CLUSTER mode in LAMMPS

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Daniel Schopf

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Apr 16, 2012, 3:59:10 AM4/16/12

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Hi,

I have found a bug in the KIM implementation for LAMMPS. When checking
my model driver I noticed that there is some inconsistency when using
CLUSTER mode in LAMMPS.

When using periodic boundary conditions then LAMMPS gives you wrong
forces and energies. For testing I used a configuration
with 8 atoms in a large simulation box.

Looking into this, I found out that LAMMPS actually passes 64 atoms to
my model and sets numberContributingParticles=8. This is actually not
supported by CLUSTER mode and all 64 atoms will contribute.

If you use non-periodic boundary conditions then everything is working
as expected.

I know that CLUSTER mode is not supposed to be used with PBC but I guess
this case should give at least a warning or even an error.

Best regards,
Daniel

Ryan S. Elliott

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Apr 16, 2012, 9:13:30 AM4/16/12

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Hi Daniel,

Thanks for reporting the bug. We'll look into it...

Cheers,

Ryan Elliott

--
Ryan S. Elliott, Ph.D. and Associate Professor
Russell J. Penrose Faculty Fellow
Aerospace Engineering & Mechanics, University of Minnesota
(612) 624-2376 (626-1558 fax)
http://www.aem.umn.edu/~elliott/
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KIM Editor (http://openKIM.org)
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