Reference documentation for deal.II version Git 36a2878 2015-07-07 14:20:53 -0600
PreconditionChebyshev< MATRIX, VECTOR > Class Template Reference

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

Inheritance diagram for PreconditionChebyshev< MATRIX, VECTOR >:
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## Public Types

typedef types::global_dof_index size_type

## Public Member Functions

void vmult (VECTOR &dst, const VECTOR &src) const

void Tvmult (VECTOR &dst, const VECTOR &src) const

void clear ()

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

SmartPointer< const MATRIX, PreconditionChebyshev< MATRIX, VECTOR > > matrix_ptr

VECTOR update1

VECTOR update2

double theta

double delta

bool is_initialized

## Detailed Description

### template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>> class PreconditionChebyshev< MATRIX, VECTOR >

Preconditioning with a Chebyshev polynomial for symmetric positive definite matrices. This preconditioner is similar to a Jacobi preconditioner if the degree variable is set to one, otherwise some higher order polynomial corrections are used. This preconditioner needs access to the diagonal of the matrix its acts on and needs a respective vmult implemention. However, it does not need to explicitly know the matrix entries.

This class is useful e.g. in multigrid smoother objects, since it is trivially parallel (assuming that matrix-vector products are parallel).

Definition at line 663 of file precondition.h.

## Member Typedef Documentation

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 typedef types::global_dof_index PreconditionChebyshev< MATRIX, VECTOR >::size_type

Declare type for container size.

Definition at line 669 of file precondition.h.

## Member Function Documentation

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 void PreconditionChebyshev< MATRIX, VECTOR >::initialize ( const MATRIX & 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. This function works only if the input matrix has an operator el(i,i) for accessing all the elements in the diagonal. Alternatively, the diagonal can be supplied with the help of the AdditionalData field.

This function calculates an estimate of the eigenvalue range of the matrix weighted by its diagonal using a modified CG iteration in case the given number of iterations is positive.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 void PreconditionChebyshev< MATRIX, VECTOR >::vmult ( VECTOR & dst, const VECTOR & src ) const

Computes the action of the preconditioner on src, storing the result in dst.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 void PreconditionChebyshev< MATRIX, VECTOR >::Tvmult ( VECTOR & dst, const VECTOR & src ) const

Computes the action of the transposed preconditioner on src, storing the result in dst.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 void PreconditionChebyshev< MATRIX, VECTOR >::clear ( )

Resets the preconditioner.

## Member Data Documentation

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 SmartPointer > PreconditionChebyshev< MATRIX, VECTOR >::matrix_ptr
private

A pointer to the underlying matrix.

Definition at line 785 of file precondition.h.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 VECTOR PreconditionChebyshev< MATRIX, VECTOR >::update1
mutableprivate

Internal vector used for the vmult operation.

Definition at line 790 of file precondition.h.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 VECTOR PreconditionChebyshev< MATRIX, VECTOR >::update2
mutableprivate

Internal vector used for the vmult operation.

Definition at line 795 of file precondition.h.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
private

Stores the additional data provided to the initialize function.

Definition at line 800 of file precondition.h.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 double PreconditionChebyshev< MATRIX, VECTOR >::theta
private

Average of the largest and smallest eigenvalue under consideration.

Definition at line 805 of file precondition.h.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 double PreconditionChebyshev< MATRIX, VECTOR >::delta
private

Half the interval length between the largest and smallest eigenvalue under consideration.

Definition at line 811 of file precondition.h.

template<class MATRIX = SparseMatrix<double>, class VECTOR = Vector<double>>
 bool PreconditionChebyshev< MATRIX, VECTOR >::is_initialized
private

Stores whether the preconditioner has been set up.

Definition at line 816 of file precondition.h.

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