Wrap MPI_Allgatherv for NdFlattener#1897
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pcarruscag merged 3 commits intodevelopfrom Jan 20, 2023
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The wrapper performs a copy operation if there is only one MPI rank, to avoid a potential bug in MPICH's Allgatherv implementation.
pcarruscag
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Jan 20, 2023
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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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