#include <deal.II/multigrid/mg_smoother.h>

Inheritance diagram for mg::SmootherRelaxation< RelaxationType, VectorType >:

Public Member Functions
	SmootherRelaxation (const unsigned int steps=1, const bool variable=false, const bool symmetric=false, const bool transpose=false)

template<typename MatrixType2 >
void	initialize (const MGLevelObject< MatrixType2 > &matrices, const typename RelaxationType::AdditionalData &additional_data=typename RelaxationType::AdditionalData())

template<typename MatrixType2 , class DATA >
void	initialize (const MGLevelObject< MatrixType2 > &matrices, const MGLevelObject< DATA > &additional_data)

void	clear () override

virtual void	smooth (const unsigned int level, VectorType &u, const VectorType &rhs) const override

virtual void	apply (const unsigned int level, VectorType &u, const VectorType &rhs) const override

std::size_t	memory_consumption () const

RelaxationType &	operator[] (const unsigned int level)

const RelaxationType &	operator[] (const unsigned int level) const

const RelaxationType &	back () const

void	resize (const unsigned int new_minlevel, const unsigned int new_maxlevel, Args &&...args)

void	clear_elements ()

unsigned int	min_level () const

unsigned int	max_level () const

unsigned int	n_levels () const

void	apply (ActionFunctionObjectType action)

template<class Archive >
void	serialize (Archive &ar, const unsigned int version)

void	set_steps (const unsigned int)

void	set_variable (const bool)

void	set_symmetric (const bool)

void	set_transpose (const bool)

void	set_debug (const unsigned int level)

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

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)

static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Protected Attributes
GrowingVectorMemory< VectorType >	vector_memory

unsigned int	steps

bool	variable

bool	symmetric

bool	transpose

unsigned int	debug

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
unsigned int	minlevel

std::vector< std::shared_ptr< RelaxationType > >	objects

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<class RelaxationType, typename VectorType>
class mg::SmootherRelaxation< RelaxationType, VectorType >

Smoother using relaxation classes.

A relaxation class is an object that satisfies the relaxation concept.

This class performs smoothing on each level. The operation can be controlled by several parameters. First, the relaxation parameter omega is used in the underlying relaxation method. steps is the number of relaxation steps on the finest level (on all levels if variable is off). If variable is true, the number of smoothing steps is doubled on each coarser level. This results in a method having the complexity of the W-cycle, but saving grid transfers. This is the method proposed by Bramble at al.

The option symmetric switches on alternating between the smoother and its transpose in each step as proposed by Bramble.

transpose uses the transposed smoothing operation using Tstep instead of the regular step of the relaxation scheme.

If you are using block matrices, the second initialize function offers the possibility to extract a single block for smoothing. In this case, the multigrid method must be used only with the vector associated to that single block.

Definition at line 185 of file mg_smoother.h.

Member Typedef Documentation

◆ map_value_type

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

privateinherited

The data type used in counter_map.

Definition at line 230 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 235 of file subscriptor.h.

Constructor & Destructor Documentation

◆ SmootherRelaxation()

template<class RelaxationType , typename VectorType >

mg::SmootherRelaxation< RelaxationType, VectorType >::SmootherRelaxation	(	const unsigned int	steps = `1`,
		const bool	variable = `false`,
		const bool	symmetric = `false`,
		const bool	transpose = `false`
	)

Constructor. Sets smoothing parameters.

Member Function Documentation

◆ initialize() [1/2]

template<class RelaxationType , typename VectorType >

template<typename MatrixType2 >

void mg::SmootherRelaxation< RelaxationType, VectorType >::initialize	(	const MGLevelObject< MatrixType2 > &	matrices,
		const typename RelaxationType::AdditionalData &	additional_data = `typename RelaxationType::AdditionalData()`
	)

Initialize for matrices. This function initializes the smoothing operator with the same smoother for each level.

additional_data is an object of type RelaxationType::AdditionalData and is handed to the initialization function of the relaxation method.

◆ initialize() [2/2]

template<class RelaxationType , typename VectorType >

template<typename MatrixType2 , class DATA >

void mg::SmootherRelaxation< RelaxationType, VectorType >::initialize	(	const MGLevelObject< MatrixType2 > &	matrices,
		const MGLevelObject< DATA > &	additional_data
	)

Initialize matrices and additional data for each level.

If minimal or maximal level of the two objects differ, the greatest common range is utilized. This way, smoothing can be restricted to certain levels even if the matrix was generated for all levels.

◆ clear()

template<class RelaxationType , typename VectorType >

void mg::SmootherRelaxation< RelaxationType, VectorType >::clear ( )

overridevirtual

Empty all vectors.

Implements MGSmootherBase< VectorType >.

