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Hi,<br>
did this issue ever get resolved/answered? I would also be very
interested in a solution/explanation of the behavior. <br>
<br>
I also get relaxations where individual forces are higher than the
threshold, without the line stating that "SCF correction compared to
forces is large", in case that would be a reason here. Also happens
in regular "relax" calculations.<br>
<br>
Thanks so much,<br>
Florian<br>
<br>
--<br>
Florian Brown-Altvater<br>
PhD Candidate<br>
Neaton group<br>
UC Berkeley/LBNL<br>
<br>
<div class="moz-cite-prefix">Am 08.04.2015 um 12:07 schrieb Tianli
Feng:<br>
</div>
<blockquote
cite="mid:CAAY=65OAr5UEmQd5q_eEV_92LjTMFWByMq9vaiYgy9=ipDgEWg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>Dear All,</div>
<div><br>
</div>
<div>I would really appreciate if anyone can help to explain a
output in relaxing a structure. I used vc-relax to relax a
lattice with forc_conv_thr set as 1.0D-9. After 44 steps, the
results converge as following:</div>
<div><br>
</div>
<div>
<div> Forces acting on atoms (Ry/au):</div>
<div><br>
</div>
<div> atom 1 type 1 force = 0.00000638
0.00000000 0.00000092</div>
<div> atom 2 type 1 force = 0.00000602
0.00000000 0.00000671</div>
<div> atom 3 type 1 force = -0.00000074
0.00000000 0.00000243</div>
<div> atom 4 type 1 force = 0.00000358
0.00000000 -0.00000082</div>
<div> atom 5 type 2 force = -0.00000821
0.00000000 -0.00000732</div>
<div> atom 6 type 2 force = -0.00000635
0.00000000 -0.00000202</div>
<div> atom 7 type 2 force = 0.00000337
0.00000000 -0.00000058</div>
<div> atom 8 type 2 force = -0.00000406
0.00000000 0.00000068</div>
<div><br>
</div>
<div> Total force = 0.000018 Total SCF correction
= 0.000002</div>
<div> SCF correction compared to forces is large: reduce
conv_thr to get better values</div>
</div>
<div><br>
</div>
<div> bfgs converged in 44 scf cycles and 43 bfgs steps</div>
<div> (criteria: energy < 1.0E-04, force < 1.0E-09,
cell < 5.0E-01)</div>
<div><br>
</div>
<div>The last line says the relaxation converges with force
<1.0E-9, but I saw the forces acting on each atom are not
smaller than 1e-9. Does anyone has experience on relaxing a
lattice and know what is happening? Many thanks!!</div>
<div><br>
</div>
<div>Sincerely,</div>
<div>
<div class="gmail_signature">
<div dir="ltr">Best wishes,
<div>Tianli</div>
<div>------------</div>
<div>Tianli Feng</div>
<div>Mechanical Engineering, Purdue University</div>
<div>---The truth is not what you see, but what it is.</div>
</div>
</div>
</div>
</div>
<br>
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