petsc-3.9.4 2018-09-11
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PCEisenstatSetNoDiagonalScaling

 Causes 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  PCEisenstatSetNoDiagonalScaling(PC pc,PetscBool flg)
Logically Collective on PC

Input Parameters

pc - the preconditioner context
flg - PETSC_TRUE turns off diagonal scaling inside the algorithm

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

PCEisenstatSetOmega()

Level

intermediate

Location

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

Implementations

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

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