◆ smooth()

template<class RelaxationType , typename VectorType >

virtual void mg::SmootherRelaxation< RelaxationType, VectorType >::smooth	(	const unsigned int	level,
		VectorType &	u,
		const VectorType &	rhs
	)		const

overridevirtual

The actual smoothing method.

Implements MGSmootherBase< VectorType >.

◆ apply() [1/2]

template<class RelaxationType , typename VectorType >

virtual void mg::SmootherRelaxation< RelaxationType, VectorType >::apply	(	const unsigned int	level,
		VectorType &	u,
		const VectorType &	rhs
	)		const

overridevirtual

The apply variant of smoothing, setting the vector u to zero before calling the smooth function. This function is equivalent to the following code

u = 0;

smooth(level, u, rhs);

mg::SmootherRelaxation::smooth

virtual void smooth(const unsigned int level, VectorType &u, const VectorType &rhs) const override

level

unsigned int level

Definition grid_out.cc:4618

In the multigrid preconditioner interfaces, the apply() method is used for the pre-smoothing operation because the previous content in the solution vector needs to be overwritten for a new incoming residual. On the other hand, all subsequent operations need to smooth the content already present in the vector u given the right hand side, which is done by smooth().

Reimplemented from MGSmootherBase< VectorType >.

◆ memory_consumption()

template<class RelaxationType , typename VectorType >

std::size_t mg::SmootherRelaxation< RelaxationType, VectorType >::memory_consumption ( ) const

Memory used by this object.

◆ operator[]() [1/2]

RelaxationType & MGLevelObject< RelaxationType >::operator[] ( const unsigned int level )

inherited

Access object on level level.

Definition at line 89 of file mg_level_object.h.

◆ operator[]() [2/2]

const RelaxationType & MGLevelObject< RelaxationType >::operator[] ( const unsigned int level ) const

inherited

Access object on level level.

This function can be called on a const object, and consequently returns a const reference.

Definition at line 98 of file mg_level_object.h.

◆ back()

const RelaxationType & MGLevelObject< RelaxationType >::back

inherited

Return object on level max.

Definition at line 104 of file mg_level_object.h.

◆ resize()

void MGLevelObject< RelaxationType >::resize	(	const unsigned int	new_minlevel,
		const unsigned int	new_maxlevel,
		Args &&...	args
	)

inherited

Delete all previous contents of this object and reset its size according to the values of new_minlevel and new_maxlevel.

Parameters

[in]	new_minlevel	The lowest level for which to provision memory for level objects.
[in]	new_maxlevel	The highest level for which to provision memory for level objects.
[in]	args	Optional arguments passed to the constructor of the underlying object.

Precondition: minlevel <= maxlevel

Definition at line 121 of file mg_level_object.h.

◆ clear_elements()

void MGLevelObject< RelaxationType >::clear_elements

inherited

Call clear on all objects stored by this object. This function is only implemented for some Object classes, e.g., matrix types or the PreconditionBlockSOR and similar classes. Using this function will fail with a compiler error if the Object template type to this class does not provide a clear() member function.

Definition at line 143 of file mg_level_object.h.

◆ min_level()

unsigned int MGLevelObject< RelaxationType >::min_level

inherited

The coarsest level for which this class stores a level object.

Definition at line 149 of file mg_level_object.h.

◆ max_level()

unsigned int MGLevelObject< RelaxationType >::max_level

inherited

The highest level for which this class stores a level object.

Definition at line 155 of file mg_level_object.h.

◆ n_levels()

unsigned int MGLevelObject< RelaxationType >::n_levels

inherited

Number of levels, i.e., max_level()-min_level()+1.

Definition at line 161 of file mg_level_object.h.

◆ apply() [2/2]

void MGLevelObject< RelaxationType >::apply ( ActionFunctionObjectType action )

inherited

Apply the action action to every object stored in here. The parameter action is expected to be a function object that accepts the syntax action(const unsigned int level, Object &object); This means this function can accept a lambda, a std::function, or a plain function pointer.

Definition at line 175 of file mg_level_object.h.

◆ subscribe() [1/2]

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 136 of file subscriptor.cc.

◆ unsubscribe() [1/2]

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 156 of file subscriptor.cc.

◆ n_subscriptions() [1/2]

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() [1/4]

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() [2/4]

void Subscriptor::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

◆ serialize() [1/2]

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 53 of file subscriptor.cc.

◆ set_steps()

template<typename VectorType >

void MGSmoother< VectorType >::set_steps ( const unsigned int )

inherited

Modify the number of smoothing steps on finest level.

◆ set_variable()

template<typename VectorType >

void MGSmoother< VectorType >::set_variable ( const bool )

inherited

Switch on/off variable smoothing.

