PCGAMGSetAggressiveSquareGraph#
Use graph square, \(A^T A\), for aggressive coarsening. Coarsening is slower than the alternative (MIS-2), which is faster and uses less memory
Synopsis#
#include "petscpc.h"
PetscErrorCode PCGAMGSetAggressiveSquareGraph(PC pc, PetscBool b)
Logically Collective
Input Parameters#
pc - the preconditioner context
b - default true
Options Database Key#
-pc_gamg_aggressive_square_graph <bool,default=true> - the flag
Notes#
If b is PETSC_FALSE then MIS-k is used for aggressive coarsening, see PCGAMGMISkSetAggressive()
Squaring the matrix to perform the aggressive coarsening is slower and requires more memory than using MIS-k, but may result in a better preconditioner that converges faster.
See Also#
the Users Manual section on PCGAMG, the Users Manual section on PCMG, KSP: Linear System Solvers, PCGAMG, PCGAMGSetThreshold(), PCGAMGSetAggressiveLevels(), PCGAMGMISkSetAggressive(), PCGAMGMISkSetMinDegreeOrdering(), PCGAMGSetLowMemoryFilter()
Level#
intermediate
Location#
Examples#
Implementations#
PCGAMGSetAggressiveSquareGraph_AGG() in src/ksp/pc/impls/gamg/agg.c
Index of all PC routines
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Index of all manual pages