Reference documentation for deal.II version Git 74ec1a6c4b 2021-01-19 10:11:04 -0500
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Public Member Functions | Static Public Member Functions | Protected Attributes | List of all members
mg::SmootherRelaxation< RelaxationType, VectorType > Class Template Reference

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

Inheritance diagram for mg::SmootherRelaxation< RelaxationType, VectorType >:
[legend]

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 () override
 
virtual void smooth (const unsigned int level, VectorType &u, const VectorType &rhs) const override
 
virtual void apply (const unsigned int level, VectorType &u, const VectorType &rhs) const override
 
std::size_t memory_consumption () const
 
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, Args &&... args)
 
void clear_elements ()
 
unsigned int min_level () const
 
unsigned int max_level () const
 
void apply (ActionFunctionObjectType action)
 
template<class Archive >
void serialize (Archive &ar, const unsigned int version)
 
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)
 
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
 
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)
 
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<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.

Definition at line 183 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 ( )
overridevirtual

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
overridevirtual

The actual smoothing method.

Implements MGSmootherBase< VectorType >.

◆ apply() [1/2]

template<class RelaxationType, typename VectorType>
virtual void mg::SmootherRelaxation< RelaxationType, VectorType >::apply ( const unsigned int  level,
VectorType u,
const VectorType rhs 
) const
overridevirtual

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.

◆ operator[]() [1/2]

RelaxationType & MGLevelObject< RelaxationType >::operator[] ( const unsigned int  level)
inherited

Access object on level level.

Definition at line 206 of file mg_level_object.h.

◆ operator[]() [2/2]

const RelaxationType & MGLevelObject< RelaxationType >::operator[] ( const unsigned int  level) const
inherited

Access object on level level.

This function can be called on a const object, and consequently returns a const reference.

Definition at line 215 of file mg_level_object.h.

◆ resize()

void MGLevelObject< RelaxationType >::resize ( const unsigned int  new_minlevel,
const unsigned int  new_maxlevel,
Args &&...  args 
)
inherited

Delete all previous contents of this object and reset its size according to the values of new_minlevel and new_maxlevel.

Parameters
[in]new_minlevelThe lowest level for which to provision memory for level objects.
[in]new_maxlevelThe highest level for which to provision memory for level objects.
[in]argsOptional arguments passed to the constructor of the underlying object.
Precondition
minlevel <= maxlevel

Definition at line 226 of file mg_level_object.h.

◆ clear_elements()

void MGLevelObject< RelaxationType >::clear_elements ( )
inherited

Call clear on all objects stored by this object. This function is only implemented for some Object classes, e.g., matrix types or the PreconditionBlockSOR and similar classes. Using this function will fail with a compiler error if the Object template type to this class does not provide a clear() member function.

Definition at line 256 of file mg_level_object.h.

◆ min_level()

unsigned int MGLevelObject< RelaxationType >::min_level ( ) const
inherited

The coarsest level for which this class stores a level object.

Definition at line 266 of file mg_level_object.h.

◆ max_level()

unsigned int MGLevelObject< RelaxationType >::max_level ( ) const
inherited

The highest level for which this class stores a level object.

Definition at line 274 of file mg_level_object.h.

◆ apply() [2/2]

void MGLevelObject< RelaxationType >::apply ( ActionFunctionObjectType  action)
inherited

Apply the action action to every object stored in here. The parameter action is expected to be a function object that accepts the syntax action(const unsigned int level, Object &object); This means this function can accept a lambda, a std::function, or a plain function pointer.

Definition at line 282 of file mg_level_object.h.

◆ subscribe() [1/2]

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() [1/2]

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() [1/2]

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() [1/4]

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() [2/4]

void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

◆ serialize() [1/2]

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.

◆ set_steps()

template<typename VectorType>
void MGSmoother< VectorType >::set_steps ( const unsigned  int)
inherited

Modify the number of smoothing steps on finest level.

◆ set_variable()

template<typename VectorType>
void MGSmoother< VectorType >::set_variable ( const bool  )
inherited

Switch on/off variable smoothing.

◆ set_symmetric()

template<typename VectorType>
void MGSmoother< VectorType >::set_symmetric ( const bool  )
inherited

Switch on/off symmetric smoothing.

◆ set_transpose()

template<typename VectorType>
void MGSmoother< VectorType >::set_transpose ( const bool  )
inherited

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)
inherited

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

◆ subscribe() [2/2]

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() [2/2]

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() [2/2]

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() [3/4]

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() [4/4]

void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

◆ serialize() [2/2]

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
mutableprotectedinherited

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
protectedinherited

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
protectedinherited

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
protectedinherited

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
protectedinherited

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
protectedinherited

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: