PreconditionRichardson Class Reference

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

Inheritance diagram for PreconditionRichardson:

Classes
class	AdditionalData

Public Types
using	size_type = types::global_dof_index

Public Member Functions
	PreconditionRichardson ()
void	initialize (const AdditionalData &parameters)
template<typename MatrixType >
void	initialize (const MatrixType &matrix, const AdditionalData &parameters)
template<typename VectorType >
void	vmult (VectorType &, const VectorType &) const
template<typename VectorType >
void	Tvmult (VectorType &, const VectorType &) const
template<typename VectorType >
void	vmult_add (VectorType &, const VectorType &) const
template<typename VectorType >
void	Tvmult_add (VectorType &, const VectorType &) const
void	clear ()
size_type	m () const
size_type	n () const
template<class Archive >
void	serialize (Archive &ar, const unsigned int version)
Subscriptor functionality
Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.
void	subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
void	unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
unsigned int	n_subscriptions () const
template<typename StreamType >
void	list_subscribers (StreamType &stream) const
void	list_subscribers () const

Static Public Member Functions
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)
static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Private Types
using	map_value_type = decltype(counter_map)::value_type
using	map_iterator = decltype(counter_map)::iterator

Private Member Functions
void	check_no_subscribers () const noexcept

Private Attributes
double	relaxation
size_type	n_rows
size_type	n_columns
std::atomic< unsigned int >	counter
std::map< std::string, unsigned int >	counter_map
std::vector< std::atomic< bool > * >	validity_pointers
const std::type_info *	object_info

Static Private Attributes
static std::mutex	mutex

Detailed Description

Preconditioning with Richardson's method. This preconditioner just scales the vector with a constant relaxation factor provided by the AdditionalData object.

In Krylov-space methods, this preconditioner should not have any effect. Using SolverRichardson, the two relaxation parameters will be just multiplied. Still, this class is useful in multigrid smoother objects (MGSmootherRelaxation).

Definition at line 334 of file precondition.h.

Member Typedef Documentation

size_type

using PreconditionRichardson::size_type = types::global_dof_index

Declare type for container size.

Definition at line 340 of file precondition.h.

map_value_type

using Subscriptor::map_value_type = decltype(counter_map)::value_type

privateinherited

The data type used in counter_map.

Definition at line 229 of file subscriptor.h.

map_iterator

using Subscriptor::map_iterator = decltype(counter_map)::iterator

privateinherited

The iterator type used in counter_map.

Definition at line 234 of file subscriptor.h.

Constructor & Destructor Documentation

PreconditionRichardson()

PreconditionRichardson::PreconditionRichardson

(

)

Constructor, sets the relaxation parameter, domain and range sizes to their default.

Member Function Documentation

initialize() [1/2]

void PreconditionRichardson::initialize

(

const AdditionalData &

parameters

)

Change the relaxation parameter.

initialize() [2/2]

template<typename MatrixType >

void PreconditionRichardson::initialize	(	const MatrixType &	matrix,
		const AdditionalData &	parameters )

Change the relaxation parameter in a way consistent with other preconditioners. The matrix argument is ignored and here just for compatibility with more complex preconditioners.

vmult()

template<typename VectorType >

void PreconditionRichardson::vmult	(	VectorType &	,
		const VectorType &	) const

Apply preconditioner.

Tvmult()

template<typename VectorType >

void PreconditionRichardson::Tvmult	(	VectorType &	,
		const VectorType &	) const

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

vmult_add()

template<typename VectorType >

void PreconditionRichardson::vmult_add	(	VectorType &	,
		const VectorType &	) const

Apply preconditioner, adding to the previous value.

Tvmult_add()

template<typename VectorType >

void PreconditionRichardson::Tvmult_add	(	VectorType &	,
		const VectorType &	) const

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

clear()

void PreconditionRichardson::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 415 of file precondition.h.

m()

size_type PreconditionRichardson::m

(

)

const

Return the dimension of the codomain (or range) space. Note that the matrix is of dimension \(m \times n\).

Note

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

n()

size_type PreconditionRichardson::n

(

)

const

Return the dimension of the domain space. Note that the matrix is of dimension \(m \times n\).

Note

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

subscribe()

void Subscriptor::subscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const

inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 135 of file subscriptor.cc.

unsubscribe()

void Subscriptor::unsubscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const

inherited

Unsubscribes a user from the object.

Note

The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 155 of file subscriptor.cc.

n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const

inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

list_subscribers() [1/2]

template<typename StreamType >

void Subscriptor::list_subscribers ( StreamType & stream ) const

inlineinherited

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 203 of file subscriptor.cc.

serialize()

template<class Archive >

void Subscriptor::serialize ( Archive & ar, const unsigned int version )

inlineinherited

Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 309 of file subscriptor.h.

check_no_subscribers()

void Subscriptor::check_no_subscribers ( ) const

privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note

Since this function is just a consistency check it does nothing in release mode.

If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 52 of file subscriptor.cc.

Member Data Documentation

relaxation

double PreconditionRichardson::relaxation

private

The relaxation parameter multiplied with the vectors.

Definition at line 442 of file precondition.h.

n_rows

size_type PreconditionRichardson::n_rows

private

The dimension of the range space.

Definition at line 447 of file precondition.h.

n_columns

size_type PreconditionRichardson::n_columns

private

The dimension of the domain space.

Definition at line 452 of file precondition.h.

counter

std::atomic<unsigned int> Subscriptor::counter

mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 218 of file subscriptor.h.

counter_map

std::map<std::string, unsigned int> Subscriptor::counter_map

mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 224 of file subscriptor.h.

validity_pointers

std::vector<std::atomic<bool> *> Subscriptor::validity_pointers

mutableprivateinherited

In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.

Definition at line 240 of file subscriptor.h.

object_info

const std::type_info* Subscriptor::object_info

mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 248 of file subscriptor.h.

mutex

std::mutex Subscriptor::mutex

staticprivateinherited

A mutex used to ensure data consistency when accessing the mutable members of this class. This lock is used in the subscribe() and unsubscribe() functions, as well as in list_subscribers().

Definition at line 271 of file subscriptor.h.

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

• include/deal.II/lac/precondition.h