◆ set_symmetric()

template<typename VectorType >

void MGSmoother< VectorType >::set_symmetric ( const bool )

inherited

Switch on/off symmetric smoothing.

◆ set_transpose()

template<typename VectorType >

void MGSmoother< VectorType >::set_transpose ( const bool )

inherited

Switch on/off transposed smoothing. The effect is overridden by set_symmetric().

◆ set_debug()

template<typename VectorType >

void MGSmoother< VectorType >::set_debug ( const unsigned int level )

inherited

Set debug to a nonzero value to get debug information logged to deallog. Increase to get more information

◆ subscribe() [2/2]

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 136 of file subscriptor.cc.

◆ unsubscribe() [2/2]

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 156 of file subscriptor.cc.

◆ n_subscriptions() [2/2]

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() [3/4]

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() [4/4]

void Subscriptor::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

◆ serialize() [2/2]

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.

Member Data Documentation

◆ minlevel

unsigned int MGLevelObject< RelaxationType >::minlevel

privateinherited

Level of first component.

Definition at line 187 of file mg_level_object.h.

◆ objects

std::vector<std::shared_ptr<RelaxationType > > MGLevelObject< RelaxationType >::objects

privateinherited

Array of the objects to be held.

Definition at line 192 of file mg_level_object.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 219 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 225 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 241 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 249 of file subscriptor.h.

◆ mutex

std::mutex Subscriptor::mutex

staticprivateinherited

A mutex used to ensure data consistency when printing out the list of subscribers.

Definition at line 271 of file subscriptor.h.

◆ vector_memory

template<typename VectorType >

GrowingVectorMemory<VectorType> MGSmoother< VectorType >::vector_memory

mutableprotectedinherited

A memory object to be used for temporary vectors.

The object is marked as mutable since we will need to use it to allocate temporary vectors also in functions that are const.

Definition at line 100 of file mg_smoother.h.

◆ steps

template<typename VectorType >

unsigned int MGSmoother< VectorType >::steps

protectedinherited

Number of smoothing steps on the finest level. If no variable smoothing is chosen, this is the number of steps on all levels.

Definition at line 106 of file mg_smoother.h.

◆ variable

template<typename VectorType >

bool MGSmoother< VectorType >::variable

protectedinherited

Variable smoothing: double the number of smoothing steps whenever going to the next coarser level

Definition at line 112 of file mg_smoother.h.

◆ symmetric

template<typename VectorType >

bool MGSmoother< VectorType >::symmetric

protectedinherited

Symmetric smoothing: in the smoothing iteration, alternate between the relaxation method and its transpose.

Definition at line 118 of file mg_smoother.h.

◆ transpose

template<typename VectorType >

bool MGSmoother< VectorType >::transpose

protectedinherited

Use the transpose of the relaxation method instead of the method itself. This has no effect if symmetric smoothing is chosen.

Definition at line 124 of file mg_smoother.h.

◆ debug

template<typename VectorType >

unsigned int MGSmoother< VectorType >::debug

protectedinherited

Output debugging information to deallog if this is nonzero.

Definition at line 129 of file mg_smoother.h.

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

include/deal.II/multigrid/mg_smoother.h

Public Member Functions

Static Public Member Functions

Protected Attributes

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Member Typedef Documentation

◆ map_value_type

◆ map_iterator

Constructor & Destructor Documentation

◆ SmootherRelaxation()

Member Function Documentation

◆ initialize() [1/2]

◆ initialize() [2/2]

◆ clear()

◆ smooth()

◆ apply() [1/2]

◆ memory_consumption()

◆ operator[]() [1/2]

◆ operator[]() [2/2]

◆ back()

◆ resize()

◆ clear_elements()

◆ min_level()

◆ max_level()

◆ n_levels()

◆ apply() [2/2]

◆ subscribe() [1/2]

◆ unsubscribe() [1/2]

◆ n_subscriptions() [1/2]

◆ list_subscribers() [1/4]

◆ list_subscribers() [2/4]

◆ serialize() [1/2]

◆ check_no_subscribers()

◆ set_steps()

◆ set_variable()

◆ set_symmetric()

◆ set_transpose()

◆ set_debug()

◆ subscribe() [2/2]

◆ unsubscribe() [2/2]

◆ n_subscriptions() [2/2]

◆ list_subscribers() [3/4]

◆ list_subscribers() [4/4]

◆ serialize() [2/2]

Member Data Documentation

◆ minlevel

◆ objects

◆ counter

◆ counter_map

◆ validity_pointers

◆ object_info

◆ mutex

◆ vector_memory

◆ steps

◆ variable

◆ symmetric

◆ transpose

◆ debug