SNES_KSP_SetParametersEW

Sets parameters for Eisenstat-Walker convergence criteria for the linear solvers within an inexact Newton method.

Synopsis

#include "petscsnes.h"   
int SNES_KSP_SetParametersEW(SNES snes,int version,PetscReal rtol_0,
                             PetscReal rtol_max,PetscReal gamma2,PetscReal alpha,
                             PetscReal alpha2,PetscReal threshold)

Collective on SNES

Input Parameters

	snes	- SNES context
	version	- version 1 or 2 (default is 2)
	rtol_0	- initial relative tolerance (0 <= rtol_0 < 1)
	rtol_max	- maximum relative tolerance (0 <= rtol_max < 1)
	alpha	- power for version 2 rtol computation (1 < alpha <= 2)
	alpha2	- power for safeguard
	gamma2	- multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
	threshold	- threshold for imposing safeguard (0 < threshold < 1)

Note

Use PETSC_DEFAULT to retain the default for any of the parameters.

Reference

S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an inexact Newton method", Utah State University Math. Stat. Dept. Res. Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

Keywords