Public Member Functions | Private Attributes | Related Functions

BlockIndices Class Reference
[Data storage primitives]

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

Inheritance diagram for BlockIndices:
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List of all members.

Public Member Functions

 BlockIndices ()
 BlockIndices (const std::vector< unsigned int > &n)
 BlockIndices (const unsigned int n_blocks, const unsigned int block_size=0)
void reinit (const unsigned int n_blocks, const unsigned int n_elements_per_block)
void reinit (const std::vector< unsigned int > &n)
void push_back (const unsigned int 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
unsigned int total_size () const
unsigned int 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,
unsigned int > 
global_to_local (const unsigned int i) const
unsigned int local_to_global (const unsigned int block, const unsigned int index) const
unsigned int block_start (const unsigned int i) const

Private Attributes

unsigned int n_blocks
std::vector< unsigned int > start_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.

See also:
Block (linear algebra)
Author:
Wolfgang Bangerth, Guido Kanschat, 2000, 2007, 2011

Definition at line 49 of file block_indices.h.


Constructor & Destructor Documentation

BlockIndices::BlockIndices (  ) [inline]

Default constructor. Initialize for zero blocks.

Definition at line 352 of file block_indices.h.

BlockIndices::BlockIndices ( const std::vector< unsigned int > &  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 375 of file block_indices.h.

References reinit().

BlockIndices::BlockIndices ( const unsigned int  n_blocks,
const unsigned int  block_size = 0 
) [inline, explicit]

Specialized constructor for a structure with blocks of equal size.

Definition at line 361 of file block_indices.h.

References n_blocks, and start_indices.


Member Function Documentation

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

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

Definition at line 325 of file block_indices.h.

References n_blocks, and start_indices.

Referenced by BlockIndices(), TrilinosWrappers::BlockVector::operator=(), TrilinosWrappers::MPI::BlockVector::operator=(), PETScWrappers::MPI::BlockVector::reinit(), PETScWrappers::BlockVector::reinit(), and internal::reinit().

void BlockIndices::reinit ( const std::vector< unsigned int > &  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 338 of file block_indices.h.

References n_blocks, and start_indices.

void BlockIndices::push_back ( const unsigned int  size ) [inline]

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

Definition at line 386 of file block_indices.h.

References AssertDimension, n_blocks, and start_indices.

unsigned int BlockIndices::size (  ) const [inline]
unsigned int 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 432 of file block_indices.h.

References n_blocks, and start_indices.

Referenced by global_to_local(), operator<<(), and BlockInfo::print().

unsigned int BlockIndices::block_size ( const unsigned int  i ) const [inline]
std::pair< unsigned int, unsigned int > BlockIndices::global_to_local ( const unsigned int  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 396 of file block_indices.h.

References Assert, StandardExceptions::ExcIndexRange(), n_blocks, start_indices, and total_size().

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

Return the global index of index in block block.

Definition at line 410 of file block_indices.h.

References Assert, StandardExceptions::ExcIndexRange(), n_blocks, and start_indices.

unsigned int BlockIndices::block_start ( const unsigned int  i ) const [inline]
BlockIndices & BlockIndices::operator= ( const BlockIndices b ) [inline]

Copy operator.

Definition at line 462 of file block_indices.h.

References n_blocks, and start_indices.

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 473 of file block_indices.h.

References n_blocks, and start_indices.

void BlockIndices::swap ( BlockIndices b ) [inline]

Swap the contents of these two objects.

Definition at line 489 of file block_indices.h.

References Assert, StandardExceptions::ExcDimensionMismatch(), n_blocks, start_indices, and swap().

Referenced by swap().

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

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

Definition at line 502 of file block_indices.h.

References start_indices.


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.

Author:
Wolfgang Bangerth, 2000

Definition at line 522 of file block_indices.h.

References swap().


Member Data Documentation

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

Definition at line 201 of file block_indices.h.

Referenced by block_size(), block_start(), BlockIndices(), global_to_local(), local_to_global(), operator=(), operator==(), push_back(), reinit(), size(), swap(), and total_size().

std::vector<unsigned int> BlockIndices::start_indices [private]

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

Definition at line 209 of file block_indices.h.

Referenced by block_size(), block_start(), BlockIndices(), global_to_local(), local_to_global(), memory_consumption(), operator=(), operator==(), push_back(), reinit(), swap(), and total_size().


The documentation for this class was generated from the following file:
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deal.II documentation generated on Fri Feb 3 2012 06:04:05 by doxygen 1.7.2