Hi Jurg,<div><br /></div><div>Thank you very much for the information. Just to confirm, the "Total FORCE_EVAL (QS) energy" quantity is the correct energy to use?</div><div><br /></div><div>For this calculation, I have used an EPS_SCF of 5E-7, which is tighter than default. Are you suggesting that the discrepancy between "Total energy:" and "Total FORCE_EVAL (QS) energy" which I'm observing here means that my forces could be noisy or energy isn't well-converged? Previously, I have confirmed that the force is well-converged by modifying/increasing EPS_DEFAULT and it changes atomic forces by less than 0.01 eV/A.</div><div><br /></div><div>Best wishes,</div><div>Benjamin<br /><br /></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Monday, May 6, 2024 at 5:34:01 PM UTC+10 Jürg Hutter wrote:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi
<br>
<br>this is a problem of consistency of forces and energies. During the SCF
<br>some energy terms (especially with diagonalization) are calculated from the
<br>input density and some from the output density. Upon convergence
<br>the energy is recalculated in a consistent manner and forces are wrt this
<br>energy.
<br>However, this shouldn't matter as long as the density is sufficiently converged.
<br>In your case I would suggest to improve SCF convergence, as that will also
<br>considerably reduce the noise (or error) on your forces (good for ML).
<br>
<br>regards
<br>JH
<br>
<br>________________________________________
<br>From: <a href data-email-masked rel="nofollow">cp...@googlegroups.com</a> <<a href data-email-masked rel="nofollow">cp...@googlegroups.com</a>> on behalf of Benjamin Shi <<a href data-email-masked rel="nofollow">benjam...@gmail.com</a>>
<br>Sent: Sunday, May 5, 2024 11:56 AM
<br>To: cp2k
<br>Subject: [CP2K:20171] Different Total energy and ENERGY| Total FORCE_EVAL ( QS ) energy [a.u.]
<br>
<br>Dear CP2K developers,
<br>
<br>I am writing to enquire as to what the difference is between the energy given by "Total energy:" and "ENERGY| Total FORCE_EVAL ( QS ) energy [a.u.]:". As seen in attached output file, I'm finding a slight difference in the two energy values. Does this arise because I incorporate Fermi smearing? In the context of training machine learning potentials, which quantity would be the correct quantity to use that is consistent with the forces that are printed out?
<br>
<br>Thank you for your help,
<br>Benjamin
<br>
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<br></blockquote></div>

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