Reference documentation for deal.II version Git d9a89af 2014-11-21 00:46:28 +0100
BlockIndices Class Reference

Auxiliary class aiding in the handling of block structures like in BlockVector or FESystem. More...

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

Inheritance diagram for BlockIndices:
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## Public Types

typedef types::global_dof_index size_type

## Public Member Functions

BlockIndices ()

BlockIndices (const std::vector< size_type > &n)

BlockIndices (const unsigned int n_blocks, const size_type block_size=0)

void reinit (const unsigned int n_blocks, const size_type n_elements_per_block)

void reinit (const std::vector< size_type > &n)

void push_back (const size_type size)

BlockIndicesoperator= (const BlockIndices &b)

bool operator== (const BlockIndices &b) const

void swap (BlockIndices &b)

std::size_t memory_consumption () const

Size information
unsigned int size () const

size_type total_size () const

size_type block_size (const unsigned int i) const

Index conversion

Functions in this group assume an object, which was created after sorting by block, such that each block forms a set of consecutive indices in the object. If applied to other objects, the numbers obtained from these functions are meaningless.

std::pair< unsigned int,
size_type
global_to_local (const size_type i) const

size_type local_to_global (const unsigned int block, const size_type index) const

size_type block_start (const unsigned int i) const

Public Member Functions inherited from Subscriptor
Subscriptor ()

Subscriptor (const Subscriptor &)

virtual ~Subscriptor ()

Subscriptoroperator= (const Subscriptor &)

void subscribe (const char *identifier=0) const

void unsubscribe (const char *identifier=0) const

unsigned int n_subscriptions () const

void list_subscribers () const

DeclException3 (ExcInUse, int, char *, std::string &,<< "Object of class "<< arg2<< " is still used by "<< arg1<< " other objects.\n"<< "(Additional information: "<< arg3<< ")\n"<< "Note the entry in the Frequently Asked Questions of "<< "deal.II (linked to from http://www.dealii.org/) for "<< "more information on what this error means.")

DeclException2 (ExcNoSubscriber, char *, char *,<< "No subscriber with identifier \""<< arg2<< "\" did subscribe to this object of class "<< arg1)

template<class Archive >
void serialize (Archive &ar, const unsigned int version)

## Private Attributes

unsigned int n_blocks

std::vector< size_typestart_indices

## Related Functions

(Note that these are not member functions.)

void swap (BlockIndices &u, BlockIndices &v)

## Detailed Description

Auxiliary class aiding in the handling of block structures like in BlockVector or FESystem.

The information obtained from this class falls into two groups. First, it is possible to obtain the number of blocks, namely size(), the block_size() for each block and the total_size() of the object described by the block indices, namely the length of the whole index set. These functions do not make any assumption on the ordering of the index set.

If on the other hand the index set is ordered "by blocks", such that each block forms a consecutive set of indices, this class that manages the conversion of global indices into a block vector or matrix to the local indices within this block. This is required, for example, when you address a global element in a block vector and want to know which element within which block this is. It is also useful if a matrix is composed of several blocks, where you have to translate global row and column indices to local ones.

Block (linear algebra)

Definition at line 54 of file block_indices.h.

## Member Typedef Documentation

Declare the type for container size.

Definition at line 60 of file block_indices.h.

## Constructor & Destructor Documentation

 BlockIndices::BlockIndices ( )
inline

Default constructor. Initialize for zero blocks.

Definition at line 367 of file block_indices.h.

 BlockIndices::BlockIndices ( const std::vector< size_type > & n )
inline

Constructor. Initialize the number of entries in each block i as n[i]. The number of blocks will be the size of the vector

Definition at line 390 of file block_indices.h.

 BlockIndices::BlockIndices ( const unsigned int n_blocks, const size_type block_size = 0 )
inlineexplicit

Specialized constructor for a structure with blocks of equal size.

Definition at line 376 of file block_indices.h.

## Member Function Documentation

 void BlockIndices::reinit ( const unsigned int n_blocks, const size_type n_elements_per_block )
inline

Reinitialize the number of blocks and assign each block the same number of elements.

Definition at line 340 of file block_indices.h.

 void BlockIndices::reinit ( const std::vector< size_type > & n )
inline

Reinitialize the number of indices within each block from the given argument. The number of blocks will be adjusted to the size of n and the size of block i is set to n[i].

Definition at line 353 of file block_indices.h.

 void BlockIndices::push_back ( const size_type size )
inline

Add another block of given size to the end of the block structure.

Definition at line 401 of file block_indices.h.

 unsigned int BlockIndices::size ( ) const
inline

Number of blocks in index field.

Definition at line 440 of file block_indices.h.

 BlockIndices::size_type BlockIndices::total_size ( ) const
inline

Return the total number of indices accumulated over all blocks, that is, the dimension of the vector space of the block vector.

Definition at line 449 of file block_indices.h.

 BlockIndices::size_type BlockIndices::block_size ( const unsigned int i ) const
inline

The size of the ith block.

Definition at line 459 of file block_indices.h.

 std::pair< unsigned int, BlockIndices::size_type > BlockIndices::global_to_local ( const size_type i ) const
inline

Return the block and the index within that block for the global index i. The first element of the pair is the block, the second the index within it.

Definition at line 411 of file block_indices.h.

 BlockIndices::size_type BlockIndices::local_to_global ( const unsigned int block, const size_type index ) const
inline

Return the global index of index in block block.

Definition at line 427 of file block_indices.h.

 BlockIndices::size_type BlockIndices::block_start ( const unsigned int i ) const
inline

The start index of the ith block.

Definition at line 469 of file block_indices.h.

 BlockIndices & BlockIndices::operator= ( const BlockIndices & b )
inline

Copy operator.

Definition at line 479 of file block_indices.h.

 bool BlockIndices::operator== ( const BlockIndices & b ) const
inline

Compare whether two objects are the same, i.e. whether the number of blocks and the sizes of all blocks are equal.

Definition at line 490 of file block_indices.h.

 void BlockIndices::swap ( BlockIndices & b )
inline

Swap the contents of these two objects.

Definition at line 506 of file block_indices.h.

 std::size_t BlockIndices::memory_consumption ( ) const
inline

Determine an estimate for the memory consumption (in bytes) of this object.

Definition at line 519 of file block_indices.h.

## Friends And Related Function Documentation

 void swap ( BlockIndices & u, BlockIndices & v )
related

Global function swap which overloads the default implementation of the C++ standard library which uses a temporary object. The function simply exchanges the data of the two objects.

Definition at line 539 of file block_indices.h.

## Member Data Documentation

 unsigned int BlockIndices::n_blocks
private

Number of blocks. While this value could be obtained through start_indices.size()-1, we cache this value for faster access.

Definition at line 210 of file block_indices.h.

 std::vector BlockIndices::start_indices
private

Global starting index of each vector. The last and redundant value is the total number of entries.

Definition at line 218 of file block_indices.h.

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