Reference documentation for deal.II version Git 4a360c6 2017-05-26 05:30:59 +0200
Public Member Functions | Private Attributes | List of all members
DiagonalMatrix< VectorType > Class Template Reference

#include <deal.II/lac/diagonal_matrix.h>

Inheritance diagram for DiagonalMatrix< VectorType >:
[legend]

Public Member Functions

 DiagonalMatrix ()=default
 
void reinit (const VectorType &vec)
 
void compress (VectorOperation::values operation)
 
VectorType & get_vector ()
 
void clear ()
 
const VectorType & get_vector () const
 
size_type m () const
 
size_type n () const
 
value_type operator() (const size_type i, const size_type j) const
 
value_type & operator() (const size_type i, const size_type j)
 
template<typename number2 >
void add (const size_type row, const size_type n_cols, const size_type *col_indices, const number2 *values, const bool elide_zero_values=true, const bool col_indices_are_sorted=false)
 
void add (const size_type i, const size_type j, const value_type value)
 
void vmult (VectorType &dst, const VectorType &src) const
 
void Tvmult (VectorType &dst, const VectorType &src) const
 
void vmult_add (VectorType &dst, const VectorType &src) const
 
void Tvmult_add (VectorType &dst, const VectorType &src) const
 
std::size_t memory_consumption () const
 
- Public Member Functions inherited from Subscriptor
 Subscriptor ()
 
 Subscriptor (const Subscriptor &)
 
 Subscriptor (Subscriptor &&)
 
virtual ~Subscriptor ()
 
Subscriptoroperator= (const Subscriptor &)
 
Subscriptoroperator= (Subscriptor &&)
 
void subscribe (const char *identifier=nullptr) const
 
void unsubscribe (const char *identifier=nullptr) const
 
unsigned int n_subscriptions () const
 
void list_subscribers () const
 
template<class Archive >
void serialize (Archive &ar, const unsigned int version)
 

Private Attributes

VectorType diagonal
 

Additional Inherited Members

- Static Public Member Functions inherited from Subscriptor
static::ExceptionBase & ExcInUse (int arg1, char *arg2, std::string &arg3)
 
static::ExceptionBase & ExcNoSubscriber (char *arg1, char *arg2)
 

Detailed Description

template<typename VectorType = Vector<double>>
class DiagonalMatrix< VectorType >

This class represents a n x n diagonal matrix based on a vector of size n. The matrix-vector products are realized by VectorType::scale, so the template vector class needs to provide a scale() method.

When using this class with ConstraintsMatrix::distribute_local_to_global(), the underlying vector needs to provide write access to all entries referenced by cells in an assembly process. This means that this class also needs access to ghost entries that are owned by other processors than the calling one. In practice this requires initialization of the vector as follows

LinearAlgebra::distributed::Vector<double> &diagonal_vector = diagonal_matrix.get_vector();
diagonal_vector.reinit(locally_owned_dofs,
locally_relevant_dofs,
mpi_communicator);
Author
Martin Kronbichler, 2016

Definition at line 46 of file diagonal_matrix.h.

Constructor & Destructor Documentation

template<typename VectorType = Vector<double>>
DiagonalMatrix< VectorType >::DiagonalMatrix ( )
default

Constructor.

Member Function Documentation

template<typename VectorType = Vector<double>>
void DiagonalMatrix< VectorType >::reinit ( const VectorType &  vec)

Initialize with a given vector by copying the content of the vector vec.

template<typename VectorType = Vector<double>>
void DiagonalMatrix< VectorType >::compress ( VectorOperation::values  operation)

Compresses the data structures and allows the resulting matrix to be used in all other operations like matrix-vector products. This is a collective operation, i.e., it needs to be run on all processors when used in parallel.

template<typename VectorType = Vector<double>>
VectorType& DiagonalMatrix< VectorType >::get_vector ( )

Returns a reference to the underlying vector for manipulation of the entries on the matrix diagonal.

template<typename VectorType = Vector<double>>
void DiagonalMatrix< VectorType >::clear ( )

Clear content of this object and reset to the state of default constructor.

template<typename VectorType = Vector<double>>
const VectorType& DiagonalMatrix< VectorType >::get_vector ( ) const

Returns a read-only reference to the underlying vector.

template<typename VectorType = Vector<double>>
size_type DiagonalMatrix< VectorType >::m ( ) const

Number of rows of this matrix. This number corresponds to the size of the underlying vector.

template<typename VectorType = Vector<double>>
size_type DiagonalMatrix< VectorType >::n ( ) const

Number of columns of this matrix. This number corresponds to the size of the underlying vector.

template<typename VectorType = Vector<double>>
value_type DiagonalMatrix< VectorType >::operator() ( const size_type  i,
const size_type  j 
) const

Read-only access to a value. This is restricted to the case where i==j due to the matrix storage.

If the vector representing the diagonal is distributed with MPI, not all of the indices i might actually be accessible. Refer to the method get_vector().locally_owned_elements() for the entries that actually are accessible.

template<typename VectorType = Vector<double>>
value_type& DiagonalMatrix< VectorType >::operator() ( const size_type  i,
const size_type  j 
)

Read-write access to a value. This is restricted to the case where i==j due to the matrix storage.

If the vector representing the diagonal is distributed with MPI, not all of the indices i might actually be accessible. Refer to the method get_vector().locally_owned_elements() for the entries that actually are accessible.

template<typename VectorType = Vector<double>>
template<typename number2 >
void DiagonalMatrix< VectorType >::add ( const size_type  row,
const size_type  n_cols,
const size_type *  col_indices,
const number2 *  values,
const bool  elide_zero_values = true,
const bool  col_indices_are_sorted = false 
)

Add an array of values given by values in the given global matrix row at columns specified by col_indices. Due to the storage of this matrix, entries are only added to the diagonal of the matrix. All other entries are ignored and no exception is thrown.

This function is for a consistent interface with the other matrix classes in deal.II and can be used in ConstraintMatrix::distribute_local_to_global to get exactly the same diagonal as when assembling into a sparse matrix.

template<typename VectorType = Vector<double>>
void DiagonalMatrix< VectorType >::add ( const size_type  i,
const size_type  j,
const value_type  value 
)

Add value to the element (i,j).

Due to the storage of this matrix, entries are only added to the diagonal of the matrix. All other entries are ignored and no exception is thrown.

template<typename VectorType = Vector<double>>
void DiagonalMatrix< VectorType >::vmult ( VectorType &  dst,
const VectorType &  src 
) const

Performs a matrix-vector multiplication with the given matrix.

template<typename VectorType = Vector<double>>
void DiagonalMatrix< VectorType >::Tvmult ( VectorType &  dst,
const VectorType &  src 
) const

Performs a transpose matrix-vector multiplication with the given matrix. Since this represents a diagonal matrix, exactly the same as vmult().

template<typename VectorType = Vector<double>>
void DiagonalMatrix< VectorType >::vmult_add ( VectorType &  dst,
const VectorType &  src 
) const

Adds the result of a matrix-vector multiplication into the destination vector dst. Needs to create a temporary vector, which makes performance slower than for vmult().

template<typename VectorType = Vector<double>>
void DiagonalMatrix< VectorType >::Tvmult_add ( VectorType &  dst,
const VectorType &  src 
) const

Adds the result of a transpose matrix-vector multiplication into the destination vector dst. Needs to create a temporary vector, which makes performance slower than for Tvmult().

template<typename VectorType = Vector<double>>
std::size_t DiagonalMatrix< VectorType >::memory_consumption ( ) const

Return the memory consumption of this object.

Member Data Documentation

template<typename VectorType = Vector<double>>
VectorType DiagonalMatrix< VectorType >::diagonal
private

The stored vector.

Definition at line 190 of file diagonal_matrix.h.


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