PCAIRSetCFSplittingType

Sets the coarse/fine (CF) splitting algorithm used by PCAIR

Synopsis

PETSC_EXTERN PetscErrorCode PCAIRSetCFSplittingType(PC pc, CFSplittingType cf_splitting_type)

Logically Collective

Input Parameters

• pc - the PCAIR preconditioner context

• cf_splitting_type - the CF splitting algorithm, one of CF_PMISR_DDC, CF_DIAG_DOM, CF_PMIS, CF_PMIS_DIST2, CF_AGG, CF_PMIS_AGG, or CF_CR

Options Database Key

• -pc_air_cf_splitting_type (pmisr_ddc|diag_dom|pmis|pmis_dist2|agg|pmis_agg|cr) - the CF splitting algorithm; defaults to pmisr_ddc

Note

This chooses the algorithm that partitions the unknowns into coarse (C) and fine (F) points on each level; the default CF_PMISR_DDC combines a PMISR splitting with diagonal-dominance conversion and is a reasonable general-purpose choice for well-scaled PDEs. The CF_DIAG_DOM splitting enforces a given diagonal dominance ratio, and can be more robust. The CF_CR splitting uses compatible relaxation, coarsening from scratch until one application of the F-point polynomial smoothing contracts the error on the fine-fine block at a target rate. The strong threshold is used to define strong connections, the target diagonal dominance ratio, or the target CR rate, depending on the splitting chosen (see PCAIRSetStrongThreshold()).

See Also

KSP: Linear System Solvers, PCAIR, PCAIRGetCFSplittingType(), CFSplittingType, PCAIRSetStrongThreshold(), PCAIRSetMaxLubySteps()

Level

intermediate

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