PCGAMGSetThresholdScale

Relative threshold reduction at each level

Synopsis

#include "petscpc.h" 
#include "petscksp.h" 
PetscErrorCode PCGAMGSetThresholdScale(PC pc, PetscReal v)

Logically Collective

Input Parameters

• pc - the preconditioner context

• v - the threshold value reduction, in [0,1]

Options Database Key

• -pc_gamg_threshold_scale v - set the relative threshold reduction on each level

Note

The initial threshold (for an arbitrary number of levels starting from the finest) can be set with PCGAMGSetThreshold(). This scaling is used for each subsequent coarsening, but must be called before PCGAMGSetThreshold(). Values above 1, which would make coarser levels filter more aggressively than the finest, are not allowed.

See Also

the Users Manual section on PCGAMG, the Users Manual section on PCMG, KSP: Linear System Solvers, PCGAMG, PCGAMGSetThreshold()

Level

advanced

Location

src/ksp/pc/impls/gamg/gamg.c

Implementations

PCGAMGSetThresholdScale_GAMG() in src/ksp/pc/impls/gamg/gamg.c

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