Dear Matthias,<br><br>Thank you very much for the fast reply. Even when setting EPS_DEFAULT to 10-14, I get some of these oscillations, as shown below:<br><br><div> Step Update method Time Convergence Total energy Change</div><div> ------------------------------------------------------------------------------</div><div> 1 OT DIIS 0.15E+00 5.1 0.00000073 -5301.9181906664 -5.30E+03</div><div> 2 OT DIIS 0.15E+00 2.5 0.00000029 -5301.9181922654 -1.60E-06</div><div> 3 OT DIIS 0.15E+00 2.5 0.00000005 -5301.9181886933 3.57E-06</div><div> 4 OT DIIS 0.15E+00 2.5 0.00000001 -5301.9181899089 -1.22E-06</div><div> 5 OT DIIS 0.15E+00 2.5 4.4595E-09 -5301.9181899089 -5.09E-11</div><div> 6 OT DIIS 0.15E+00 2.5 1.8983E-09 -5301.9181886941 1.21E-06</div><div> 7 OT DIIS 0.15E+00 2.5 6.8365E-10 -5301.9181899090 -1.21E-06</div><div><br></div><div> *** SCF run converged in 7 steps ***</div><div><br>I am actually wondering why the SCF cycle converges at all, despite the change in total energy of 1.21E-06 Ha between the 6th and 7th iteration.<br><br>Best regards,<br>Michael<br><br></div><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">Matthias Krack schrieb am Mittwoch, 23. Juni 2021 um 16:59:17 UTC+2:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Hi Michael<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">you can also try to reduce EPS_DEFAULT to 1.0E-12 or less for a better numerical accuracy.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">HTH<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Matthias</span><span lang="DE-CH" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Von:</span></b><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <a href data-email-masked rel="nofollow">c...@googlegroups.com</a> <<a href data-email-masked rel="nofollow">c...@googlegroups.com</a>>
<b>Im Auftrag von </b>Michael Fischer<br>
<b>Gesendet:</b> Mittwoch, 23. Juni 2021 15:34<br>
<b>An:</b> cp2k <<a href data-email-masked rel="nofollow">c...@googlegroups.com</a>><br>
<b>Betreff:</b> [CP2K:15615] Energy oscillations in vdW-DF calculations<u></u><u></u></span></p>
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<p class="MsoNormal">Dear CP2K community,<br>
<br>
I am seeing a somewhat strange behaviour in CP2K calculations using vdW-DF functionals (version 7.1): Within one SCF cycle, the calculation sometimes reaches a point where it jumps back and forth between different energy values. Such behaviour is illustrated
in a portion of a log file appended to this message. This calculation used the vdW-DF-b86r functional, but I have seen the same behaviour with other vdW-DF functionals. <br>
I should add the following points:<br>
1) The compound under consideration, a zeolite with an adsorbed molecule, contains only main group elements (Si, O, C, H, N).<br>
2) Analogous calculations using DFT-D methods (like PBE-D3) show no convergence issues whatsoever.<br>
3) A change of preconditioner (FULL_ALL/FULL_KINETIC) seems to affect the behaviour, but does not resolve the issue.<br>
<br>
I should also note that I tested the "CUTOFF" parameter within &XC &vdW_POTENTIAL &NON_LOCAL part of the input and found that it should be increased with regard to the default setting to get converged adsorption energies (I use 400 Ry).<br>
<br>
Any help or suggestions would be highly appreciated.<br>
Best regards,<br>
Michael<br>
<br>
Portion of output - oscillations start in the 8th iteration<u></u><u></u></p>
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<p class="MsoNormal"> Step Update method Time Convergence Total energy Change<u></u><u></u></p>
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<p class="MsoNormal"> ------------------------------------------------------------------------------<u></u><u></u></p>
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<p class="MsoNormal"> 1 OT DIIS 0.15E+00 5.0 0.00004571 -5301.9144127012 -5.30E+03<u></u><u></u></p>
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<p class="MsoNormal"> 2 OT DIIS 0.15E+00 2.4 0.00001858 -5301.9158989932 -1.49E-03<u></u><u></u></p>
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<p class="MsoNormal"> 3 OT DIIS 0.15E+00 2.4 0.00001214 -5301.9161596822 -2.61E-04<u></u><u></u></p>
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<p class="MsoNormal"> 4 OT DIIS 0.15E+00 2.5 0.00000142 -5301.9161913868 -3.17E-05<u></u><u></u></p>
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<p class="MsoNormal"> 5 OT DIIS 0.15E+00 2.4 0.00000043 -5301.9161930782 -1.69E-06<u></u><u></u></p>
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<p class="MsoNormal"> 6 OT DIIS 0.15E+00 2.4 0.00000011 -5301.9161943445 -1.27E-06<u></u><u></u></p>
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<p class="MsoNormal"> 7 OT DIIS 0.15E+00 2.4 0.00000005 -5301.9161967775 -2.43E-06<u></u><u></u></p>
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<p class="MsoNormal"> 8 OT DIIS 0.15E+00 2.4 0.00000001 -5301.9161955633 1.21E-06<u></u><u></u></p>
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<p class="MsoNormal"> 9 OT DIIS 0.15E+00 2.4 4.0079E-09 -5301.9161967782 -1.21E-06<u></u><u></u></p>
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<p class="MsoNormal"> 10 OT DIIS 0.15E+00 2.4 1.7554E-09 -5301.9161955634 1.21E-06<u></u><u></u></p>
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<p class="MsoNormal"> 11 OT DIIS 0.15E+00 2.4 6.2727E-10 -5301.9161967782 -1.21E-06<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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