PCAIRSetProcessorAgglomFactor

Sets the factor by which PCAIR reduces the number of active MPI ranks each time processor agglomeration occurs

Synopsis

PETSC_EXTERN PetscErrorCode PCAIRSetProcessorAgglomFactor(PC pc, PetscInt input_int)

Logically Collective

Input Parameters

• pc - the PCAIR preconditioner context

• input_int - the factor by which to reduce the number of active MPI ranks

Options Database Key

• -pc_air_processor_agglom_factor factor - the factor by which to reduce the number of active MPI ranks; defaults to 2

Note

Only relevant when processor agglomeration is enabled (see PCAIRSetProcessorAgglom()); each time a level is agglomerated the number of active MPI ranks is divided by this factor. A larger factor agglomerates onto fewer ranks each step, reducing communication at the cost of more work per remaining rank.

See Also

KSP: Linear System Solvers, PCAIR, PCAIRGetProcessorAgglomFactor(), PCAIRSetProcessorAgglom(), PCAIRSetProcessorAgglomRatio()

Level

advanced

Index of all PC routines
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Index of all manual pages