NOX::Solver::LineSearchBased Class Reference

Nonlinear solver based on a line search (i.e., damping). More...

#include <NOX_Solver_LineSearchBased.H>

Inheritance diagram for NOX::Solver::LineSearchBased:

[legend]Collaboration diagram for NOX::Solver::LineSearchBased:[legend]List of all members.


Public Member Functions
	LineSearchBased (NOX::Abstract::Group &grp, NOX::StatusTest::Generic &tests, NOX::Parameter::List &params)
	Constructor.
virtual	~LineSearchBased ()
	Destructor.
virtual bool	reset (NOX::Abstract::Group &grp, NOX::StatusTest::Generic &tests, NOX::Parameter::List &params)
	Reset the nonlinear solver for a new solve.
virtual bool	reset (NOX::Abstract::Group &grp, NOX::StatusTest::Generic &tests)
	A soft reset of the nonlinear solver for a new problem.
virtual NOX::StatusTest::StatusType	getStatus ()
	Check current convergence and failure status.
virtual NOX::StatusTest::StatusType	iterate ()
	Do one nonlinear method iteration and return status.
virtual NOX::StatusTest::StatusType	solve ()
	Solve the nonlinear problem and return final status.
virtual const NOX::Abstract::Group &	getSolutionGroup () const
	Return a reference to the current solution group.
virtual const NOX::Abstract::Group &	getPreviousSolutionGroup () const
	Return a reference to the previous solution group.
virtual int	getNumIterations () const
	Get number of iterations.
virtual const NOX::Parameter::List &	getParameterList () const
	Return a refernece to the solver parameters.
virtual double	getStepSize () const
	Return the line search step size from the current iteration.
Protected Member Functions
virtual void	init ()
	Print out initialization information and calcuation the RHS.
virtual void	printUpdate ()
	Prints the current iteration information.
Protected Attributes
NOX::Abstract::Group *	solnPtr
	Current solution.
NOX::Abstract::Group *	oldSolnPtr
	Previous solution pointer.
NOX::Abstract::Group &	oldSoln
	Previous solution reference.
NOX::Abstract::Vector *	dirPtr
	Current search direction.pointer.
NOX::Abstract::Vector &	dir
	Current search direction.reference.
NOX::StatusTest::Generic *	testPtr
	Stopping test.
NOX::Parameter::List *	paramsPtr
	Input parameters.
NOX::Utils	utils
	Utils.
NOX::LineSearch::Manager	lineSearch
	Linesearch.
NOX::Direction::Manager	direction
	Search Direction.
double	step
	Current step.
int	nIter
	Number of nonlinear iterations.
NOX::StatusTest::StatusType	status
	Status of nonlinear solver.
NOX::Parameter::PrePostOperator *	prePostOperatorPtr
	Pointer to a user defined NOX::Abstract::PrePostOperator object.
bool	havePrePostOperator
	True if a PrePostOperator was registered with the solver.

Detailed Description

Nonlinear solver based on a line search (i.e., damping).

Solves $F(x)=0$ using an iterative line-search-based method.

Each iteration, the solver does the following.

Compute a search direction via a NOX::Direction method
Compute a step length $\lambda$ and update as $x_{\rm new} = x_{\rm old} + \lambda d$ via a NOX::LineSearch method.

The iterations progress until the status tests (see NOX::StatusTest) determine either failure or convergence.

Note:: To support several line searches and status tests, this version of the solver has a getStepSize() function that returns $\lambda$ .

Input Parameters

The following parameter list entries are valid for this solver:

"Line Search" - Sublist of the line search parameters, passed to the NOX::LineSearch::Manager constructor. Defaults to an empty list.

"Direction" - Sublist of the direction parameters, passed to the NOX::Direction::Manager constructor. Defaults to an empty list.

"Solver Options" - Sublist of general solver options.
- "User Defined Pre/Post Operator" is supported. See NOX::Parameter::PrePostOperator for more details.

Output Parameters

Every time solve() is called, a sublist for output parameters called "Output" will be created and contain the following parameters.

"Output":

"Nonlinear Iterations" - Number of nonlinear iterations

"2-Norm of Residual" - Two-norm of final residual

Author:: Tammy Kolda (SNL 8950), Roger Pawlowski (SNL 9233)

Constructor & Destructor Documentation

NOX::Solver::LineSearchBased::LineSearchBased ( NOX::Abstract::Group & grp,

NOX::StatusTest::Generic & tests,

NOX::Parameter::List & params

)

Constructor.
See reset(NOX::Abstract::Group&, NOX::StatusTest::Generic&, NOX::Parameter::List&) for description

Member Function Documentation

bool NOX::Solver::LineSearchBased::reset ( NOX::Abstract::Group & grp,

NOX::StatusTest::Generic & tests

) [virtual]

A soft reset of the nonlinear solver for a new problem.
This is a light-weight version of reset that takes no parameter list. Therefore, this reset only resets counters, the initial guess (contained in the grp argument) and new status tests (contained in the tests argument).
This reset allows problems to bypass the potentially time consuming parsing of the parameter lists.
Implements NOX::Solver::Generic.

bool NOX::Solver::LineSearchBased::reset ( NOX::Abstract::Group & grp,

NOX::StatusTest::Generic & tests,

NOX::Parameter::List & params

) [virtual]

Reset the nonlinear solver for a new solve.

Parameters:

grp On input, contains the intial guess. On output, contains the solution.

tests Status tests to check for convergence or failure. These tests will be modified by the solver.

params List of parameters. These parameters will be modified by the solver.

Note:
All the objects passed to reset() will be modified.
The group object will be cloned via NOX::Abstract::Group::clone(), and the vectors within will also be individually cloned via NOX::Abstract::Vector::clone().

Warning:
If the contents of grp, tests, or params are modified by the calling program after calling reset(), then the behavior of iterate() and solve() are completely undefined. To remedy this, call reset() again with the modified objects.

Implements NOX::Solver::Generic.

NOX::StatusTest::StatusType NOX::Solver::LineSearchBased::solve ( ) [virtual]

Solve the nonlinear problem and return final status.
By "solve", we call iterate() until the NOX::StatusTest value is either NOX::StatusTest::Converged or NOX::StatusTest::Failed.
Implements NOX::Solver::Generic.

Member Data Documentation

NOX::Abstract::Vector* NOX::Solver::LineSearchBased::dirPtr [protected]

Current search direction.pointer.
We have both a pointer and a reference because we need to create a DERIVED object and then want to have a reference to it.

NOX::Abstract::Group* NOX::Solver::LineSearchBased::oldSolnPtr [protected]

Previous solution pointer.
We have both a pointer and a reference because we need to create a DERIVED object and then want to have a reference to it.

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

NOX_Solver_LineSearchBased.H
NOX_Solver_LineSearchBased.C

Generated on Thu Sep 18 12:43:34 2008 for NOX by

1.3.9.1

NOX::Solver::LineSearchBased Class Reference

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation