Ifpack2::Factory Class Reference

A factory class to create Ifpack2 preconditioners. More...

#include <Ifpack2_Factory.hpp>

List of all members.

Static Public Member Functions
template<class MatrixType >
static Teuchos::RCP < Ifpack2::Preconditioner < typename MatrixType::scalar_type, typename MatrixType::local_ordinal_type, typename MatrixType::global_ordinal_type, typename MatrixType::node_type > >	create (const std::string &prec_type, const Teuchos::RCP< const MatrixType > &matrix, const int overlap=0)
	Creates an instance of Ifpack2_Preconditioner given the string name of the preconditioner type (throws exception if given unrecognized name).

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Detailed Description

A factory class to create Ifpack2 preconditioners.

Ifpack2::Factory contains just one method: create(). Using Ifpack2::Factory::create(), users can easily create a variety of Ifpack2 preconditioners.

create requires 3 arguments:

• a string, indicating the preconditioner to be built;
• a pointer to a Tpetra::RowMatrix, representing the matrix to be used to define the preconditioner;
• an optional integer (defaulted to 0), that specifies the amount of overlap among the processes.

The first argument can assume the following values:

• "DIAGONAL" : returns an instance of Ifpack2::Diagonal.
• "RELAXATION" : returns an instance of Ifpack2::Relaxation.
• "CHEBYSHEV" : returns an instance of Ifpack2::Chebyshev (overlap is ignored).
• "ILUT" : returns an instance of Ifpack2::ILUT.
• "RILUK" : returns an instance of Ifpack2::RILUK.
• otherwise, create() returns Teuchos::null.

The following fragment of code shows the basic usage of this class.

#include "Ifpack2_Factory.hpp"

...
typedef double Scalar;
typedef int    LocalOrdinal;
typedef int    GlobalOrdinal;
typedef Tpetra::DefaultPlatform::DefaultPlatformType::NodeType Node;
typedef Tpetra::CrsMatrix<Scalar,LocalOrdinal,GlobalOrdinal,Node> TCrsMatrix;
typedef Ifpack2::Preconditioner<Scalar,LocalOrdinal,GlobalOrdinal,Node> TPrecond;
...
Ifpack2::Factory factory;

Teuchos::RCP<TCrsMatrix> A; // A is fillComplete()'d.
std::string PrecType = "ILUT"; // use incomplete LU on each process
Teuchos::RCP<TPrecond> prec = factory.create(PrecType, A);

Teuchos::ParameterList params;
params.set("fact: ilut level-of-fill", 5.0); // use ILUT(fill=5, drop=0)

prec->setParameters(List);
prec->initialize();
prec->compute();

// now prec can be used as a preconditioner

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Member Function Documentation

template<class MatrixType >

Teuchos::RCP< Ifpack2::Preconditioner< typename MatrixType::scalar_type, typename MatrixType::local_ordinal_type, typename MatrixType::global_ordinal_type, typename MatrixType::node_type > > Ifpack2::Factory::create	(	const std::string &	prec_type,
		const Teuchos::RCP< const MatrixType > &	matrix,
		const int	overlap = 0
	)		[static]

Creates an instance of Ifpack2_Preconditioner given the string name of the preconditioner type (throws exception if given unrecognized name).

Parameters:

PrecType	(In) - String name of preconditioner type to be created.
Matrix	(In) - Matrix used to define the preconditioner
overlap	(In) - specified overlap, defaulted to 0.

Returns 0 if the preconditioner with that input name does not exist. Otherwise, return a newly created preconditioner object. Note that the client is responsible for calling delete on the returned object once it is finished using it!

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

• Ifpack2_Factory.hpp