petsc-3.6.1 2015-08-06

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