Ifpack_ICT: A class for constructing and using an incomplete Cholesky factorization of a given Epetra_RowMatrix. More...

#include <Ifpack_ICT.h>

Inheritance diagram for Ifpack_ICT:

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Collaboration diagram for Ifpack_ICT:

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Public Member Functions
	Ifpack_ICT (const Epetra_RowMatrix *A)
	Ifpack_ICT constuctor with variable number of indices per row. More...

virtual	~Ifpack_ICT ()
	Ifpack_ICT Destructor.

int	SetParameters (Teuchos::ParameterList &parameterlis)
	Set parameters using a Teuchos::ParameterList object.

const Epetra_RowMatrix &	Matrix () const
	Returns a reference to the matrix to be preconditioned.

bool	IsInitialized () const
	Returns `true` is the preconditioner has been successfully initialized.

int	Initialize ()
	Initialize L and U with values from user matrix A. More...

int	Compute ()
	Compute IC factor U using the specified graph, diagonal perturbation thresholds and relaxation parameters. More...

bool	IsComputed () const
	If factor is completed, this query returns true, otherwise it returns false.

int	ApplyInverse (const Epetra_MultiVector &X, Epetra_MultiVector &Y) const
	Returns the result of a Ifpack_ICT forward/back solve on a Epetra_MultiVector X in Y. More...

int	Apply (const Epetra_MultiVector &X, Epetra_MultiVector &Y) const

double	Condest (const Ifpack_CondestType CT=Ifpack_Cheap, const int MaxIters=1550, const double Tol=1e-9, Epetra_RowMatrix *Matrix_in=0)
	Returns the maximum over all the condition number estimate for each local ILU set of factors. More...

double	Condest () const
	Returns the computed condition number estimate, or -1.0 if not computed.

int	NumGlobalNonzeros () const
	Returns the number of nonzero entries in the global graph.

long long	NumGlobalNonzeros64 () const

int	NumMyNonzeros () const
	Returns the number of nonzero entries in the local graph.

const Epetra_CrsMatrix &	H () const
	Returns the address of the D factor associated with this factored matrix.

const char *	Label () const

int	SetLabel (const char *Label_in)

virtual std::ostream &	Print (std::ostream &os) const
	Prints basic information on iostream. This function is used by operator<<.

virtual int	NumInitialize () const
	Returns the number of calls to Initialize().

virtual int	NumCompute () const
	Returns the number of calls to Compute().

virtual int	NumApplyInverse () const
	Returns the number of calls to ApplyInverse().

virtual double	InitializeTime () const
	Returns the time spent in Initialize().

virtual double	ComputeTime () const
	Returns the time spent in Compute().

virtual double	ApplyInverseTime () const
	Returns the time spent in ApplyInverse().

virtual double	InitializeFlops () const
	Returns the number of flops in the initialization phase.

virtual double	ComputeFlops () const
	Returns the number of flops in all applications of Compute().

virtual double	ApplyInverseFlops () const
	Returns the number of flops in all applications of ApplyInverse().

double	LevelOfFill () const
	Returns the level-of-fill. More...

double	AbsoluteThreshold () const
	Returns the absolute threshold.

double	RelativeThreshold () const
	Returns the relative threshold.

double	RelaxValue () const
	Returns the relaxation value.

double	DropTolerance () const
	Returns the drop threshold.


int	SetUseTranspose (bool UseTranspose_in)
	If set true, transpose of this operator will be applied. More...

double	NormInf () const
	Returns 0.0 because this class cannot compute Inf-norm.

bool	HasNormInf () const
	Returns false because this class cannot compute an Inf-norm.

bool	UseTranspose () const
	Returns the current UseTranspose setting.

const Epetra_Map &	OperatorDomainMap () const
	Returns the Epetra_Map object associated with the domain of this operator.

const Epetra_Map &	OperatorRangeMap () const
	Returns the Epetra_Map object associated with the range of this operator.

const Epetra_Comm &	Comm () const
	Returns the Epetra_BlockMap object associated with the range of this matrix operator.

Detailed Description

Ifpack_ICT: A class for constructing and using an incomplete Cholesky factorization of a given Epetra_RowMatrix.

The Ifpack_ICT class computes a threshold based incomplete

LDL^T factorization of a given Epetra_RowMatrix. The factorization that is produced is a function of several parameters:

Maximum number of entries per row/column in factor - The factorization will contain at most this number of nonzero terms in each row/column of the factorization.
Diagonal perturbation - Prior to computing the factorization, it is possible to modify the diagonal entries of the matrix for which the factorization will be computing. If the absolute and relative perturbation values are zero and one, respectively, the factorization will be compute for the original user matrix A. Otherwise, the factorization will computed for a matrix that differs from the original user matrix in the diagonal values only. Details can be found in ifp_diag_pert.

Definition at line 89 of file Ifpack_ICT.h.

Constructor & Destructor Documentation

Ifpack_ICT::Ifpack_ICT ( const Epetra_RowMatrix * A )

Ifpack_ICT constuctor with variable number of indices per row.

Creates a Ifpack_ICT object and allocates storage.

Parameters

In	A - User matrix to be factored.
In	Graph - Graph generated by Ifpack_IlukGraph.

Definition at line 63 of file Ifpack_ICT.cpp.

Member Function Documentation

int Ifpack_ICT::ApplyInverse	(	const Epetra_MultiVector &	X,
		Epetra_MultiVector &	Y
	)		const

virtual

Returns the result of a Ifpack_ICT forward/back solve on a Epetra_MultiVector X in Y.

Parameters

In	Trans -If true, solve transpose problem.
In	X - A Epetra_MultiVector of dimension NumVectors to solve for.
Out	Y -A Epetra_MultiVector of dimension NumVectorscontaining result.

Returns: Integer error code, set to 0 if successful.

Implements Ifpack_Preconditioner.

Definition at line 455 of file Ifpack_ICT.cpp.

References Epetra_Time::ElapsedTime(), IsComputed(), and Epetra_Time::ResetStartTime().

int Ifpack_ICT::Compute ( )

virtual

Compute IC factor U using the specified graph, diagonal perturbation thresholds and relaxation parameters.

This function computes the RILU(k) factors L and U using the current:

Ifpack_IlukGraph specifying the structure of L and U.
Value for the RILU(k) relaxation parameter.
Value for the a priori diagonal threshold values.

InitValues() must be called before the factorization can proceed.

Implements Ifpack_Preconditioner.

Definition at line 438 of file Ifpack_ICT.cpp.

References Epetra_BlockMap::GlobalIndicesInt(), Epetra_BlockMap::GlobalIndicesLongLong(), and Epetra_RowMatrix::RowMatrixRowMap().

double Ifpack_ICT::Condest	(	const Ifpack_CondestType	CT = `Ifpack_Cheap`,
		const int	MaxIters = `1550`,
		const double	Tol = `1e-9`,
		Epetra_RowMatrix *	Matrix_in = `0`
	)

virtual

Returns the maximum over all the condition number estimate for each local ILU set of factors.

This functions computes a local condition number estimate on each processor and return the maximum over all processor of the estimate.

Parameters

In	Trans -If true, solve transpose problem.
Out	ConditionNumberEstimate - The maximum across all processors of the infinity-norm estimate of the condition number of the inverse of LDU.

Implements Ifpack_Preconditioner.

Definition at line 502 of file Ifpack_ICT.cpp.

References IsComputed().

int Ifpack_ICT::Initialize ( )

virtual

Initialize L and U with values from user matrix A.

Copies values from the user's matrix into the nonzero pattern of L and U.

Parameters

In	A - User matrix to be factored.

Warning: The graph of A must be identical to the graph passed in to Ifpack_IlukGraph constructor.

Implements Ifpack_Preconditioner.

Definition at line 138 of file Ifpack_ICT.cpp.

References Comm(), Epetra_Time::ElapsedTime(), Matrix(), Epetra_RowMatrix::NumMyRows(), and Epetra_Time::ResetStartTime().

double Ifpack_ICT::LevelOfFill ( ) const

inline

Returns the level-of-fill.

Note: : if 1.0, then the factored matrix contains approximatively the same number of elements of A.

Definition at line 305 of file Ifpack_ICT.h.

Referenced by Print(), and SetParameters().

int Ifpack_ICT::SetUseTranspose ( bool UseTranspose_in )

inlinevirtual

If set true, transpose of this operator will be applied.

This flag allows the transpose of the given operator to be used implicitly.  Setting this flag
affects only the Apply() and ApplyInverse() methods.  If the implementation of this interface
does not support transpose use, this method should return a value of -1.

Parameters

In	UseTranspose_in -If true, multiply by the transpose of operator, otherwise just use operator.

Returns: Always returns 0.

Implements Epetra_Operator.

Definition at line 212 of file Ifpack_ICT.h.

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

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation