Reference documentation for deal.II version Git 395ab8d 2014-10-31 13:01:43 -0600
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TrilinosWrappers::PreconditionILUT Class Reference

#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 ()
 
void clear ()
 
virtual void vmult (VectorBase &dst, const VectorBase &src) const
 
virtual void Tvmult (VectorBase &dst, const VectorBase &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 (::parallel::distributed::Vector< double > &dst, const ::parallel::distributed::Vector< double > &src) const
 
virtual void Tvmult (::parallel::distributed::Vector< double > &dst, const ::parallel::distributed::Vector< double > &src) const
 
 DeclException1 (ExcNonMatchingMaps, std::string,<< "The sparse matrix the preconditioner is based on "<< "uses a map that is not compatible to the one in vector "<< arg1<< ". Check preconditioner and matrix setup.")
 
- Public Member Functions inherited from Subscriptor
 Subscriptor ()
 
 Subscriptor (const Subscriptor &)
 
virtual ~Subscriptor ()
 
Subscriptoroperator= (const Subscriptor &)
 
void subscribe (const char *identifier=0) const
 
void unsubscribe (const char *identifier=0) const
 
unsigned int n_subscriptions () const
 
void list_subscribers () const
 
 DeclException3 (ExcInUse, int, char *, std::string &,<< "Object of class "<< arg2<< " is still used by "<< arg1<< " other objects.\n"<< "(Additional information: "<< arg3<< ")\n"<< "Note the entry in the Frequently Asked Questions of "<< "deal.II (linked to from http://www.dealii.org/) for "<< "more information on what this error means.")
 
 DeclException2 (ExcNoSubscriber, char *, char *,<< "No subscriber with identifier \""<< arg2<< "\" did subscribe to this object of class "<< arg1)
 
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
 
- Protected Attributes inherited from TrilinosWrappers::PreconditionBase
std_cxx11::shared_ptr
< Epetra_Operator > 
preconditioner
 
Epetra_MpiComm communicator
 
std_cxx11::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 precondtioner, 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 1053 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.


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