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Wrap MPI_Allgatherv for NdFlattener #1897

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Merged
pcarruscag merged 3 commits into from
Jan 20, 2023
Merged

Wrap MPI_Allgatherv for NdFlattener #1897

pcarruscag merged 3 commits into from
Jan 20, 2023

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@maxaehle
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@maxaehle maxaehle commented Jan 20, 2023

Proposed Changes

Let NdFlattener use a wrapped MPI_Allgatherv function which checks the number of participating MPI ranks. If there is only one, perform a simple copy operation instead.

I hope that this fixes #1893, which I believe to be the result of a bug in MPICH. In my Ubuntu MPICH container, the [NdFlattener] test succeeds with these changes.

Related Work

#1893

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@maxaehle
NdFlattener uses wrapper for Allgatherv
a9561c5 
The wrapper performs a copy operation if there is only one MPI
rank, to avoid a potential bug in MPICH's Allgatherv
implementation.
pcarruscag
pcarruscag reviewed Jan 20, 2023
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pcarruscag
pcarruscag approved these changes Jan 20, 2023
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Thanks

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github-advanced-security bot found potential problems Jan 20, 2023
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@pcarruscag pcarruscag merged commit 16fb3a3 into develop Jan 20, 2023
@pcarruscag pcarruscag deleted the fix_allgatherv branch January 20, 2023 22:45
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@maxaehle @pcarruscag