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Reference documentation for deal.II version Git 292c2606a1 2021-03-03 00:48:14 +0100
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#include <deal.II/multigrid/mg_base.h>
Public Member Functions | |
virtual | ~MGSmootherBase () override=default |
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 ::ExceptionBase & | ExcInUse (int arg1, std::string arg2, std::string arg3) |
static ::ExceptionBase & | ExcNoSubscriber (std::string arg1, std::string arg2) |
Base class for multigrid smoothers. Does nothing but defining the interface used by multigrid methods.
The smoother interface provides two methods, a smooth() method and an apply() method. The multigrid preconditioner interfaces distinguish between the two for efficiency reasons: Upon entry to the preconditioner operations, the vector u
needs to be set to zero and smoothing starts by a simple application of the smoother on the rhs
vector. This method is provided by the apply() method of this class. It is the same as first setting u
to zero and then calling smooth(), but for many classes the separate apply() interface is more efficient because it can skip one matrix-vector product.
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().
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overridevirtualdefault |
Virtual destructor.
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pure virtual |
Release matrices.
Implemented in MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >, MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >, mg::SmootherRelaxation< RelaxationType, VectorType >, MGSmootherIdentity< VectorType >, and MGSmootherBlock< MatrixType, RelaxationType, number >.
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pure virtual |
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 MGSmootherPrecondition< MatrixType, PreconditionerType, VectorType >, MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >, mg::SmootherRelaxation< RelaxationType, VectorType >, MGSmootherIdentity< VectorType >, and MGSmootherBlock< MatrixType, RelaxationType, number >.
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virtual |
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
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.
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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.
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inherited |
Unsubscribes a user from the object.
identifier
and the validity
pointer must be the same as the one supplied to subscribe(). Definition at line 156 of file subscriptor.cc.
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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.
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inlineinherited |
List the subscribers to the input stream
.
Definition at line 318 of file subscriptor.h.
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inherited |
List the subscribers to deallog
.
Definition at line 204 of file subscriptor.cc.
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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.