PreconditionSOR< MatrixType > Class Template Reference

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

Inheritance diagram for PreconditionSOR< MatrixType >:

Public Types
using	AdditionalData = typename BaseClass::AdditionalData
using	size_type = types::global_dof_index
using	EigenvalueInformation = internal::EigenvalueInformation

Public Member Functions
void	initialize (const MatrixType &A, const AdditionalData &parameters=AdditionalData())
void	clear ()
size_type	m () const
size_type	n () const
template<typename VectorType >
void	vmult (VectorType &, const VectorType &) const
template<typename VectorType >
void	Tvmult (VectorType &, const VectorType &) const
template<typename VectorType >
void	step (VectorType &x, const VectorType &rhs) const
template<typename VectorType >
void	Tstep (VectorType &x, const VectorType &rhs) const
template<typename VectorType >
EigenvalueInformation	estimate_eigenvalues (const VectorType &src) const
double	get_relaxation () const
template<class Archive >
void	serialize (Archive &ar, const unsigned int version)
Querying the observer pointers an object has.
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)

Protected Attributes
ObserverPointer< const MatrixType, PreconditionRelaxation< MatrixType > >	A
AdditionalData	data
std::shared_ptr< PreconditionerType >	preconditioner
bool	eigenvalues_are_initialized

Private Types
using	PreconditionerType = internal::PreconditionRelaxation::PreconditionSORImpl< MatrixType >
using	BaseClass = PreconditionRelaxation< MatrixType, PreconditionerType >
using	map_value_type = decltype(counter_map)::value_type
using	map_iterator = decltype(counter_map)::iterator

Private Member Functions
EnableObserverPointer functionality
Classes derived from EnableObserverPointer provide a facility to subscribe to this object. This is mostly used by the ObserverPointer 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
void	check_no_subscribers () const noexcept

Private Attributes
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

template<typename MatrixType = SparseMatrix<double>>
class PreconditionSOR< MatrixType >

SOR preconditioner using matrix built-in function.

Assuming the matrix A = D + L + U is split into its diagonal D as well as the strict lower and upper triangles L and U, then the SOR preconditioner with relaxation parameter r is

\[ P^{-1} = r (D+rL)^{-1}. \]

It is this operator P^-1, which is implemented by vmult() through forward substitution. Analogously, Tvmult() implements the operation of r(D+rU)^-1.

The SOR iteration itself can be directly written as

\[ x^{k+1} = x^k - r D^{-1} \bigl(L x^{k+1} + U x^k - b\bigr). \]

Using the right hand side b and the previous iterate x, this is the operation implemented by step().

The MatrixType class used is required to have functions precondition_SOR(VectorType&, const VectorType&, double) and precondition_TSOR(VectorType&, const VectorType&, double). This class satisfies the relaxation concept.

// Declare related objects
 
SparseMatrix<double> A;
Vector<double> x;
Vector<double> b;
SolverCG<> solver(...);
 
//...initialize and build A
 
// Define and initialize preconditioner
 
PreconditionSOR<SparseMatrix<double> > precondition;
precondition.initialize(
  A, PreconditionSOR<SparseMatrix<double>>::AdditionalData(.6));
 
solver.solve (A, x, b, precondition);

Definition at line 1711 of file precondition.h.

Member Typedef Documentation

PreconditionerType

template<typename MatrixType = SparseMatrix<double>>

using PreconditionSOR< MatrixType >::PreconditionerType = internal::PreconditionRelaxation::PreconditionSORImpl<MatrixType>

private

Definition at line 1716 of file precondition.h.

BaseClass

template<typename MatrixType = SparseMatrix<double>>

using PreconditionSOR< MatrixType >::BaseClass = PreconditionRelaxation<MatrixType, PreconditionerType>

private

Definition at line 1718 of file precondition.h.

AdditionalData

template<typename MatrixType = SparseMatrix<double>>

using PreconditionSOR< MatrixType >::AdditionalData = typename BaseClass::AdditionalData

An alias to the base class AdditionalData.

Definition at line 1724 of file precondition.h.

size_type

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

using PreconditionRelaxation< MatrixType, PreconditionerType >::size_type = types::global_dof_index

inherited

Declare type for container size.

Definition at line 571 of file precondition.h.

EigenvalueInformation

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

using PreconditionRelaxation< MatrixType, PreconditionerType >::EigenvalueInformation = internal::EigenvalueInformation

inherited

Definition at line 664 of file precondition.h.

map_value_type

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

privateinherited

The data type used in counter_map.

Definition at line 223 of file enable_observer_pointer.h.

map_iterator

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

privateinherited

The iterator type used in counter_map.

Definition at line 228 of file enable_observer_pointer.h.

Member Function Documentation

initialize()

template<typename MatrixType = SparseMatrix<double>>

void PreconditionSOR< MatrixType >::initialize	(	const MatrixType &	A,
		const AdditionalData &	parameters = AdditionalData()
	)

Initialize matrix and relaxation parameter. The matrix is just stored in the preconditioner object. The relaxation parameter should be larger than zero and smaller than 2 for numerical reasons. It defaults to 1.

clear()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

void PreconditionRelaxation< MatrixType, PreconditionerType >::clear ( )

inherited

Release the matrix and reset its pointer.

m()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

size_type PreconditionRelaxation< MatrixType, PreconditionerType >::m ( ) const

inherited

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

n()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

size_type PreconditionRelaxation< MatrixType, PreconditionerType >::n ( ) const

inherited

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

vmult()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

template<typename VectorType >

void PreconditionRelaxation< MatrixType, PreconditionerType >::vmult ( VectorType &  , const VectorType &    ) const

inherited

Apply preconditioner.

Tvmult()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

template<typename VectorType >

void PreconditionRelaxation< MatrixType, PreconditionerType >::Tvmult ( VectorType &  , const VectorType &    ) const

inherited

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

step()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

template<typename VectorType >

void PreconditionRelaxation< MatrixType, PreconditionerType >::step ( VectorType &  x, const VectorType &  rhs  ) const

inherited

Perform one step of the preconditioned Richardson iteration

Tstep()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

template<typename VectorType >

void PreconditionRelaxation< MatrixType, PreconditionerType >::Tstep ( VectorType &  x, const VectorType &  rhs  ) const

inherited

Perform one transposed step of the preconditioned Richardson iteration.

estimate_eigenvalues()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

template<typename VectorType >

EigenvalueInformation PreconditionRelaxation< MatrixType, PreconditionerType >::estimate_eigenvalues ( const VectorType &  src ) const

inherited

Estimate eigenvalues and set relaxation parameter.

get_relaxation()

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

double PreconditionRelaxation< MatrixType, PreconditionerType >::get_relaxation ( ) const

inherited

Return the relaxation parameter. This function also allows to return the parameter in case it was internally determined by running an eigenvalue algorithm.

n_subscriptions()

unsigned int EnableObserverPointer::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 339 of file enable_observer_pointer.h.

list_subscribers() [1/2]

template<typename StreamType >

void EnableObserverPointer::list_subscribers ( StreamType &  stream ) const

inlineinherited

List the subscribers to the input stream.

Definition at line 356 of file enable_observer_pointer.h.

list_subscribers() [2/2]

void EnableObserverPointer::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 199 of file enable_observer_pointer.cc.

serialize()

template<class Archive >

void EnableObserverPointer::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 348 of file enable_observer_pointer.h.

subscribe()

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

privateinherited

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

Definition at line 131 of file enable_observer_pointer.cc.

unsubscribe()

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

privateinherited

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 151 of file enable_observer_pointer.cc.

check_no_subscribers()

void EnableObserverPointer::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 53 of file enable_observer_pointer.cc.

Member Data Documentation

A

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

ObserverPointer<const MatrixType, PreconditionRelaxation<MatrixType> > PreconditionRelaxation< MatrixType, PreconditionerType >::A

protectedinherited

Pointer to the matrix object.

Definition at line 685 of file precondition.h.

data

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

AdditionalData PreconditionRelaxation< MatrixType, PreconditionerType >::data

protectedinherited

Stores the additional data passed to the initialize function, obtained through a copy operation.

Definition at line 691 of file precondition.h.

preconditioner

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

std::shared_ptr<PreconditionerType> PreconditionRelaxation< MatrixType, PreconditionerType >::preconditioner

protectedinherited

Preconditioner.

Definition at line 696 of file precondition.h.

eigenvalues_are_initialized

template<typename MatrixType = SparseMatrix<double>, typename PreconditionerType = IdentityMatrix>

bool PreconditionRelaxation< MatrixType, PreconditionerType >::eigenvalues_are_initialized

protectedinherited

Stores whether the preconditioner has been set up and eigenvalues have been computed.

Definition at line 702 of file precondition.h.

counter

std::atomic<unsigned int> EnableObserverPointer::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 212 of file enable_observer_pointer.h.

counter_map

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

mutableprivateinherited

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

Definition at line 218 of file enable_observer_pointer.h.

validity_pointers

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

mutableprivateinherited

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

Definition at line 234 of file enable_observer_pointer.h.

object_info

const std::type_info* EnableObserverPointer::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 242 of file enable_observer_pointer.h.

mutex

std::mutex EnableObserverPointer::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 249 of file enable_observer_pointer.h.

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

• include/deal.II/lac/precondition.h