PreconditionIdentity Class Reference

#include <precondition.h>

Inheritance diagram for PreconditionIdentity:

Classes
struct	AdditionalData

Public Member Functions
template<class MATRIX >
void	initialize (const MATRIX &matrix, const AdditionalData &additional_data=AdditionalData())
template<class VECTOR >
void	vmult (VECTOR &, const VECTOR &) const
template<class VECTOR >
void	Tvmult (VECTOR &, const VECTOR &) const
template<class VECTOR >
void	vmult_add (VECTOR &, const VECTOR &) const
template<class VECTOR >
void	Tvmult_add (VECTOR &, const VECTOR &) const
void	clear ()
Public Member Functions inherited from Subscriptor
	Subscriptor ()
	Subscriptor (const Subscriptor &)
virtual	~Subscriptor ()
Subscriptor &	operator= (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)

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,
          PreconditionIdentity());

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

Definition at line 73 of file precondition.h.

Member Function Documentation

template<class MATRIX >

void PreconditionIdentity::initialize	(	const MATRIX &	matrix,
		const AdditionalData &	additional_data = AdditionalData()
	)

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

template<class VECTOR >

void PreconditionIdentity::vmult	(	VECTOR &	,
		const VECTOR &
	)		const

Apply preconditioner.

template<class VECTOR >

void PreconditionIdentity::Tvmult	(	VECTOR &	,
		const VECTOR &
	)		const

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

template<class VECTOR >

void PreconditionIdentity::vmult_add	(	VECTOR &	,
		const VECTOR &
	)		const

Apply preconditioner, adding to the previous value.

template<class VECTOR >

void PreconditionIdentity::Tvmult_add	(	VECTOR &	,
		const VECTOR &
	)		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 142 of file precondition.h.

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

• include/deal.II/lac/precondition.h