petsc-3.3-p7 2013-05-11

SNESKSPSetParametersEW

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

Synopsis

#include "petscsnes.h"  
#include "petscdmshell.h" 
#include "petscsys.h" 
PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,
                                                      PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)

Logically Collective on SNES

Input Parameters

	snes	- SNES context
	version	- version 1, 2 (default is 2) or 3
	rtol_0	- initial relative tolerance (0 <= rtol_0 < 1)
	rtol_max	- maximum relative tolerance (0 <= rtol_max < 1)
	gamma	- multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
	alpha	- power for version 2 rtol computation (1 < alpha <= 2)
	alpha2	- power for safeguard
	threshold	- threshold for imposing safeguard (0 < threshold < 1)

Note

Version 3 was contributed by Luis Chacon, June 2006.

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