MGSmoother< VectorType > Class Template Reference

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

Inheritance diagram for MGSmoother< VectorType >:

Public Member Functions
	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)
virtual void	clear ()=0
virtual void	smooth (const unsigned int level, VectorType &u, const VectorType &rhs) const =0
virtual void	apply (const unsigned int level, VectorType &u, const VectorType &rhs) const

Protected Attributes
GrowingVectorMemory< VectorType >	vector_memory
unsigned int	steps
bool	variable
bool	symmetric
bool	transpose
unsigned int	debug

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
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
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 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 VectorType>
class MGSmoother< VectorType >

A base class for smoother handling information on smoothing. While not adding to the abstract interface in MGSmootherBase, this class stores information on the number and type of smoothing steps, which in turn can be used by a derived class.

Definition at line 48 of file mg_smoother.h.

Constructor & Destructor Documentation

MGSmoother()

template<typename VectorType >

MGSmoother< VectorType >::MGSmoother	(	const unsigned int	steps = 1,
		const bool	variable = false,
		const bool	symmetric = false,
		const bool	transpose = false
	)

Constructor.

Member Function Documentation

set_steps()

template<typename VectorType >

void MGSmoother< VectorType >::set_steps

(

const unsigned int

)

Modify the number of smoothing steps on finest level.

set_variable()

template<typename VectorType >

void MGSmoother< VectorType >::set_variable

(

const bool

)

Switch on/off variable smoothing.

set_symmetric()

template<typename VectorType >

void MGSmoother< VectorType >::set_symmetric

(

const bool

)

Switch on/off symmetric smoothing.

set_transpose()

template<typename VectorType >

void MGSmoother< VectorType >::set_transpose

(

const bool

)

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

)

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

clear()

template<typename VectorType >

virtual void MGSmootherBase< VectorType >::clear ( )

pure virtualinherited

Release matrices.

Implemented in MGSmootherBlock< MatrixType, RelaxationType, number >, MGSmootherIdentity< VectorType >, MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >, mg::SmootherRelaxation< RelaxationType, VectorType >, and MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >.

smooth()

template<typename VectorType >

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

pure virtualinherited

Smoothing function that smooths the content in u given the right hand side vector rhs. This is the function used in multigrid methods.

Implemented in MGSmootherIdentity< VectorType >, MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >, mg::SmootherRelaxation< RelaxationType, VectorType >, and MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >.

apply()

template<typename VectorType >

void MGSmootherBase< VectorType >::apply ( const unsigned int  level, VectorType &  u, const VectorType &  rhs  ) const

virtualinherited

As opposed to the smooth() function, this function applies the action of the smoothing, overwriting the previous content in the vector u. This function must be equivalent to the following code

u = 0;
smooth(level, u, rhs);

but can usually be implemented more efficiently than the former. If a particular smoother does not override the apply() method, the default implementation as described here is used.

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 in MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >, mg::SmootherRelaxation< RelaxationType, VectorType >, and MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >.

Definition at line 35 of file mg_base.cc.

Member Data Documentation

vector_memory

template<typename VectorType >

GrowingVectorMemory<VectorType> MGSmoother< VectorType >::vector_memory

mutableprotected

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

protected

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

protected

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

protected

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

protected

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

protected

Output debugging information to deallog if this is nonzero.

Definition at line 127 of file mg_smoother.h.

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

• include/deal.II/multigrid/mg_smoother.h