PCEisenstatSetNoDiagonalScaling

Causes the Eisenstat preconditioner, PCEISENSTAT 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

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

See Also

KSP: Linear System Solvers, PCEisenstatSetOmega(), PCEISENSTAT

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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