > > > -- > > Dr. Iurii TIMROV > > Senior Research Scientist > > > > Theory and Simulation of Materials (THEOS) > > Swiss Federal Institute of Technology Lausanne (EPFL) > > > > CH-1015 Lausanne, Switzerland > > +41 21 69 34 881 > > > > http://people.epfl.ch/265334 > > (https://link.getmailspring.com/link/61cd862f-add7-4b6f-8ab9-afac69040...@getmailspring.com/5?redirect=https%3A%2F%2Flink.getmailspring.com%2Flink%2F30EFE2C7-FCF2-4279-A941-421485ED269D%40getmailspring.com%2F2%3Fredirect%3Dhttp%253A%252F%252Fpeople.epfl.ch%252F265334%26recipient%3DaXVyaWkudGltcm92QGVwZmwuY2g%253D&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D) > > > > > > > > > > > > From: users <users-boun...@lists.quantum-espresso.org> on behalf of Dr. K. > > C. Bhamu <kcbham...@gmail.com> > > Sent: Thursday, November 25, 2021 3:47:50 AM > > To: Quantum Espresso users Forum > > Subject: [QE-users] Possibly too few bands at point 2 message in DFT+U+V > > calculation > > > > > > Dear Dr. Timrov, > > > > I have set verbosity = high in QE input file without specifying nbnd. > > In the HP output file, I am getting below two messages: > > Possibly too few bands at point 2 > > > > > > > > If this is really related to QE input file then why I do not see any such > > message in QE output file? > > Should we set nbnd in QE input file or we can ignore it? > > Number of k-points >= 100: set verbosity='high' to print the bands. > > > > > > > > I do not find q verbosity tag in "hp.x input description" file instead I > > found iverbosity. Anyway, it should not affect the final U+V value as we do > > not see any effect of verbosity on band structure calculation. RIght? or I > > should set iverbosity=2 in HP input file? > > > > Thank you for guiding me. > > > > Regards > > > > K C Bhamu > > Postdoctoral Fellow > > School of Chemical Engineering > > University of Ulsan > > South Korea > > > > > > > > > > > > _______________________________________________ > > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > > users mailing list users@lists.quantum-espresso.org > > https://lists.quantum-espresso.org/mailman/listinfo/users > >
_______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users
