petsc-3.7.1 2016-05-15
PCEisenstatSetOmega
Sets the SSOR relaxation coefficient, omega, to use with Eisenstat's trick (where omega = 1.0 by default).
Synopsis
#include "petscpc.h"
PetscErrorCode PCEisenstatSetOmega(PC pc,PetscReal omega)
Logically Collective on PC Many br
Input Parameters
| pc | - the preconditioner context Many br |
| omega | - relaxation coefficient (0 < omega < 2) Many br |
Options Database Key
-pc_eisenstat_omega <omega> -Sets omega Many br
Notes
The Eisenstat trick implementation of SSOR requires about 50% of the Many brusual amount of floating point operations used for SSOR + Krylov method; Many brhowever, the preconditioned problem must be solved with both left Many brand right preconditioning. Many br
To use SSOR without the Eisenstat trick, employ the PCSOR preconditioner, Many brwhich can be chosen with the database options Many br
-pc_type sor -pc_sor_symmetric
Many br
Keywords
PC, Eisenstat, set, SOR, SSOR, relaxation, omega
See Also
PCSORSetOmega()
Level:intermediate
Location:src/ksp/pc/impls/eisens/eisen.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages