Public Member Functions | Public Attributes | Private Attributes

MGSmootherRelaxation< MATRIX, RELAX, VECTOR > Class Template Reference
[Multilevel support]

Inheritance diagram for MGSmootherRelaxation< MATRIX, RELAX, VECTOR >:
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List of all members.

Public Member Functions

 MGSmootherRelaxation (VectorMemory< VECTOR > &mem, const unsigned int steps=1, const bool variable=false, const bool symmetric=false, const bool transpose=false)
template<class MATRIX2 >
void initialize (const MGLevelObject< MATRIX2 > &matrices, const typename RELAX::AdditionalData &additional_data=typename RELAX::AdditionalData())
template<class MATRIX2 , class DATA >
void initialize (const MGLevelObject< MATRIX2 > &matrices, const MGLevelObject< DATA > &additional_data)
template<class MATRIX2 , class DATA >
void initialize (const MGLevelObject< MATRIX2 > &matrices, const DATA &additional_data, const unsigned int block_row, const unsigned int block_col)
template<class MATRIX2 , class DATA >
void initialize (const MGLevelObject< MATRIX2 > &matrices, const MGLevelObject< DATA > &additional_data, const unsigned int block_row, const unsigned int block_col)
void clear ()
virtual void smooth (const unsigned int level, VECTOR &u, const VECTOR &rhs) const
std::size_t memory_consumption () const

Public Attributes

MGLevelObject< RELAX > smoothers

Private Attributes

MGLevelObject< PointerMatrix
< MATRIX, VECTOR > > 
matrices

Detailed Description

template<class MATRIX, class RELAX, class VECTOR>
class MGSmootherRelaxation< MATRIX, RELAX, VECTOR >

Smoother using relaxation classes.

A relaxation class is an object that has two member functions,

 void  step(VECTOR& x, const VECTOR& d) const;
 void Tstep(VECTOR& x, const VECTOR& d) const;

performing one step of the smoothing scheme.

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.

The library contains instantiation for SparseMatrix<.> and Vector<.>, where the template arguments are all combinations of float and double. Additional instantiations may be created by including the file mg_smoother.templates.h.

Note:
If '--enable-mgcompatibility' was used on configuring deal.II, this class behaves like MGSmootherPrecondition.
Author:
Guido Kanschat, 2003

Definition at line 356 of file mg_smoother.h.


Constructor & Destructor Documentation

template<class MATRIX, class RELAX, class VECTOR>
MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::MGSmootherRelaxation ( VectorMemory< VECTOR > &  mem,
const unsigned int  steps = 1,
const bool  variable = false,
const bool  symmetric = false,
const bool  transpose = false 
)

Constructor. Sets memory and smoothing parameters.


Member Function Documentation

template<class MATRIX, class RELAX, class VECTOR>
template<class MATRIX2 >
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::initialize ( const MGLevelObject< MATRIX2 > &  matrices,
const typename RELAX::AdditionalData &  additional_data = typename RELAX::AdditionalData() 
)

Initialize for matrices. This function stores pointers to the level matrices and initializes the smoothing operator with the same smoother for each level.

additional_data is an object of type RELAX::AdditionalData and is handed to the initialization function of the relaxation method.

template<class MATRIX, class RELAX, class VECTOR>
template<class MATRIX2 , class DATA >
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::initialize ( const MGLevelObject< MATRIX2 > &  matrices,
const MGLevelObject< DATA > &  additional_data 
)

Initialize for matrices. This function stores pointers to the level matrices and initializes the smoothing operator with the according smoother for each level.

additional_data is an object of type RELAX::AdditionalData and is handed to the initialization function of the relaxation method.

template<class MATRIX, class RELAX, class VECTOR>
template<class MATRIX2 , class DATA >
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::initialize ( const MGLevelObject< MATRIX2 > &  matrices,
const DATA &  additional_data,
const unsigned int  block_row,
const unsigned int  block_col 
)

Initialize for single blocks of matrices. Of this block matrix, the block indicated by block_row and block_col is selected on each level. This function stores pointers to the level matrices and initializes the smoothing operator with the same smoother for each level.

additional_data is an object of type RELAX::AdditionalData and is handed to the initialization function of the relaxation method.

template<class MATRIX, class RELAX, class VECTOR>
template<class MATRIX2 , class DATA >
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::initialize ( const MGLevelObject< MATRIX2 > &  matrices,
const MGLevelObject< DATA > &  additional_data,
const unsigned int  block_row,
const unsigned int  block_col 
)

Initialize for single blocks of matrices. Of this block matrix, the block indicated by block_row and block_col is selected on each level. This function stores pointers to the level matrices and initializes the smoothing operator with the according smoother for each level.

additional_data is an object of type RELAX::AdditionalData and is handed to the initialization function of the relaxation method.

template<class MATRIX, class RELAX, class VECTOR>
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::clear (  ) [virtual]

Empty all vectors.

Implements MGSmootherBase< VECTOR >.

template<class MATRIX, class RELAX, class VECTOR>
virtual void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::smooth ( const unsigned int  level,
VECTOR &  u,
const VECTOR &  rhs 
) const [virtual]

The actual smoothing method.

Implements MGSmootherBase< VECTOR >.

template<class MATRIX, class RELAX, class VECTOR>
std::size_t MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::memory_consumption (  ) const

Memory used by this object.


Member Data Documentation

template<class MATRIX, class RELAX, class VECTOR>
MGLevelObject<RELAX> MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::smoothers

Object containing relaxation methods.

Definition at line 475 of file mg_smoother.h.

template<class MATRIX, class RELAX, class VECTOR>
MGLevelObject<PointerMatrix<MATRIX, VECTOR> > MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::matrices [private]

Pointer to the matrices.

Definition at line 487 of file mg_smoother.h.


The documentation for this class was generated from the following file:
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deal.II documentation generated on Fri Feb 3 2012 06:04:09 by doxygen 1.7.2