PCAIRSetProcessorAgglom

Sets whether PCAIR uses a graph partitioner to repartition coarse grids and reduce the number of active MPI ranks

Synopsis

PETSC_EXTERN PetscErrorCode PCAIRSetProcessorAgglom(PC pc, PetscBool input_bool)

Logically Collective

Input Parameters

• pc - the PCAIR preconditioner context

• input_bool - PETSC_TRUE to repartition the coarse grids onto fewer MPI ranks as the hierarchy coarsens

Options Database Key

• -pc_air_processor_agglom (true|false) - use a graph partitioner to repartition coarse grids and reduce the number of active MPI ranks; defaults to true

Note

Processor agglomeration reduces the number of active MPI ranks by PCAIRSetProcessorAgglomFactor() whenever the local to non-local nonzero ratio drops below PCAIRSetProcessorAgglomRatio(), or the average number of equations per rank drops below PCAIRSetProcessEqLimit(); it is only performed where necessary, not on every level, and the entire hierarchy remains on the original communicator.

See Also

KSP: Linear System Solvers, PCAIR, PCAIRGetProcessorAgglom(), PCAIRSetProcessorAgglomRatio(), PCAIRSetProcessorAgglomFactor(), PCAIRSetProcessEqLimit()

Level

advanced

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Index of all manual pages