Various convergence tests based on the norm of the change in the solution vector, , between outer iterations. More...

#include <NOX_StatusTest_NormUpdate.H>

Inheritance diagram for NOX::StatusTest::NormUpdate:

Collaboration diagram for NOX::StatusTest::NormUpdate:

Public Types
enum	ScaleType { Unscaled , Scaled }
	Type that determines whether to scale the norm by the problem size. More...

Public Member Functions
	NormUpdate (double tolerance, NOX::Abstract::Vector::NormType ntype, ScaleType stype=Scaled)
	Constructor for absolute norm.
	NormUpdate (double tolerance, ScaleType stype=Scaled)
	Constructor for absolute norm.
virtual	~NormUpdate ()
	Destructor.
virtual NOX::StatusTest::StatusType	checkStatus (const NOX::Solver::Generic &problem, NOX::StatusTest::CheckType checkType)
	Test the stopping criterion
virtual NOX::StatusTest::StatusType	getStatus () const
	Return the result of the most recent checkStatus call.
virtual std::ostream &	print (std::ostream &stream, int indent=0) const
	Output formatted description of stopping test to output stream.
virtual double	getNormUpdate () const
	Returns the value of the Update-norm computed in the last call to checkStatus.
virtual double	getTolerance () const
	Returns the true tolerance.
Public Member Functions inherited from NOX::StatusTest::Generic
	Generic ()
	Constructor.
virtual	~Generic ()
	Destructor.

Detailed Description

Various convergence tests based on the norm of the change in the solution vector, , between outer iterations.

If checkStatusEfficiently is called with the type set to NOX::StatusTest::None, then the status is set to NOX::StatusTest::Unevaluated and returned. (Also #normUpdate is set to -1.0.)

If checkStatusEfficiently is called on the first iteration, then the status is set to NOX::StatusTest::Unconverged and returned. (Also #normUpdate is set to -1.0.)

If checkStatusEfficiently is called on a problem where the solution group does not have F evaluated (i.e., problem.getSolutionGroup().isF() is false), then the status is set to NOX::StatusTest::Unconverged and returned. (Also #normUpdate is set to -1.0.)

Finally, we return NOX::StatusTest::Converged if $\alpha < \beta$ and NOX::StatusTest::Uncoverged otherwise. Here $\alpha$ represents the norm of $\Delta x$ and $\beta$ represents the tolerance. We define:

$\‍[ \Delta x = x_k - x_{k-1} \‍]$

where is the solution vector of the -th nonlinear iterate.

Let $\gamma$ denote an optional scale factor defined as

$\gamma = \frac{1}{n}$ if sType in the constructor is NOX::NormF::Scaled, and
$\gamma = 1$ if sType in the constructor is NOX::NormF::Unscaled.

Then $\alpha$ is defined as follows:

If nType in the constructor is Abstract::Vector::TWO, then
$\‍[ \alpha = \sqrt{ \gamma \sum_{i=1}^n \Delta x_i^2 } \‍]$
If nType in the constructor is Abstract::Vector::ONE, then
$\‍[ \alpha = \gamma \sum_{i=1}^n | \Delta x_i | \‍]$
If nType in the constructor is Abstract::Vector::INF, then
$\‍[ \alpha = \gamma \max_{i} | \Delta x_i | \‍]$

Finally, $\beta$ is set to the tolerance in the constructor, i.e.,

$\‍[ \beta = \mbox{tolerance} \‍]$

Member Enumeration Documentation

◆ ScaleType

enum NOX::StatusTest::NormUpdate::ScaleType

Type that determines whether to scale the norm by the problem size.

Enumerator
Unscaled	No norm scaling.
Scaled	Scale the norm by the length of the vector.

Constructor & Destructor Documentation

◆ NormUpdate() [1/2]

NormUpdate::NormUpdate	(	double	tolerance,
		NOX::Abstract::Vector::NormType	ntype,
		ScaleType	stype = Scaled )

Constructor for absolute norm.

This constructor defaults to the Absolute tolerance type.

References NOX::StatusTest::Unevaluated.

◆ NormUpdate() [2/2]

NormUpdate::NormUpdate	(	double	tolerance,
		ScaleType	stype = Scaled )

Constructor for absolute norm.

This constructor defaults to the Absolute ToleranceType and TWO NormType.

References NOX::StatusTest::Unevaluated.

Member Function Documentation

◆ checkStatus()

StatusType NormUpdate::checkStatus	(	const NOX::Solver::Generic &	problem,
		NOX::StatusTest::CheckType	checkType )

virtual

Test the stopping criterion

The test can (and should, if possible) be skipped if checkType is NOX::StatusType::None. If the test is skipped, then the status should be set to NOX::StatusTest::Unevaluated.

Implements NOX::StatusTest::Generic.

References NOX::Abstract::Vector::clone(), NOX::StatusTest::Converged, NOX::Solver::Generic::getNumIterations(), NOX::Solver::Generic::getPreviousSolutionGroup(), NOX::Solver::Generic::getSolutionGroup(), NOX::Abstract::Group::getX(), NOX::Abstract::Group::isF(), NOX::Abstract::Vector::length(), NOX::StatusTest::None, Scaled, NOX::Abstract::Vector::TwoNorm, NOX::StatusTest::Unconverged, and NOX::StatusTest::Unevaluated.