petsc-3.14.6 2021-03-30

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

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

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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