PCEisenstatSetOmega

Sets the SSOR relaxation coefficient, omega, to use with Eisenstat's trick (where omega = 1.0 by default).

Synopsis

int PCEisenstatSetOmega(PC pc,double omega)

Input Parameters

pc - the preconditioner context
omega - relaxation coefficient (0 < omega < 2)

Collective on PC

Options Database Key

-pc_eisenstat_omega <omega> -Sets omega

Notes

The Eisenstat trick implementation of SSOR requires about 50% of theusual amount of floating point operations used for SSOR + Krylov method; however, the preconditioned problem must be solved with both leftand right preconditioning.

To use SSOR without the Eisenstat trick, employ the PCSOR preconditioner, which can be chosen with the database options

   -pc_type  sor  -pc_sor_symmetric

Keywords

PC, Eisenstat, set, SOR, SSOR, relaxation, omega

See Also

PCSORSetOmega()

Location: src/pc/impls/eisen/eisen.c
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