It works when I change NGRIDS from 4 to 6 and the cost will reduce ~15%.<div><br></div><div>Best,</div><div>Ke </div><div><br><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">在2021年4月1日星期四 UTC+8 下午10:22:29...@gmail.com> 写道：<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Dear Prof. Juerg Hutter,<div><br></div><div>Thank you very much for your suggestions.</div><div>Let me test.</div><div><br></div><div>Best,</div><div>Ke </div><div><br><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">在2021年4月1日星期四 UTC+8 下午8:25:48<jgh> 写道：<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>without seeing the timings I will have to guess:
<br>the increase is coming from more time needed for
<br>1) libxc
<br>2) FFT
<br>3) collocate/integrate
<br>
<br>you can try to set NGRIDS in
<br>CP2K_INPUT / FORCE_EVAL / DFT / MGRID
<br>to a higher value (e.g. 6). That should help with 3)
<br>
<br>Another solution might be to work with GAPW and a lower cutoff,
<br>but that needs testing.
<br>
<br>regards
<br>
<br>Juerg Hutter
<br>--------------------------------------------------------------
<br>Juerg Hutter Phone : <a href="tel:+41%2044%20635%2044%2091" value="+41446354491" rel="nofollow" target="_blank">++41 44 635 4491</a>
<br>Institut für Chemie C FAX : <a href="tel:+41%2044%20635%2068%2038" value="+41446356838" rel="nofollow" target="_blank">++41 44 635 6838</a>
<br>Universität Zürich E-mail: <a rel="nofollow">h...@chem.uzh.ch</a>
<br>Winterthurerstrasse 190
<br>CH-8057 Zürich, Switzerland
<br>---------------------------------------------------------------
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<br>Date: 04/01/2021 04:59AM
<br>Subject: [CP2K:15056] The calculation speed of SCAN
<br>
<br>Dear all,
<br>
<br>Now I am calculation bulk water using SCAN (BOMD). According to the literature, the energy cutoff of SCAN is 1200 Ry, which is much higher than PBE+D3 (500 Ry).
<br>
<br>My system is 64 water molecules in a cubic box.
<br>Using 24 CPUs, the speed of SCAN is ~ 50 s/step that is much slower than PBE+D3 (~ 9 s/step). I have experience on SCAN using VASP that won’t cost much more time than PBE.
<br>
<br>Can anyone share the experience on SCAN, especially for the calculation speed and acceleration of calculation?
<br>
<br>The attachment is my input file.
<br>
<br>Best,
<br>Ke
<br>
<br>
<br>
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<br>[attachment "water.inp" removed by Jürg Hutter/at/UZH]
<br></blockquote></div></blockquote></div>