SNESKSPSetUseEW#

Sets SNES to the use Eisenstat-Walker method for computing relative tolerance for linear solvers within an inexact Newton method.

Synopsis#

#include "petscsnes.h"  
PetscErrorCode SNESKSPSetUseEW(SNES snes, PetscBool flag)

Logically Collective

Input Parameters#

Options Database Keys#

  • -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence

  • -snes_ksp_ew_version ver - version of Eisenstat-Walker method

  • -snes_ksp_ew_rtol0 - Sets rtol0

  • -snes_ksp_ew_rtolmax - Sets rtolmax

  • -snes_ksp_ew_gamma - Sets gamma

  • -snes_ksp_ew_alpha - Sets alpha

  • -snes_ksp_ew_alpha2 - Sets alpha2

  • -snes_ksp_ew_threshold - Sets threshold

Note#

The default is to use a constant relative tolerance for the inner linear solvers. Alternatively, one can use the Eisenstat-Walker method, where the relative convergence tolerance is reset at each Newton iteration according progress of the nonlinear solver.

Reference#

  • - * S. C. Eisenstat and H. F. Walker, “Choosing the forcing terms in an inexact Newton method”, SISC 17 (1), pp.16- 32, 1996.

See Also#

SNES: Nonlinear Solvers, KSP, SNES, SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()

Level#

advanced

Location#

src/snes/interface/snes.c

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