petsc-3.7.7 2017-09-25

PCSORGetSymmetric

Gets the form the SOR preconditioner is using; backward, or forward relaxation. The local variants perform SOR on each processor. By default forward relaxation is used.

Synopsis

#include "petscpc.h" 
PetscErrorCode  PCSORGetSymmetric(PC pc,MatSORType *flag)

Logically Collective on PC

Input Parameter

pc -the preconditioner context

Output Parameter

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