petsc-3.9.4 2018-09-11
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PCEisenstatGetNoDiagonalScaling

 Tells if the Eisenstat preconditioner not to do additional diagonal preconditioning. For matrices with a constant along the diagonal, this may save a small amount of work.

Synopsis

#include "petscpc.h" 
PetscErrorCode  PCEisenstatGetNoDiagonalScaling(PC pc,PetscBool *flg)
Logically Collective on PC

Input Parameter

pc -the preconditioner context

Output Parameter

flg -PETSC_TRUE means there is no diagonal scaling applied

Options Database Key

-pc_eisenstat_no_diagonal_scaling -Activates PCEisenstatSetNoDiagonalScaling()

Note

If you use the KPSSetDiagonalScaling() or -ksp_diagonal_scale option then you will likley want to use this routine since it will save you some unneeded flops.

Keywords

PC, Eisenstat, use, diagonal, scaling, SSOR

See Also

PCEisenstatGetOmega()

Level

intermediate

Location

src/ksp/pc/impls/eisens/eisen.c

Implementations

PCEisenstatGetNoDiagonalScaling_Eisenstat in src/ksp/pc/impls/eisens/eisen.c

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