Reference documentation for deal.II version Git ac854ef673 2021-03-06 10:09:45 +0100
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Public Member Functions | Static Public Member Functions | List of all members
MGSmootherIdentity< VectorType > Class Template Reference

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

Inheritance diagram for MGSmootherIdentity< VectorType >:

Public Member Functions

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

Detailed Description

template<typename VectorType>
class MGSmootherIdentity< VectorType >

Smoother doing nothing. This class is not useful for many applications other than for testing some multigrid procedures. Also some applications might get convergence without smoothing and then this class brings you the cheapest possible multigrid.

Definition at line 138 of file mg_smoother.h.

Member Function Documentation

◆ smooth()

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

Implementation of the interface for Multigrid. This function does nothing, which by comparison with the definition of this function means that the smoothing operator equals the null operator.

Implements MGSmootherBase< VectorType >.

◆ clear()

template<typename VectorType >
virtual void MGSmootherIdentity< VectorType >::clear ( )

Release matrices.

Implements MGSmootherBase< VectorType >.

◆ apply()

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

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

◆ subscribe()

void Subscriptor::subscribe ( std::atomic< bool > *const  validity,
const std::string &  identifier = "" 
) const

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

◆ unsubscribe()

void Subscriptor::unsubscribe ( std::atomic< bool > *const  validity,
const std::string &  identifier = "" 
) const

Unsubscribes a user from the object.

The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 156 of file

◆ n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const

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

List the subscribers to the input stream.

Definition at line 318 of file subscriptor.h.

◆ list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const

List the subscribers to deallog.

Definition at line 204 of file

◆ serialize()

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

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.

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