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

Inheritance diagram for MGSmootherRelaxation< MATRIX, RELAX, VECTOR >:
Inheritance graph
[legend]

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 MGMATRIXOBJECT , class DATA >
void initialize (const MGMATRIXOBJECT &matrices, const DATA &additional_data)
template<class MGMATRIXOBJECT , class DATA >
void initialize (const MGMATRIXOBJECT &matrices, const DATA &additional_data, const unsigned int block_row, const unsigned int block_col)
void clear ()
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)
virtual void smooth (const unsigned int level, VECTOR &u, const VECTOR &rhs) const
unsigned int memory_consumption () const

Public Attributes

MGLevelObject< RELAX > smoothers

Private Attributes

MGLevelObject< PointerMatrix
< MATRIX, VECTOR > > 
matrices
unsigned int steps
bool variable
bool symmetric
bool transpose
unsigned int debug
VectorMemory< VECTOR > & mem

Detailed Description

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

Smoother using relaxation classes.

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 Tvmult instead of the regular vmult 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.

Author:
Guido Kanschat, 2003

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 MGMATRIXOBJECT , class DATA >
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::initialize ( const MGMATRIXOBJECT &  matrices,
const DATA &  additional_data 
) [inline]

Initialize for matrices. The parameter matrices can be any object having functions get_minlevel() and get_maxlevel() as well as an operator[] returning a reference to MATRIX. This function stores pointers to the level matrices and initializes the smoothing operator 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 MGMATRIXOBJECT , class DATA >
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::initialize ( const MGMATRIXOBJECT &  matrices,
const DATA &  additional_data,
const unsigned int  block_row,
const unsigned int  block_col 
) [inline]

Initialize for single blocks of matrices. The parameter matrices can be any object having functions get_minlevel() and get_maxlevel() as well as an operator[] returning a reference to a block matrix where each block is of type MATRIX. 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 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>
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::set_steps ( const unsigned  int  ) 

Modify the number of smoothing steps on finest level.

template<class MATRIX, class RELAX, class VECTOR>
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::set_variable ( const   bool  ) 

Switch on/off variable smoothing.

template<class MATRIX, class RELAX, class VECTOR>
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::set_symmetric ( const   bool  ) 

Switch on/off symmetric smoothing.

template<class MATRIX, class RELAX, class VECTOR>
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::set_transpose ( const   bool  ) 

Switch on/off transposed smoothing. The effect is overriden by set_symmetric().

template<class MATRIX, class RELAX, class VECTOR>
void MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::set_debug ( const unsigned int  level  ) 

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

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>
unsigned int 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.

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

Pointer to the matrices.

template<class MATRIX, class RELAX, class VECTOR>
unsigned int MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::steps [private]

Number of smoothing steps on the finest level. If no variable smoothing is chosen, this is the number of steps on all levels.

template<class MATRIX, class RELAX, class VECTOR>
bool MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::variable [private]

Variable smoothing: double the number of smoothing steps whenever going to the next coarser level

template<class MATRIX, class RELAX, class VECTOR>
bool MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::symmetric [private]

Symmetric smoothing: in the smoothing iteration, alternate between the relaxation method and its transpose.

template<class MATRIX, class RELAX, class VECTOR>
bool MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::transpose [private]
template<class MATRIX, class RELAX, class VECTOR>
unsigned int MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::debug [private]

Output debugging information to deallog if this is nonzero.

template<class MATRIX, class RELAX, class VECTOR>
VectorMemory<VECTOR>& MGSmootherRelaxation< MATRIX, RELAX, VECTOR >::mem [private]

Memory for auxiliary vectors.


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

deal.II documentation generated on Mon Nov 23 22:57:57 2009 by doxygen 1.6.1