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

Inheritance diagram for MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >:

Public Member Functions
	MGSmootherPrecondition (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 PreconditionerType::AdditionalData &additional_data=typename PreconditionerType::AdditionalData())

template<typename MatrixType2 >
void	initialize_matrices (const MGLevelObject< MatrixType2 > &matrices)

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

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

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

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

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)

Public Attributes
MGLevelObject< PreconditionerType >	smoothers

Protected Attributes
GrowingVectorMemory< VectorType >	vector_memory

unsigned int	steps

bool	variable

bool	symmetric

bool	transpose

unsigned int	debug

Private Attributes
MGLevelObject< LinearOperator< VectorType > >	matrices

Subscriptor functionality
Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.
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

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

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

using	map_value_type = decltype(counter_map)::value_type

using	map_iterator = decltype(counter_map)::iterator

static std::mutex	mutex

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

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

void	check_no_subscribers () const noexcept

Detailed Description

template<typename MatrixType, typename PreconditionerType, typename VectorType>
class MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >

Smoother using preconditioner classes.

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 Tvmult instead of the regular vmult 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.

The library contains instantiation for SparseMatrix<.> and Vector<.>, where the template arguments are all combinations of float and double. Additional instantiations may be created by including the file mg_smoother.templates.h.

Definition at line 444 of file mg_smoother.h.

Constructor & Destructor Documentation

◆ MGSmootherPrecondition()

template<typename MatrixType , typename PreconditionerType , typename VectorType >

MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::MGSmootherPrecondition	(	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() [1/4]

template<typename MatrixType , typename PreconditionerType , typename VectorType >

template<typename MatrixType2 >

void MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::initialize	(	const MGLevelObject< MatrixType2 > &	matrices,
		const typename PreconditionerType::AdditionalData &	additional_data = `typename PreconditionerType::AdditionalData()`
	)

Initialize for matrices. This function stores pointers to the level matrices and initializes the smoothing operator with the same smoother for each level.

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

◆ initialize_matrices()

template<typename MatrixType , typename PreconditionerType , typename VectorType >

template<typename MatrixType2 >

void MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::initialize_matrices ( const MGLevelObject< MatrixType2 > & matrices )

In contrast to the function above, only initialize the matrices. The smoothers need to be set up manually by the user as a subsequent step in the code. For this purpose, the public field smoothers can be directly modified. This is useful if one wants full flexibility in the choice of smoothers, e.g., use different smoothers on the levels.

◆ initialize() [2/4]

template<typename MatrixType , typename PreconditionerType , typename VectorType >

template<typename MatrixType2 , class DATA >

void MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::initialize	(	const MGLevelObject< MatrixType2 > &	matrices,
		const MGLevelObject< DATA > &	additional_data
	)

Initialize for matrices. This function stores pointers to the level matrices and initializes the smoothing operator with the according smoother for each level.

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

◆ initialize() [3/4]

template<typename MatrixType , typename PreconditionerType , typename VectorType >

template<typename MatrixType2 , class DATA >

void MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::initialize	(	const MGLevelObject< MatrixType2 > &	matrices,
		const DATA &	additional_data,
		const unsigned int	block_row,
		const unsigned int	block_col
	)

Initialize for single blocks of matrices. Of this block matrix, the block indicated by block_row and block_col is selected on each level. This function stores pointers to the level matrices and initializes the smoothing operator with the same smoother for each level.

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

◆ initialize() [4/4]

template<typename MatrixType , typename PreconditionerType , typename VectorType >

template<typename MatrixType2 , class DATA >

void MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::initialize	(	const MGLevelObject< MatrixType2 > &	matrices,
		const MGLevelObject< DATA > &	additional_data,
		const unsigned int	block_row,
		const unsigned int	block_col
	)

Initialize for single blocks of matrices. Of this block matrix, the block indicated by block_row and block_col is selected on each level. This function stores pointers to the level matrices and initializes the smoothing operator with the according smoother for each level.

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

◆ clear()

template<typename MatrixType , typename PreconditionerType , typename VectorType >

void MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::clear ( )

overridevirtual

Empty all vectors.

Implements MGSmootherBase< VectorType >.

◆ smooth()

template<typename MatrixType , typename PreconditionerType , typename VectorType >

virtual void MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::smooth	(	const unsigned int	level,
		VectorType &	u,
		const VectorType &	rhs
	)		const

overridevirtual

The actual smoothing method.

Implements MGSmootherBase< VectorType >.

◆ apply()

template<typename MatrixType , typename PreconditionerType , typename VectorType >

virtual void MGSmootherPrecondition< MatrixType, PreconditionerType, 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);

MGSmootherPrecondition::smooth

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

level

unsigned int level

Definition: grid_out.cc:4606

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<typename MatrixType , typename PreconditionerType , typename VectorType >

std::size_t MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::memory_consumption ( ) const

Memory used by this object.

◆ 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

Member Data Documentation

◆ smoothers

template<typename MatrixType , typename PreconditionerType , typename VectorType >

MGLevelObject<PreconditionerType> MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::smoothers

Object containing relaxation methods.

Definition at line 566 of file mg_smoother.h.

◆ matrices

template<typename MatrixType , typename PreconditionerType , typename VectorType >

MGLevelObject<LinearOperator<VectorType> > MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >::matrices

private

Pointer to the matrices.

Definition at line 579 of file mg_smoother.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 98 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 104 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 110 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 116 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 122 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 127 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

Public Attributes

Protected Attributes

Private Attributes

Subscriptor functionality

Detailed Description

Constructor & Destructor Documentation

◆ MGSmootherPrecondition()

Member Function Documentation

◆ initialize() [1/4]

◆ initialize_matrices()

◆ initialize() [2/4]

◆ initialize() [3/4]

◆ initialize() [4/4]

◆ clear()

◆ smooth()

◆ apply()

◆ memory_consumption()

◆ set_steps()

◆ set_variable()

◆ set_symmetric()

◆ set_transpose()

◆ set_debug()

Member Data Documentation

◆ smoothers

◆ matrices

◆ vector_memory

◆ steps

◆ variable

◆ symmetric

◆ transpose

◆ debug