A line search that determines the step size by capping the magnitue of specific entries of the direction vector. The limits are specified by a user defined vector. More...

#include <NOX_LineSearch_SafeguardedStep.H>

Inheritance diagram for NOX::LineSearch::SafeguardedStep:

[legend]

Collaboration diagram for NOX::LineSearch::SafeguardedStep:

[legend]

Public Member Functions
	SafeguardedStep (const Teuchos::RCP< NOX::GlobalData > &gd, Teuchos::ParameterList &params)
	Constructor.

bool	reset (const Teuchos::RCP< NOX::GlobalData > &gd, Teuchos::ParameterList &params)

bool	compute (NOX::Abstract::Group &newgrp, double &step, const NOX::Abstract::Vector &dir, const NOX::Solver::Generic &s)
	Perform a line search. More...

Teuchos::RCP< const Teuchos::ParameterList >	getValidParameters ()

Public Member Functions inherited from NOX::LineSearch::Generic
	Generic ()
	Default constructor.

virtual	~Generic ()
	Destructor.

Detailed Description

A line search that determines the step size by capping the magnitue of specific entries of the direction vector. The limits are specified by a user defined vector.

Member Function Documentation

bool NOX::LineSearch::SafeguardedStep::compute	(	NOX::Abstract::Group &	grp,
		double &	step,
		const NOX::Abstract::Vector &	dir,
		const NOX::Solver::Generic &	s
	)

virtual

Perform a line search.

On input:

Parameters

grp	The initial solution vector, $x_{\rm old}$ .
dir	A vector of directions to be used in the line search, .
s	The nonlinear solver.

On output:

Parameters

step	The distance the direction was scaled, $\lambda$ .
grp	The `grp` is updated with a new solution, $x_{\rm new}$ , resulting from the linesearch. Normally, for a single direction line search, this is computed as:

$x_{\rm new} = x_{\rm old} + \lambda d.$

Ideally, $\|F(x_{\rm new})\| < \|F(x_{\rm old})\|$ (e.g the final direction is a descent direction).

Note that the dir object is a std::vector. For typical line searches as described in the above equation, this vector is of size one. We have used a std::vector to allow for special cases of multi-directional line searches such as the Bader/Schnabel curvillinear line search.

Return value is true for a successful line search computation.

Implements NOX::LineSearch::Generic.

References NOX::Abstract::Group::computeX(), NOX::Utils::Details, NOX::Abstract::Group::getX(), NOX::Utils::InnerIteration, NOX::Abstract::Vector::MaxNorm, NOX::Abstract::Vector::norm(), NOX::Abstract::Vector::print(), and NOX::Abstract::Vector::scale().

The documentation for this class was generated from the following files:

NOX_LineSearch_SafeguardedStep.H
NOX_LineSearch_SafeguardedStep.C

Public Member Functions

Detailed Description

Member Function Documentation