Reference documentation for deal.II version Git c9feb145b3 2021-03-01 21:22:52 +0100
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Public Member Functions | Static Public Member Functions | Protected Attributes | List of all members
MGSmoother< VectorType > Class Template Referenceabstract

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

Inheritance diagram for MGSmoother< VectorType >:
[legend]

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
 
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
 

Static Public Member Functions

static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)
 

Protected Attributes

GrowingVectorMemory< VectorTypevector_memory
 
unsigned int steps
 
bool variable
 
bool symmetric
 
bool transpose
 
unsigned int debug
 

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

◆ smooth()

template<typename VectorType>
virtual void MGSmootherBase< VectorType >::smooth ( const unsigned int  level,
VectorType u,
const VectorType rhs 
) const
pure virtualinherited

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

Definition at line 35 of file mg_base.cc.

◆ subscribe()

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()

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()

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 301 of file subscriptor.h.

◆ list_subscribers() [1/2]

template<typename StreamType >
void Subscriptor::list_subscribers ( StreamType &  stream) const
inlineinherited

List the subscribers to the input stream.

Definition at line 318 of file subscriptor.h.

◆ list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

◆ serialize()

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 310 of file subscriptor.h.

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.


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