#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 ()

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

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

std::size_t	memory_consumption () const

Public Member Functions inherited from MGLevelObject< RelaxationType >
	MGLevelObject (const unsigned int minlevel=0, const unsigned int maxlevel=0)

RelaxationType &	operator[] (const unsigned int level)

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

void	resize (const unsigned int new_minlevel, const unsigned int new_maxlevel)

MGLevelObject< RelaxationType > &	operator= (const double d)

void	clear ()

void	clear_elements ()

unsigned int	min_level () const

unsigned int	max_level () const

void	apply (ActionFunctionObjectType action)

std::size_t	memory_consumption () const

Public Member Functions inherited from Subscriptor
	Subscriptor ()

	Subscriptor (const Subscriptor &)

	Subscriptor (Subscriptor &&) noexcept

virtual	~Subscriptor ()

Subscriptor &	operator= (const Subscriptor &)

Subscriptor &	operator= (Subscriptor &&) noexcept

void	subscribe (const char *identifier=nullptr) const

void	unsubscribe (const char *identifier=nullptr) const

unsigned int	n_subscriptions () const

void	list_subscribers () const

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

Public Member Functions inherited from MGSmoother< VectorType >
	MGSmoother (const unsigned int steps=1, const bool variable=false, const bool symmetric=false, const bool transpose=false)

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 Member Functions inherited from MGSmootherBase< VectorType >
virtual	~MGSmootherBase ()=default

Additional Inherited Members
Static Public Member Functions inherited from Subscriptor
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

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

Protected Attributes inherited from MGSmoother< VectorType >
GrowingVectorMemory< VectorType >	vector_memory

unsigned int	steps

bool	variable

bool	symmetric

bool	transpose

unsigned int	debug

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.

Author: Guido Kanschat,

Date: 2003, 2009, 2010

Definition at line 181 of file mg_smoother.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 ( )

virtual

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

virtual

The actual smoothing method.

Implements MGSmootherBase< VectorType >.

◆ apply()

template<class RelaxationType, typename VectorType>

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

virtual

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);

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.

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

deal.II/multigrid/mg_smoother.h

Public Member Functions

Additional Inherited Members

Detailed Description

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

Constructor & Destructor Documentation

◆ SmootherRelaxation()

Member Function Documentation

◆ initialize() [1/2]

◆ initialize() [2/2]

◆ clear()

◆ smooth()

◆ apply()

◆ memory_consumption()

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