Reference documentation for deal.II version Git d4d2cec 2016-02-13 15:55:06 -0600
Classes | Public Types | Public Member Functions | Private Attributes | List of all members

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

Inheritance diagram for PreconditionIdentity:
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Classes

struct  AdditionalData
 

Public Types

typedef types::global_dof_index size_type
 

Public Member Functions

 PreconditionIdentity ()
 
template<typename MatrixType >
void initialize (const MatrixType &matrix, const AdditionalData &additional_data=AdditionalData())
 
template<class VectorType >
void vmult (VectorType &, const VectorType &) const
 
template<class VectorType >
void Tvmult (VectorType &, const VectorType &) const
 
template<class VectorType >
void vmult_add (VectorType &, const VectorType &) const
 
template<class VectorType >
void Tvmult_add (VectorType &, const VectorType &) const
 
void clear ()
 
size_type m () const
 
size_type n () const
 
- 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\n"<< "(Additional information: "<< arg3<< ")\n\n"<< "See the entry in the Frequently Asked Questions of "<< "deal.II (linked to from http://www.dealii.org/) for "<< "a lot more information on what this error means and "<< "how to fix programs in which it happens.")
 
 DeclException2 (ExcNoSubscriber, char *, char *,<< "No subscriber with identifier <"<< arg2<< "> subscribes to this object of class "<< arg1<< ". Consequently, it cannot be unsubscribed.")
 
template<class Archive >
void serialize (Archive &ar, const unsigned int version)
 

Private Attributes

size_type n_rows
 
size_type n_columns
 

Detailed Description

No preconditioning. This class helps you, if you want to use a linear solver without preconditioning. All solvers in LAC require a preconditioner. Therefore, you must use the identity provided here to avoid preconditioning. It can be used in the following way:

SolverControl solver_control (1000, 1e-12);
SolverCG<> cg (solver_control);
cg.solve (system_matrix, solution, system_rhs,

See the step-3 tutorial program for an example and additional explanations.

Alternatively, the IdentityMatrix class can be used to precondition in this way.

Author
Guido Kanschat, 1999; extension for full compatibility with LinearOperator class: Jean-Paul Pelteret, 2015

Definition at line 72 of file precondition.h.

Member Typedef Documentation

Declare type for container size.

Definition at line 78 of file precondition.h.

Constructor & Destructor Documentation

PreconditionIdentity::PreconditionIdentity ( )

Constructor, sets the domain and range sizes to their defaults.

Member Function Documentation

template<typename MatrixType >
void PreconditionIdentity::initialize ( const MatrixType &  matrix,
const AdditionalData additional_data = AdditionalData() 
)

The matrix argument is ignored and here just for compatibility with more complex preconditioners.

template<class VectorType >
void PreconditionIdentity::vmult ( VectorType &  ,
const VectorType &   
) const

Apply preconditioner.

template<class VectorType >
void PreconditionIdentity::Tvmult ( VectorType &  ,
const VectorType &   
) const

Apply transpose preconditioner. Since this is the identity, this function is the same as vmult().

template<class VectorType >
void PreconditionIdentity::vmult_add ( VectorType &  ,
const VectorType &   
) const

Apply preconditioner, adding to the previous value.

template<class VectorType >
void PreconditionIdentity::Tvmult_add ( VectorType &  ,
const VectorType &   
) const

Apply transpose preconditioner, adding. Since this is the identity, this function is the same as vmult_add().

void PreconditionIdentity::clear ( )
inline

This function is only present to provide the interface of a preconditioner to be handed to a smoother. This does nothing.

Definition at line 135 of file precondition.h.

size_type PreconditionIdentity::m ( ) const

Return the dimension of the codomain (or range) space. To remember: the matrix is of dimension \(m \times n\).

Note
This function should only be called if the preconditioner has been initialized.
size_type PreconditionIdentity::n ( ) const

Return the dimension of the domain space. To remember: the matrix is of dimension \(m \times n\).

Note
This function should only be called if the preconditioner has been initialized.

Member Data Documentation

size_type PreconditionIdentity::n_rows
private

The dimension of the range space.

Definition at line 159 of file precondition.h.

size_type PreconditionIdentity::n_columns
private

The dimension of the domain space.

Definition at line 164 of file precondition.h.


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