TrilinosWrappers::PreconditionILUT Class Reference

#include <deal.II/lac/trilinos_precondition.h>

Inheritance diagram for TrilinosWrappers::PreconditionILUT:

Classes
struct	AdditionalData

Public Member Functions
void	initialize (const SparseMatrix &matrix, const AdditionalData &additional_data=AdditionalData())
Public Member Functions inherited from TrilinosWrappers::PreconditionBase
	PreconditionBase ()
	PreconditionBase (const PreconditionBase &)
	~PreconditionBase ()=default
void	clear ()
MPI_Comm	get_mpi_communicator () const
void	transpose ()
virtual void	vmult (MPI::Vector &dst, const MPI::Vector &src) const
virtual void	Tvmult (MPI::Vector &dst, const MPI::Vector &src) const
virtual void	vmult (::Vector< double > &dst, const ::Vector< double > &src) const
virtual void	Tvmult (::Vector< double > &dst, const ::Vector< double > &src) const
virtual void	vmult (::LinearAlgebra::distributed::Vector< double > &dst, const ::LinearAlgebra::distributed::Vector< double > &src) const
virtual void	Tvmult (::LinearAlgebra::distributed::Vector< double > &dst, const ::LinearAlgebra::distributed::Vector< double > &src) const
Epetra_Operator &	trilinos_operator () const
IndexSet	locally_owned_domain_indices () const
IndexSet	locally_owned_range_indices () const
Public Member Functions inherited from Subscriptor
	Subscriptor ()
	Subscriptor (const Subscriptor &)
	Subscriptor (Subscriptor &&) noexcept
virtual	~Subscriptor ()
Subscriptor &	operator= (const Subscriptor &)
Subscriptor &	operator= (Subscriptor &&) noexcept
void	subscribe (const char *identifier=nullptr) const
void	unsubscribe (const char *identifier=nullptr) const
unsigned int	n_subscriptions () const
void	list_subscribers () const
template<class Archive >
void	serialize (Archive &ar, const unsigned int version)

Additional Inherited Members
Public Types inherited from TrilinosWrappers::PreconditionBase
typedef ::types::global_dof_index	size_type
Static Public Member Functions inherited from TrilinosWrappers::PreconditionBase
static ::ExceptionBase &	ExcNonMatchingMaps (std::string arg1)
Static Public Member Functions inherited from Subscriptor
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)
static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)
Protected Attributes inherited from TrilinosWrappers::PreconditionBase
std::shared_ptr< Epetra_Operator >	preconditioner
Epetra_MpiComm	communicator
std::shared_ptr< Epetra_Map >	vector_distributor

Detailed Description

A wrapper class for a thresholded incomplete LU factorization (ILU-T) preconditioner for Trilinos matrices. This preconditioner works both in serial and in parallel, depending on the matrix it is based on. In general, an incomplete factorization does not take all fill-in elements that would appear in a full factorization (that is the basis for a direct solve). For the ILU-T preconditioner, the parameter ilut_drop lets the user specify which elements should be dropped (i.e., should not be part of the incomplete decomposition). Trilinos calculates first the complete factorization for one row, and then skips those elements that are lower than the threshold. This is the main difference to the non- thresholded ILU preconditioner, where the parameter ilut_fill governs the incomplete factorization structure. This parameter is available here as well, but provides only some extra information here.

The AdditionalData data structure allows to set preconditioner options. Besides the fill-in arguments, these options are some options for perturbations (see the documentation of the AdditionalData structure for details), and a parameter overlap that determines if and how much overlap there should be between the matrix partitions on the various MPI processes. The default settings are 0 for the additional fill-in, 0 for the absolute augmentation tolerance, 1 for the relative augmentation tolerance, 0 for the overlap.

Note that a parallel application of the ILU-T preconditioner is actually a block-Jacobi preconditioner with block size equal to the local matrix size. Spoken more technically, this parallel operation is an additive Schwarz method with an ILU approximate solve as inner solver, based on the (outer) parallel partitioning.

Author

Martin Kronbichler, 2009

Definition at line 1093 of file trilinos_precondition.h.

Member Function Documentation

initialize()

void TrilinosWrappers::PreconditionILUT::initialize	(	const SparseMatrix &	matrix,
		const AdditionalData &	additional_data = AdditionalData()
	)

Initialize function. Takes the matrix which is used to form the preconditioner, and additional flags if there are any.

Definition at line 572 of file trilinos_precondition.cc.

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

• deal.II/lac/trilinos_precondition.h
• source/lac/trilinos_precondition.cc