Ifpack2 Templated Preconditioning Package Version 1.0
Ifpack2::ILUT< MatrixType > Class Template Reference

ILUT (incomplete LU factorization with threshold) of a Tpetra sparse matrix. More...

#include <Ifpack2_ILUT_decl.hpp>

Inheritance diagram for Ifpack2::ILUT< MatrixType >:
Inheritance graph
[legend]

List of all members.

Public Member Functions

Constructors and Destructors
 ILUT (const Teuchos::RCP< const Tpetra::RowMatrix< scalar_type, local_ordinal_type, global_ordinal_type, node_type > > &A)
 Constructor.
virtual ~ILUT ()
 Destructor.
Methods for setting up and computing the incomplete factorization
void setParameters (const Teuchos::ParameterList &params)
 Set preconditioner parameters.
void initialize ()
 Clear any previously computed factors.
bool isInitialized () const
 Returns true if the preconditioner has been successfully initialized.
void compute ()
 Compute factors L and U using the specified diagonal perturbation thresholds and relaxation parameters.
bool isComputed () const
 If compute() is completed, this query returns true, otherwise it returns false.
Methods implementing Tpetra::Operator.
void apply (const Tpetra::MultiVector< scalar_type, local_ordinal_type, global_ordinal_type, node_type > &X, Tpetra::MultiVector< scalar_type, local_ordinal_type, global_ordinal_type, node_type > &Y, Teuchos::ETransp mode=Teuchos::NO_TRANS, scalar_type alpha=Teuchos::ScalarTraits< scalar_type >::one(), scalar_type beta=Teuchos::ScalarTraits< scalar_type >::zero()) const
 Returns the result of a ILUT forward/back solve on a Tpetra::MultiVector X in Y.
Teuchos::RCP< const
Tpetra::Map
< local_ordinal_type,
global_ordinal_type, node_type > > 
getDomainMap () const
 Tpetra::Map representing the domain of this operator.
Teuchos::RCP< const
Tpetra::Map
< local_ordinal_type,
global_ordinal_type, node_type > > 
getRangeMap () const
 Tpetra::Map representing the range of this operator.
bool hasTransposeApply () const
 Whether this object's apply() method can apply the transpose (or conjugate transpose, if applicable).
Mathematical functions.
template<class DomainScalar , class RangeScalar >
void applyTempl (const Tpetra::MultiVector< DomainScalar, local_ordinal_type, global_ordinal_type, node_type > &X, Tpetra::MultiVector< RangeScalar, local_ordinal_type, global_ordinal_type, node_type > &Y, Teuchos::ETransp mode=Teuchos::NO_TRANS, RangeScalar alpha=Teuchos::ScalarTraits< scalar_type >::one(), RangeScalar beta=Teuchos::ScalarTraits< scalar_type >::zero()) const
 Returns the result of a ILUT forward/back solve on a Tpetra::MultiVector X in Y.
magnitude_type computeCondEst (CondestType CT=Cheap, local_ordinal_type MaxIters=1550, magnitude_type Tol=1e-9, const Teuchos::Ptr< const Tpetra::RowMatrix< scalar_type, local_ordinal_type, global_ordinal_type, node_type > > &Matrix_in=Teuchos::null)
 Computes the estimated condition number and returns the value.
magnitude_type getCondEst () const
 Returns the computed estimated condition number, or -1.0 if no computed.
Teuchos::RCP< const
Teuchos::Comm< int > > 
getComm () const
 Returns the Tpetra::BlockMap object associated with the range of this matrix operator.
Teuchos::RCP< const
Tpetra::RowMatrix< scalar_type,
local_ordinal_type,
global_ordinal_type, node_type > > 
getMatrix () const
 Returns a reference to the matrix to be preconditioned.
Teuchos::RCP< const MatrixType > getL () const
 Returns a reference to the L factor.
Teuchos::RCP< const MatrixType > getU () const
 Returns a reference to the U factor.
int getNumInitialize () const
 Returns the number of calls to Initialize().
int getNumCompute () const
 Returns the number of calls to Compute().
int getNumApply () const
 Returns the number of calls to apply().
double getInitializeTime () const
 Returns the time spent in Initialize().
double getComputeTime () const
 Returns the time spent in Compute().
double getApplyTime () const
 Returns the time spent in apply().
int getLevelOfFill () const
 The level of fill.
magnitude_type getAbsoluteThreshold () const
 Get absolute threshold value.
magnitude_type getRelativeThreshold () const
 Get relative threshold value.
magnitude_type getRelaxValue () const
 Get the relax value.
magnitude_type getDropTolerance () const
 Gets the dropping tolerance.
global_size_t getGlobalNumEntries () const
 Returns the number of nonzero entries in the global graph.
size_t getNodeNumEntries () const
 Returns the number of nonzero entries in the local graph.
Overridden from Teuchos::Describable
std::string description () const
 Return a simple one-line description of this object.
void describe (Teuchos::FancyOStream &out, const Teuchos::EVerbosityLevel verbLevel=Teuchos::Describable::verbLevel_default) const
 Print the object with some verbosity level to an FancyOStream object.

Typedefs

typedef MatrixType::scalar_type scalar_type
 The type of the entries of the input MatrixType.
typedef
MatrixType::local_ordinal_type 
local_ordinal_type
 The type of local indices in the input MatrixType.
typedef
MatrixType::global_ordinal_type 
global_ordinal_type
 The type of global indices in the input MatrixType.
typedef MatrixType::node_type node_type
 The type of the Kokkos Node used by the input MatrixType.
typedef Teuchos::ScalarTraits
< scalar_type >::magnitudeType 
magnitude_type
 The type of the magnitude (absolute value) of a matrix entry.
TEUCHOS_DEPRECATED typedef
MatrixType::scalar_type 
Scalar
 Preserved only for backwards compatibility. Please use "scalar_type".
TEUCHOS_DEPRECATED typedef
MatrixType::local_ordinal_type 
LocalOrdinal
 Preserved only for backwards compatibility. Please use "local_ordinal_type".
TEUCHOS_DEPRECATED typedef
MatrixType::global_ordinal_type 
GlobalOrdinal
 Preserved only for backwards compatibility. Please use "global_ordinal_type".
TEUCHOS_DEPRECATED typedef
MatrixType::node_type 
Node
 Preserved only for backwards compatibility. Please use "node_type".
TEUCHOS_DEPRECATED typedef
Teuchos::ScalarTraits
< scalar_type >::magnitudeType 
magnitudeType
 Preserved only for backwards compatibility. Please use "magnitude_type".

Detailed Description

template<class MatrixType>
class Ifpack2::ILUT< MatrixType >

ILUT (incomplete LU factorization with threshold) of a Tpetra sparse matrix.

Template Parameters:
Specializationof Tpetra::CrsMatrix or Tpetra::RowMatrix.

This class computes an ILUT sparse incomplete factorization with specified fill and drop tolerance, of a given sparse matrix represented as a Tpetra::RowMatrix.

Warning:
If the matrix is distributed over multiple MPI processes, this class will not work correctly by itself. You must use it as a subdomain solver inside of a domain decomposition method like AdditiveSchwarz (which see). If you use Factory to create an ILUT preconditioner, the Factory will automatically wrap ILUT in AdditiveSchwarz for you, if the matrix's communicator contains multiple processes.

See the documentation of setParameters() for a list of valid parameters.

This version of ILUT is a translation of Aztec's ILUT implementation, which was written by Ray Tuminaro.


Member Typedef Documentation

template<class MatrixType>
typedef MatrixType::scalar_type Ifpack2::ILUT< MatrixType >::scalar_type

The type of the entries of the input MatrixType.

template<class MatrixType>
typedef MatrixType::local_ordinal_type Ifpack2::ILUT< MatrixType >::local_ordinal_type

The type of local indices in the input MatrixType.

template<class MatrixType>
typedef MatrixType::global_ordinal_type Ifpack2::ILUT< MatrixType >::global_ordinal_type

The type of global indices in the input MatrixType.

template<class MatrixType>
typedef MatrixType::node_type Ifpack2::ILUT< MatrixType >::node_type

The type of the Kokkos Node used by the input MatrixType.

template<class MatrixType>
typedef Teuchos::ScalarTraits<scalar_type>::magnitudeType Ifpack2::ILUT< MatrixType >::magnitude_type

The type of the magnitude (absolute value) of a matrix entry.


Constructor & Destructor Documentation

template<class MatrixType >
Ifpack2::ILUT< MatrixType >::ILUT ( const Teuchos::RCP< const Tpetra::RowMatrix< scalar_type, local_ordinal_type, global_ordinal_type, node_type > > &  A) [explicit]

Constructor.

Parameters:
A[in] The sparse matrix to factor, as a Tpetra::RowMatrix. (Tpetra::CrsMatrix inherits from this, so you may use a Tpetra::CrsMatrix here instead.)

The factorization will not modify the input matrix. It stores the L and U factors in the incomplete factorization separately.

template<class MatrixType >
Ifpack2::ILUT< MatrixType >::~ILUT ( ) [virtual]

Destructor.


Member Function Documentation

template<class MatrixType >
void Ifpack2::ILUT< MatrixType >::setParameters ( const Teuchos::ParameterList params) [virtual]

Set preconditioner parameters.

ILUT implements the following parameters:

  • "fact: ilut level-of-fill" (int)
  • "fact: drop tolerance" (magnitude_type)
  • "fact: absolute threshold" (magnitude_type)
  • "fact: relative threshold" (magnitude_type)
  • "fact: relax value" (magnitude_type)

"fact: drop tolerance" is the magnitude threshold for dropping entries. It corresponds to the \(\tau\) parameter in Saad's original description of ILUT. "fact: ilut level-of-fill" is the number of entries to keep in the strict upper triangle of the current row, and in the strict lower triangle of the current row. It corresponds to the \(p\) parameter in Saad's original description. ILUT always keeps the diagonal entry in the current row, regardless of the drop tolerance or fill level.

The absolute and relative threshold parameters affect how this code modifies the diagonal entry of the output factor. These parameters are not part of the original ILUT algorithm, but we include them for consistency with other Ifpack2 preconditioners.

The "fact: relax value" parameter currently has no effect.

Implements Ifpack2::Preconditioner< MatrixType::scalar_type, MatrixType::local_ordinal_type, MatrixType::global_ordinal_type, MatrixType::node_type >.

template<class MatrixType >
void Ifpack2::ILUT< MatrixType >::initialize ( ) [virtual]

Clear any previously computed factors.

You may call this before calling compute(). The compute() method will call this automatically if it has not yet been called. If you call this after calling compute(), you must recompute the factorization (by calling compute() again) before you may call apply().

Implements Ifpack2::Preconditioner< MatrixType::scalar_type, MatrixType::local_ordinal_type, MatrixType::global_ordinal_type, MatrixType::node_type >.

template<class MatrixType>
bool Ifpack2::ILUT< MatrixType >::isInitialized ( ) const [inline, virtual]
template<class MatrixType >
void Ifpack2::ILUT< MatrixType >::compute ( ) [virtual]

Compute factors L and U using the specified diagonal perturbation thresholds and relaxation parameters.

This function computes the ILUT factors L and U using the current:

  1. Value for the drop tolerance
  2. Value for the level of fill
  3. Value for the a priori diagonal threshold values.

Implements Ifpack2::Preconditioner< MatrixType::scalar_type, MatrixType::local_ordinal_type, MatrixType::global_ordinal_type, MatrixType::node_type >.

template<class MatrixType>
bool Ifpack2::ILUT< MatrixType >::isComputed ( ) const [inline, virtual]
template<class MatrixType>
void Ifpack2::ILUT< MatrixType >::apply ( const Tpetra::MultiVector< scalar_type, local_ordinal_type, global_ordinal_type, node_type > &  X,
Tpetra::MultiVector< scalar_type, local_ordinal_type, global_ordinal_type, node_type > &  Y,
Teuchos::ETransp  mode = Teuchos::NO_TRANS,
scalar_type  alpha = Teuchos::ScalarTraitsscalar_type >::one(),
scalar_type  beta = Teuchos::ScalarTraitsscalar_type >::zero() 
) const [virtual]

Returns the result of a ILUT forward/back solve on a Tpetra::MultiVector X in Y.

Parameters:
X- (In) A Tpetra::MultiVector of dimension NumVectors to solve for.
Y- (Out) A Tpetra::MultiVector of dimension NumVectors containing result.

Implements Ifpack2::Preconditioner< MatrixType::scalar_type, MatrixType::local_ordinal_type, MatrixType::global_ordinal_type, MatrixType::node_type >.

template<class MatrixType >
Teuchos::RCP< const Tpetra::Map< typename MatrixType::local_ordinal_type, typename MatrixType::global_ordinal_type, typename MatrixType::node_type > > Ifpack2::ILUT< MatrixType >::getDomainMap ( ) const [virtual]
template<class MatrixType >
Teuchos::RCP< const Tpetra::Map< typename MatrixType::local_ordinal_type, typename MatrixType::global_ordinal_type, typename MatrixType::node_type > > Ifpack2::ILUT< MatrixType >::getRangeMap ( ) const [virtual]
template<class MatrixType >
bool Ifpack2::ILUT< MatrixType >::hasTransposeApply ( ) const

Whether this object's apply() method can apply the transpose (or conjugate transpose, if applicable).

template<class MatrixType>
template<class DomainScalar , class RangeScalar >
void Ifpack2::ILUT< MatrixType >::applyTempl ( const Tpetra::MultiVector< DomainScalar, local_ordinal_type, global_ordinal_type, node_type > &  X,
Tpetra::MultiVector< RangeScalar, local_ordinal_type, global_ordinal_type, node_type > &  Y,
Teuchos::ETransp  mode = Teuchos::NO_TRANS,
RangeScalar  alpha = Teuchos::ScalarTraitsscalar_type >::one(),
RangeScalar  beta = Teuchos::ScalarTraitsscalar_type >::zero() 
) const

Returns the result of a ILUT forward/back solve on a Tpetra::MultiVector X in Y.

Parameters:
X- (In) A Tpetra::MultiVector of dimension NumVectors to solve for.
Y- (Out) A Tpetra::MultiVector of dimension NumVectors containing result.
template<class MatrixType >
ILUT< MatrixType >::magnitude_type Ifpack2::ILUT< MatrixType >::computeCondEst ( CondestType  CT = Cheap,
local_ordinal_type  MaxIters = 1550,
magnitude_type  Tol = 1e-9,
const Teuchos::Ptr< const Tpetra::RowMatrix< scalar_type, local_ordinal_type, global_ordinal_type, node_type > > &  Matrix_in = Teuchos::null 
) [virtual]
template<class MatrixType>
magnitude_type Ifpack2::ILUT< MatrixType >::getCondEst ( ) const [inline, virtual]
template<class MatrixType >
Teuchos::RCP< const Teuchos::Comm< int > > Ifpack2::ILUT< MatrixType >::getComm ( ) const

Returns the Tpetra::BlockMap object associated with the range of this matrix operator.

template<class MatrixType >
Teuchos::RCP< const Tpetra::RowMatrix< typename MatrixType::scalar_type, typename MatrixType::local_ordinal_type, typename MatrixType::global_ordinal_type, typename MatrixType::node_type > > Ifpack2::ILUT< MatrixType >::getMatrix ( ) const [virtual]
template<class MatrixType>
Teuchos::RCP<const MatrixType> Ifpack2::ILUT< MatrixType >::getL ( ) const [inline]

Returns a reference to the L factor.

template<class MatrixType>
Teuchos::RCP<const MatrixType> Ifpack2::ILUT< MatrixType >::getU ( ) const [inline]

Returns a reference to the U factor.

template<class MatrixType >
int Ifpack2::ILUT< MatrixType >::getNumInitialize ( ) const [virtual]
template<class MatrixType >
int Ifpack2::ILUT< MatrixType >::getNumCompute ( ) const [virtual]
template<class MatrixType >
int Ifpack2::ILUT< MatrixType >::getNumApply ( ) const [virtual]
template<class MatrixType >
double Ifpack2::ILUT< MatrixType >::getInitializeTime ( ) const [virtual]
template<class MatrixType >
double Ifpack2::ILUT< MatrixType >::getComputeTime ( ) const [virtual]
template<class MatrixType >
double Ifpack2::ILUT< MatrixType >::getApplyTime ( ) const [virtual]
template<class MatrixType>
int Ifpack2::ILUT< MatrixType >::getLevelOfFill ( ) const [inline]

The level of fill.

For ILUT, this means the maximum number of entries in each row of the resulting L and U factors (each considered separately), not including the diagonal entry in that row (which is always part of U). This has a different meaning for ILUT than it does for ILU(k).

template<class MatrixType>
magnitude_type Ifpack2::ILUT< MatrixType >::getAbsoluteThreshold ( ) const [inline]

Get absolute threshold value.

template<class MatrixType>
magnitude_type Ifpack2::ILUT< MatrixType >::getRelativeThreshold ( ) const [inline]

Get relative threshold value.

template<class MatrixType>
magnitude_type Ifpack2::ILUT< MatrixType >::getRelaxValue ( ) const [inline]

Get the relax value.

template<class MatrixType>
magnitude_type Ifpack2::ILUT< MatrixType >::getDropTolerance ( ) const [inline]

Gets the dropping tolerance.

template<class MatrixType >
global_size_t Ifpack2::ILUT< MatrixType >::getGlobalNumEntries ( ) const

Returns the number of nonzero entries in the global graph.

template<class MatrixType >
size_t Ifpack2::ILUT< MatrixType >::getNodeNumEntries ( ) const

Returns the number of nonzero entries in the local graph.

template<class MatrixType >
std::string Ifpack2::ILUT< MatrixType >::description ( ) const

Return a simple one-line description of this object.

template<class MatrixType >
void Ifpack2::ILUT< MatrixType >::describe ( Teuchos::FancyOStream out,
const Teuchos::EVerbosityLevel  verbLevel = Teuchos::Describable::verbLevel_default 
) const

Print the object with some verbosity level to an FancyOStream object.


Member Data Documentation

template<class MatrixType>
TEUCHOS_DEPRECATED typedef MatrixType::scalar_type Ifpack2::ILUT< MatrixType >::Scalar

Preserved only for backwards compatibility. Please use "scalar_type".

template<class MatrixType>
TEUCHOS_DEPRECATED typedef MatrixType::local_ordinal_type Ifpack2::ILUT< MatrixType >::LocalOrdinal

Preserved only for backwards compatibility. Please use "local_ordinal_type".

template<class MatrixType>
TEUCHOS_DEPRECATED typedef MatrixType::global_ordinal_type Ifpack2::ILUT< MatrixType >::GlobalOrdinal

Preserved only for backwards compatibility. Please use "global_ordinal_type".

template<class MatrixType>
TEUCHOS_DEPRECATED typedef MatrixType::node_type Ifpack2::ILUT< MatrixType >::Node

Preserved only for backwards compatibility. Please use "node_type".

template<class MatrixType>
TEUCHOS_DEPRECATED typedef Teuchos::ScalarTraits<scalar_type>::magnitudeType Ifpack2::ILUT< MatrixType >::magnitudeType

Preserved only for backwards compatibility. Please use "magnitude_type".

Reimplemented from Ifpack2::Preconditioner< MatrixType::scalar_type, MatrixType::local_ordinal_type, MatrixType::global_ordinal_type, MatrixType::node_type >.


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