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<p>Hi Lorenzo,</p>
<p><br>
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<p>Thanks a lot for clarifications!</p>
<p><br>
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<p></p>
<div><font style="font-size:12pt"><font style="font-family: Calibri, Helvetica, sans-serif, serif, "EmojiFont";"><font style="font-size:large">> The only way to be sure is to repeat the pw.x calculation increasing nbnd, but if pw.x did not complain
</font></font></font><em><font style="font-size:12pt"><font style="font-family: Calibri, Helvetica, sans-serif, serif, "EmojiFont";"><font style="font-size:large">during scf</font></font></font></em><font style="font-size:12pt"><font style="font-family: Calibri, Helvetica, sans-serif, serif, "EmojiFont";"><font style="font-size:large"> about
the total integrated charge being slightly off, the calculation should be ok.</font></font></font></div>
<p></p>
<p><br>
</p>
<p>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. <br>
</p>
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<p>Iurii<br>
</p>
<p><br>
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<font size="3" face="'Times New Roman', Times, serif" color="808080">--<br>
<span style="font-family:Cambria,Georgia,serif">Dr. Iurii TIMROV</span><br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Lorenzo Paulatto <lorenzo.paulatto@sorbonne-universite.fr><br>
<b>Sent:</b> Thursday, November 25, 2021 10:34:05 AM<br>
<b>To:</b> Iurii TIMROV; Quantum ESPRESSO users Forum<br>
<b>Subject:</b> Re: [QE-users] Possibly too few bands at point 2 message in DFT+U+V calculation</font>
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<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">> In the HP output file, I am getting below two messages:</font></font></font></div>
<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">> Possibly too few bands at point 2</font></font></font></div>
<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">> If this is really related to QE input file then why I do not see any such message in QE output file?</font></font></font></div>
<div class="x_gmail_default"><br>
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<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">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.</font></font></font></div>
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<div class="x_gmail_default"><br>
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">Hello Iurii, I hope you don't mind if I jump in and comment on this.</font></font></font></div>
<br>
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">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)).
</font></font></font></div>
<br>
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">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
</font></font></font><em><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">maybe</font></font></font></em><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large"> there
were not enough bands to begin with, i.e. that if there had been more bands their occupation may have been non-negligible.</font></font></font></div>
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">The only way to be sure is to repeat the pw.x calculation increasing nbnd, but if pw.x did not complain
</font></font></font><em><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">during scf</font></font></font></em><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large"> about
the total integrated charge being slightly off, the calculation should be ok.</font></font></font></div>
<br>
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">hth</font></font></font></div>
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<div><signature id="initial">Dr. Lorenzo Paulatto<br>
IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université<br>
phone: +33 (0)1 442 79822 / skype: paulatz<br>
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23-24/423 B115, 4 place Jussieu 75252 Paris CX 05</signature></div>
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<div class="gmail_quote_attribution">On Nov 25 2021, at 10:11 am, Iurii TIMROV via users <users@lists.quantum-espresso.org> wrote:</div>
<blockquote>
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<div class="x_gmail_default"><br>
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<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">> In the HP output file, I am getting below two messages:</font></font></font></div>
<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">> Possibly too few bands at point 2</font></font></font></div>
<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">> If this is really related to QE input file then why I do not see any such message in QE output file?</font></font></font></div>
<div class="x_gmail_default"><br>
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<div class="x_gmail_default">
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">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.</font></font></font></div>
</div>
<div class="x_gmail_default"><br>
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<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">> Should we set nbnd in QE input file or we can ignore it?</font></font></font></div>
<div class="x_gmail_default"><br>
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<div class="x_gmail_default">
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">If you do not specify nbnd, pw.x will automatically include only occupied states for insulators and +20% more for metals.</font></font></font></div>
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<div class="x_gmail_default"><br>
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<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:large">> Number of k-points >= 100: set verbosity='high' to print the bands.</font></font></font></div>
<div class="x_gmail_default">
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font size="4">> I do not find q verbosity tag in "hp.x input description" file instead I found iverbosity. </font></font></font></div>
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<div class="x_gmail_default"><br>
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<div class="x_gmail_default">
<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font size="4">HP prints only irreducible q points if you use symmetry.</font></font></font></div>
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<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font size="4">> Anyway, it should not affect the final U+V value as we do not see any effect of verbosity on band structure calculation. RIght?</font></font></font></div>
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<div class="x_gmail_default"><br>
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<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font size="4">Right</font></font></font></div>
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<div class="x_gmail_default"><br>
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<div class="x_gmail_default"><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif"><font size="4">> or I should set iverbosity=2 in HP input file?</font></font></font></div>
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<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif">No need. But if you want to see more info you can do that.</font></font></div>
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<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif">HTH</font></font></div>
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<div><font style="font-size:12pt"><font style="font-family:Calibri, Helvetica, sans-serif">Iurii</font></font></div>
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<div><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:12pt"><font style="font-family:Calibri, Arial, Helvetica, sans-serif"><span style="color:rgb(128, 128, 128)"><font size="3"><font style="font-family:"Times New Roman", Times, serif">--</font></font></span></font></font></font></div>
<div><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:12pt"><font style="font-family:Calibri, Arial, Helvetica, sans-serif"><span style="color:rgb(128, 128, 128)"><font size="3"><font style="font-family:"Times New Roman", Times, serif"><font style="font-family:Cambria, Georgia, serif">Dr.
Iurii TIMROV</font></font></font></span></font></font></font></div>
<div><font style="font-family:Calibri, Helvetica, sans-serif"><font style="font-size:12pt"><font style="font-family:Calibri, Arial, Helvetica, sans-serif"><span style="color:rgb(128, 128, 128)"><font size="3"><font style="font-family:"Times New Roman", Times, serif"><font style="font-family:Cambria, Georgia, serif">Senior
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<div><font style="font-size:11pt"><font style="font-family:Calibri, sans-serif"><strong>From:</strong></font></font><font style="font-size:11pt"><font style="font-family:Calibri, sans-serif"> users <users-bounces@lists.quantum-espresso.org> on behalf of Dr.
K. C. Bhamu <kcbhamu85@gmail.com></font></font></div>
<div><font style="font-size:11pt"><font style="font-family:Calibri, sans-serif"><strong>Sent:</strong></font></font><font style="font-size:11pt"><font style="font-family:Calibri, sans-serif"> Thursday, November 25, 2021 3:47:50 AM</font></font></div>
<div><font style="font-size:11pt"><font style="font-family:Calibri, sans-serif"><strong>To:</strong></font></font><font style="font-size:11pt"><font style="font-family:Calibri, sans-serif"> Quantum Espresso users Forum</font></font></div>
<div><font style="font-size:11pt"><font style="font-family:Calibri, sans-serif"><strong>Subject:</strong></font></font><font style="font-size:11pt"><font style="font-family:Calibri, sans-serif"> [QE-users] Possibly too few bands at point 2 message in DFT+U+V
calculation</font></font></div>
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<div class="gmail_default"><font style="font-size:large">Dear Dr. Timrov,</font></div>
<div class="gmail_default"><br>
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<div class="gmail_default"><font style="font-size:large">I have set verbosity = high in QE input file without specifying nbnd.</font></div>
<div class="gmail_default"><font style="font-size:large">In the HP output file, I am getting below two messages:</font></div>
<div class="gmail_default">
<ul>
<li>
<div><font style="font-size:large">Possibly too few bands at point 2</font></div>
</li></ul>
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<div class="gmail_default"><font style="font-size:large">If this is really related to QE input file then why I do not see any such message in QE output file?</font></div>
<div class="gmail_default"><font style="font-size:large">Should we set nbnd in QE input file or we can ignore it?</font></div>
<div class="gmail_default">
<ul>
<li>
<div><font style="font-size:large">Number of k-points >= 100: set verbosity='high' to print the bands.</font></div>
</li></ul>
</div>
<div class="gmail_default"><font size="4">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?</font></div>
<div class="gmail_default"><br>
</div>
<div class="gmail_default"><font size="4">Thank you for guiding me.</font></div>
<div class="gmail_default"><br>
</div>
<div class="gmail_default"><font size="4">Regards</font></div>
<div class="gmail_default"><br>
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<div class="gmail_default">
<div class="gmail_default"><font style="font-size:large">K C Bhamu</font></div>
<div class="gmail_default"><font style="font-size:large">Postdoctoral Fellow</font></div>
<div class="gmail_default"><font style="font-size:large">School of Chemical Engineering</font></div>
<div class="gmail_default"><font style="font-size:large">University of Ulsan</font></div>
<div class="gmail_default"><font style="font-size:large">South Korea</font></div>
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