petsc-3.10.5 2019-03-28
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 <fill> -Sets fill amount
Note
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 parameter has NOTHING to do with the levels-of-fill of ILU(). That is set with PCFactorSetLevels() or -pc_factor_levels.
Keywords
PC, set, factorization, direct, fill
Level
intermediate
Location
src/ksp/pc/impls/factor/factor.c
Implementations
PCFactorSetFill_Factor in src/ksp/pc/impls/factor/factimpl.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages