Reference documentation for deal.II version 9.1.1
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Public Member Functions | 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
 
- Public Member Functions inherited from MGLevelObject< RelaxationType >
 MGLevelObject (const unsigned int minlevel=0, const unsigned int maxlevel=0)
 
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)
 
MGLevelObject< RelaxationType > & operator= (const double d)
 
void clear ()
 
void clear_elements ()
 
unsigned int min_level () const
 
unsigned int max_level () const
 
void apply (ActionFunctionObjectType action)
 
std::size_t memory_consumption () const
 
- Public Member Functions inherited from Subscriptor
 Subscriptor ()
 
 Subscriptor (const Subscriptor &)
 
 Subscriptor (Subscriptor &&) noexcept
 
virtual ~Subscriptor ()
 
Subscriptoroperator= (const Subscriptor &)
 
Subscriptoroperator= (Subscriptor &&) noexcept
 
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)
 
- Public Member Functions inherited from MGSmoother< VectorType >
 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)
 
- Public Member Functions inherited from MGSmootherBase< VectorType >
virtual ~MGSmootherBase () override=default
 

Additional Inherited Members

- Static Public Member Functions inherited from Subscriptor
static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)
 
- Protected Attributes inherited from MGSmoother< VectorType >
GrowingVectorMemory< VectorType > vector_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.

Author
Guido Kanschat,
Date
2003, 2009, 2010

Definition at line 190 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()

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.


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