PreconditionSelector< MatrixType, VectorType > Class Template Reference

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

Inheritance diagram for PreconditionSelector< MatrixType, VectorType >:

Public Types
using	size_type = typename MatrixType::size_type

Public Member Functions
	PreconditionSelector (const std::string &preconditioning, const typename VectorType::value_type &omega=1.)
virtual	~PreconditionSelector () override
void	use_matrix (const MatrixType &M)
size_type	m () const
size_type	n () const
virtual void	vmult (VectorType &dst, const VectorType &src) const
virtual void	Tvmult (VectorType &dst, const VectorType &src) const
template<class Archive >
void	serialize (Archive &ar, const unsigned int version)
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
unsigned int	n_subscriptions () const
template<typename StreamType >
void	list_subscribers (StreamType &stream) const
void	list_subscribers () const

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

Protected Attributes
std::string	preconditioning

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
ObserverPointer< const MatrixType, PreconditionSelector< MatrixType, VectorType > >	A
const VectorType::value_type	omega
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>, typename VectorType = ::Vector<double>>
class PreconditionSelector< MatrixType, VectorType >

Selects the preconditioner. The constructor of this class takes the name of the preconditioning and the damping parameter omega of the preconditioning and the use_matrix function takes the matrix that is used by the matrix-builtin precondition functions. Each time, the operator() function is called, this preselected preconditioner, this matrix and this omega is used for the preconditioning. This class is designed for being used as argument of the solve function of a Solver and it covers the selection of all matrix-builtin precondition functions. The selection of other preconditioners, like BlockSOR or ILU should be handled in derived classes by the user.

Usage

The simplest use of this class is the following:

// generate a @p SolverControl and a @p VectorMemory
SolverControl control;
VectorMemory<Vector<double> > memory;
 
// generate a solver
SolverCG<SparseMatrix<double>, Vector<double> > solver(control, memory);
 
// generate a @p PreconditionSelector
PreconditionSelector<SparseMatrix<double>, Vector<double> >
  preconditioning("jacobi", 1.);
 
// give a matrix whose diagonal entries are to be used for the
// preconditioning. Generally the matrix of the linear equation system Ax=b.
preconditioning.use_matrix(A);
 
// call the @p solve function with this preconditioning as last argument
solver.solve(A,x,b,preconditioning);

The same example where also the SolverSelector class is used reads

// generate a @p SolverControl and a @p VectorMemory
SolverControl control;
VectorMemory<Vector<double> > memory;
 
// generate a @p SolverSelector that calls the @p SolverCG
SolverSelector<SparseMatrix<double>, Vector<double> >
  solver_selector("cg", control, memory);
 
// generate a @p PreconditionSelector
PreconditionSelector<SparseMatrix<double>, Vector<double> >
  preconditioning("jacobi", 1.);
 
preconditioning.use_matrix(A);
 
solver_selector.solve(A,x,b,preconditioning);

Now the use of the SolverSelector in combination with the PreconditionSelector allows the user to select both, the solver and the preconditioner, at the beginning of their program and each time the solver is started (that is several times e.g. in a nonlinear iteration) this preselected solver and preconditioner is called.

Definition at line 100 of file precondition_selector.h.

Member Typedef Documentation

size_type

template<typename MatrixType = SparseMatrix<double>, typename VectorType = ::Vector<double>>

using PreconditionSelector< MatrixType, VectorType >::size_type = typename MatrixType::size_type

Declare type for container size.

Definition at line 106 of file precondition_selector.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 238 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 243 of file enable_observer_pointer.h.

Constructor & Destructor Documentation

PreconditionSelector()

template<typename MatrixType , typename VectorType >

PreconditionSelector< MatrixType, VectorType >::PreconditionSelector	(	const std::string &	preconditioning,
		const typename VectorType::value_type &	omega = 1.
	)

Constructor. omega denotes the damping parameter of the preconditioning.

Definition at line 206 of file precondition_selector.h.

~PreconditionSelector()

template<typename MatrixType , typename VectorType >

PreconditionSelector< MatrixType, VectorType >::~PreconditionSelector ( )

overridevirtual

Destructor.

Definition at line 215 of file precondition_selector.h.

Member Function Documentation

use_matrix()

template<typename MatrixType , typename VectorType >

void PreconditionSelector< MatrixType, VectorType >::use_matrix

(

const MatrixType &

M

)

Takes the matrix that is needed for preconditionings that involves a matrix. e.g. for precondition_jacobi, ~_sor, ~_ssor.

Definition at line 224 of file precondition_selector.h.

m()

template<typename MatrixType , typename VectorType >

PreconditionSelector< MatrixType, VectorType >::size_type PreconditionSelector< MatrixType, VectorType >::m ( ) const

inline

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

Definition at line 232 of file precondition_selector.h.

n()

template<typename MatrixType , typename VectorType >

PreconditionSelector< MatrixType, VectorType >::size_type PreconditionSelector< MatrixType, VectorType >::n ( ) const

inline

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

Definition at line 241 of file precondition_selector.h.

vmult()

template<typename MatrixType , typename VectorType >

void PreconditionSelector< MatrixType, VectorType >::vmult ( VectorType &  dst, const VectorType &  src  ) const

virtual

Precondition procedure. Calls the preconditioning that was specified in the constructor.

Definition at line 251 of file precondition_selector.h.

Tvmult()

template<typename MatrixType , typename VectorType >

void PreconditionSelector< MatrixType, VectorType >::Tvmult ( VectorType &  dst, const VectorType &  src  ) const

virtual

Transpose precondition procedure. Calls the preconditioning that was specified in the constructor.

Definition at line 282 of file precondition_selector.h.

get_precondition_names()

template<typename MatrixType , typename VectorType >

std::string PreconditionSelector< MatrixType, VectorType >::get_precondition_names ( )

static

Get the names of all implemented preconditionings. The list of possible options includes:

• "none"
• "jacobi"
• "sor"
• "ssor"

Definition at line 314 of file precondition_selector.h.

subscribe()

void EnableObserverPointer::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 131 of file enable_observer_pointer.cc.

unsubscribe()

void EnableObserverPointer::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 151 of file enable_observer_pointer.cc.

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 322 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 339 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 331 of file enable_observer_pointer.h.

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

preconditioning

template<typename MatrixType = SparseMatrix<double>, typename VectorType = ::Vector<double>>

std::string PreconditionSelector< MatrixType, VectorType >::preconditioning

protected

Stores the name of the preconditioning.

Definition at line 184 of file precondition_selector.h.

A

template<typename MatrixType = SparseMatrix<double>, typename VectorType = ::Vector<double>>

ObserverPointer<const MatrixType, PreconditionSelector<MatrixType, VectorType> > PreconditionSelector< MatrixType, VectorType >::A

private

Matrix that is used for the matrix-builtin preconditioning function. cf. also PreconditionUseMatrix.

Definition at line 193 of file precondition_selector.h.

omega

template<typename MatrixType = SparseMatrix<double>, typename VectorType = ::Vector<double>>

const VectorType::value_type PreconditionSelector< MatrixType, VectorType >::omega

private

Stores the damping parameter of the preconditioner.

Definition at line 198 of file precondition_selector.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 227 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 233 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 249 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 257 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 280 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_selector.h