PCSORSetSymmetric

 Sets the SOR preconditioner to use symmetric (SSOR), backward, or forward relaxation. The local variants perform SOR on each processor. By default forward relaxation is used.

Synopsis

#include "petscpc.h" 
int PCSORSetSymmetric(PC pc,MatSORType flag)
Collective on PC

Input Parameters

pc - the preconditioner context
flag - one of the following 
    SOR_FORWARD_SWEEP
    SOR_BACKWARD_SWEEP
    SOR_SYMMETRIC_SWEEP
    SOR_LOCAL_FORWARD_SWEEP
    SOR_LOCAL_BACKWARD_SWEEP
    SOR_LOCAL_SYMMETRIC_SWEEP

Options Database Keys

-pc_sor_symmetric - Activates symmetric version
-pc_sor_backward - Activates backward version
-pc_sor_local_forward - Activates local forward version
-pc_sor_local_symmetric - Activates local symmetric version
-pc_sor_local_backward - Activates local backward version

Notes

To use the Eisenstat trick with SSOR, employ the PCEISENSTAT preconditioner, which can be chosen with the option
-pc_type eisenstat -Activates Eisenstat trick

Keywords

PC, SOR, SSOR, set, relaxation, sweep, forward, backward, symmetric

See Also

PCEisenstatSetOmega(), PCSORSetIterations(), PCSORSetOmega()

Level:intermediate
Location:src/sles/pc/impls/sor/sor.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages

Examples

src/sles/examples/tutorials/ex21f.F.html