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Dear Zhao,</div>
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Which type of Hubbard projectors are you using for PBE+U calculations? Since the calculation of Hubbard forces and stresses takes a lot of time, then most likely you are using "ortho-atomic" Hubbard projectors. It is well known that the calculations of Hubbard
forces and stresses are slow when using this type of projectors. You can check the paper where it is explained why this is so:
<a href="https://journals.aps.org/prb/abstract/10.1103/PhysRevB.102.235159" id="LPlnk417628">
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.102.235159</a></div>
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Greetings,</div>
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Iurii</div>
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Dr. Iurii TIMROV</div>
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Tenure-track scientist</div>
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Laboratory for Materials Simulations (LMS)</div>
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Paul Scherrer Institut (PSI)</div>
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CH-5232 Villigen, Switzerland</div>
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+41 56 310 62 14</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> users <users-bounces@lists.quantum-espresso.org> on behalf of Zhao Yi-Feng <summitcheesemoon@outlook.com><br>
<b>Sent:</b> Saturday, May 10, 2025 08:15<br>
<b>To:</b> users@lists.quantum-espresso.org <users@lists.quantum-espresso.org><br>
<b>Subject:</b> [QE-users] The long time takes in calculation of Computing stress and pressure during vc-relax</font>
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Dear quantum-espresso developer and user,</div>
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I am using quantum-espresso to do the cell relaxation with vc-relax. The system is a supercell that contains 96 spin-polarized atoms (AFM) using PBE+U. It is fast for the first SCF calculation, which costs about 30 minutes to converge. However, it takes about
3.5 hours to calculate the stress (Cartesian axis) and pressure. I am not sure what happened to this issue. Could anyone help me with this? Thank you</div>
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Best regards,</div>
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Zhao</div>
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