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

#include <Ifpack_IC.h>

Inheritance diagram for Ifpack_IC:

Collaboration diagram for Ifpack_IC:

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

virtual	~Ifpack_IC ()
	Ifpack_IC Destructor.

void	SetAbsoluteThreshold (double Athresh)
	Set absolute threshold value.

void	SetRelativeThreshold (double Rthresh)
	Set relative threshold value.

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

int	SetParameter (const std::string, const int)

int	SetParameter (const std::string, const double)

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

Epetra_RowMatrix &	Matrix ()

bool	IsInitialized () const
	Returns true if the preconditioner has been successfully initialized, false otherwise.

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...

int	ComputeSetup ()

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_IC 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.

double	GetAbsoluteThreshold ()
	Get absolute threshold value.

double	GetRelativeThreshold ()
	Get relative threshold value.

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

const Epetra_CrsMatrix &	U () const
	Returns the address of the U 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 the computation phase.

virtual double	ApplyInverseFlops () const
	Returns the number of flops in the application of the preconditioner.


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

The Ifpack_IC class computes a threshold (not level) based incomplete

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

Level of fill ratio. This defines the maximum number of entries per row/column in the factor, relative to the average number of nonzeros per row/col in A. The default value of 1.0 keeps the IC factor as sparse as A.
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 80 of file Ifpack_IC.h.

Constructor & Destructor Documentation

Ifpack_IC::Ifpack_IC ( Epetra_RowMatrix * A )

Ifpack_IC constuctor with variable number of indices per row.

Creates a Ifpack_IC object and allocates storage.

Parameters

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

Definition at line 61 of file Ifpack_IC.cpp.

References SetParameters().

Member Function Documentation

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

virtual

Returns the result of a Ifpack_IC 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 309 of file Ifpack_IC.cpp.

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

int Ifpack_IC::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 214 of file Ifpack_IC.cpp.

References Epetra_Time::ElapsedTime(), Initialize(), IsInitialized(), Epetra_Time::ResetStartTime(), and View.

double Ifpack_IC::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 370 of file Ifpack_IC.cpp.

References IsComputed().

int Ifpack_IC::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 126 of file Ifpack_IC.cpp.

Referenced by Compute().

int Ifpack_IC::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 230 of file Ifpack_IC.h.

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

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation