PCFactorSetFill#

Indicate the amount of fill you expect in the factored matrix, fill = number nonzeros in factor/number nonzeros in original matrix.

Synopsis#

#include "petscpc.h" 
PetscErrorCode PCFactorSetFill(PC pc, PetscReal fill)

Not Collective, each process can expect a different amount of fill

Input Parameters#

  • pc - the preconditioner context

  • fill - amount of expected fill

Options Database Key#

  • -pc_factor_fill - Sets fill amount

Notes#

For sparse matrix factorizations it is difficult to predict how much fill to expect. By running with the option -info PETSc will print the actual amount of fill used; allowing you to set the value accurately for future runs. Default PETSc uses a value of 5.0

This is ignored for most solver packages

This parameter has NOTHING to do with the levels-of-fill of ILU(). That is set with PCFactorSetLevels() or -pc_factor_levels.

See Also#

PCLU, PCCHOLESKY, PCILU, PCICC, PCFactorSetReuseFill()

Level#

intermediate

Location#

src/ksp/pc/impls/factor/factor.c

Implementations#

PCFactorSetFill_Factor in src/ksp/pc/impls/factor/factimpl.c


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