SNESLineSearchCubic

Performs a cubic line search (default line search method).

Synopsis

PetscErrorCode PETSCSNES_DLLEXPORT SNESLineSearchCubic(SNES snes,void *lsctx,Vec x,Vec f,Vec g,Vec y,Vec w,PetscReal fnorm,PetscReal *ynorm,PetscReal *gnorm,PetscTruth *flag)

Collective on SNES

Input Parameters

	snes	- nonlinear context
	lsctx	- optional context for line search (not used here)
	x	- current iterate
	f	- residual evaluated at x
	y	- search direction
	w	- work vector
	fnorm	- 2-norm of f

Output Parameters

	g	- residual evaluated at new iterate y
	w	- new iterate
	gnorm	- 2-norm of g
	ynorm	- 2-norm of search length
	flag	- PETSC_TRUE if line search succeeds; PETSC_FALSE on failure.

Options Database Key

 -snes_ls cubic - Activates SNESLineSearchCubic()

Notes

This line search is taken from "Numerical Methods for Unconstrained Optimization and Nonlinear Equations" by Dennis and Schnabel, page 325.

Keywords

SNES, nonlinear, line search, cubic