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" 
PetscErrorCode PCSORSetSymmetric(PC pc, MatSORType flag)

Logically Collective

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

Note

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

• -pc_type eisenstat - Activates Eisenstat trick

See Also

KSP: Linear System Solvers, PCSOR, PCEisenstatSetOmega(), PCSORSetIterations(), PCSORSetOmega()

Level

intermediate

Location

src/ksp/pc/impls/sor/sor.c

Implementations

PCSORSetSymmetric_SOR() in src/ksp/pc/impls/sor/sor.c

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