Reference documentation for deal.II version 9.1.0-pre
Classes | Public Member Functions | List of all members
TrilinosWrappers::PreconditionILUT Class Reference
Linear algebra classes » TrilinosWrappersLinear algebra classesLinear algebra classes » | Matrix classes » | Preconditioners and Relaxation Operators

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

Inheritance diagram for TrilinosWrappers::PreconditionILUT:
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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 () override=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
 
template<typename StreamType >
void list_subscribers (StreamType &stream) 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
using size_type = ::types::global_dof_index
 
- 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 1097 of file trilinos_precondition.h.

Member Function Documentation

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 580 of file trilinos_precondition.cc.

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