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Bug #3120

Uninitialized energy and virial contributions with PME on GPU on PME-only rank

Added by Berk Hess about 2 months ago. Updated about 1 month ago.

Status:
Resolved
Priority:
High
Assignee:
-
Category:
mdrun
Target version:
Affected version - extra info:
Affected version:
Difficulty:
uncategorized
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Description

The struct passing data from a PME-only rank is unitialized with PME on a GPU, which can give non-zero LJ reciprocal energy and virial contributions, which are added to the potential energy and virial.
Up till now we only observed non-zero contributions with the clang compiler for the CPU side code and only with release builds.
The "random" energy and virial contributions likely don't go unnoticed and with pressure coupling we would expect a run to crash after a few steps.

Associated revisions

Revision 41bcf87d (diff)
Added by Berk Hess about 2 months ago

Fix random energy and virial with PME on GPU on a PME-only rank

Missing zero initialization of never computed LJ PME energy and virial
terms with PME on the GPU could lead to random energy, virial and
pressure numbers.

The effect of this bug was that the potential and total energy could
be off (not the Coulomb mesh energy). This didn't affect sampling.
The pressure could be off, which would affect sampling when pressure
coupling is used, but likely the simulation would explode after
a few steps.

Fixes #3120

Change-Id: I309dde958f1b73e7f71f87f4f5ad016d16f8d16b

Revision 54898ee5 (diff)
Added by Berk Hess about 1 month ago

Fix random energy and virial with PME on GPU on a PME-only rank

Missing zero initialization of never computed LJ PME energy and virial
terms with PME on the GPU could lead to random energy, virial and
pressure numbers.

The effect of this bug was that the potential and total energy could
be off (not the Coulomb mesh energy). This didn't affect sampling.
The pressure could be off, which would affect sampling when pressure
coupling is used, but likely the simulation would explode after
a few steps.

Fixes #3120

Change-Id: I309dde958f1b73e7f71f87f4f5ad016d16f8d16b

History

#2 Updated by Berk Hess about 2 months ago

  • Subject changed from Unitialized energy and virial contributions with PME on GPU on PME-only rank to Uninitialized energy and virial contributions with PME on GPU on PME-only rank

#3 Updated by Berk Hess about 2 months ago

  • Status changed from Fix uploaded to Resolved

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