SNESSetFromOptions

Sets various SNES and SLES parameters from user options.

#include "petscsnes.h"  
int SNESSetFromOptions(SNES snes)

Collective on SNES

snes -the SNES context

	-snes_type <type>	- ls, tr, umls, umtr, test
	-snes_stol	- convergence tolerance in terms of the norm of the change in the solution between steps
	-snes_atol <atol>	- absolute tolerance of residual norm
	-snes_rtol <rtol>	- relative decrease in tolerance norm from initial
	-snes_max_it <max_it>	- maximum number of iterations
	-snes_max_funcs <max_funcs>	- maximum number of function evaluations
	-snes_max_fail <max_fail>	- maximum number of failures
	-snes_trtol <trtol>	- trust region tolerance
	-snes_no_convergence_test	- skip convergence test in nonlinear or minimization solver; hence iterations will continue until max_it or some other criterion is reached. Saves expense of convergence test
	-snes_monitor	- prints residual norm at each iteration
	-snes_vecmonitor	- plots solution at each iteration
	-snes_vecmonitor_update	- plots update to solution at each iteration
	-snes_xmonitor	- plots residual norm at each iteration
	-snes_fd	- use finite differences to compute Jacobian; very slow, only for testing
	-snes_mf_ksp_monitor	- if using matrix-free multiply then print h at each KSP iteration

	-snes_ksp_ew_conv	- use Eisenstat-Walker method for determining linear system convergence
	-snes_ksp_ew_version ver	- version of Eisenstat-Walker method
	-snes_ksp_ew_rtol0 <rtol0>	- Sets rtol0
	-snes_ksp_ew_rtolmax <rtolmax>	- Sets rtolmax
	-snes_ksp_ew_gamma <gamma>	- Sets gamma
	-snes_ksp_ew_alpha <alpha>	- Sets alpha
	-snes_ksp_ew_alpha2 <alpha2>	- Sets alpha2
	-snes_ksp_ew_threshold <threshold>	- Sets threshold

To see all options, run your program with the -help option or consult the users manual.

SNES, nonlinear, set, options, database