<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Hi,<br>
<br>
I noticed the following mdrun (version 2020) warning in a run with
dispersion corrections switched on (dispcorr = EnerPres):<br>
<br>
WARNING: There are no atom pairs for dispersion correction<br>
<br>
accordingly, the Disper. corr. contribution is 0.00000e+00 in that
simulation.<br>
<br>
In contrast, the same tpr does not trigger this warning with
gromacs2018 or 2019, and the expected Disper. corr. contribution is
found in the output (for this particular run -8.67338e+03 at step
0).<br>
<br>
A comparison between the 2019 and 2020 versions suggests this to be
connected with the variables npair, npair_ij, iCount and jCount in
dispersioncorrection.cpp having switched from int64_t in 2019 to int
in version 2020. Indeed, monitoring these variables showed these to
turn negative, suggesting an int overflow. Switching these variables
back to int64_t as in the attached dispersioncorrection.cpp gives
back the expected, non-zero dispersion correction.<br>
<br>
best,<br>
<br>
Bert<br>
<br>
<div class="moz-signature">
______________________________________<br>
Prof. Bert de Groot, Ph.D.<br>
<br>
Max Planck Institute for Biophysical Chemistry<br>
Computational biomolecular dynamics group<br>
Am Fassberg 11<br>
37077 Goettingen, Germany<br>
tel: +49-551-2012308, fax: +49-551-2012302<br>
<a href="http://www.mpibpc.mpg.de/groups/de_groot">http://www.mpibpc.mpg.de/groups/de_groot</a></div>
</body>
</html>