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

Inheritance diagram for BlockIndices:

Public Types
using	size_type = types::global_dof_index

Public Member Functions
	BlockIndices ()

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

	BlockIndices (BlockIndices &&b) noexcept

	BlockIndices (const BlockIndices &)=default

	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 > &block_sizes)

void	push_back (const size_type size)

Size information
unsigned int	size () const

size_type	total_size () const

size_type	block_size (const unsigned int i) const

std::string	to_string () const

Public Member Functions inherited from Subscriptor
	Subscriptor ()

	Subscriptor (const Subscriptor &)

	Subscriptor (Subscriptor &&) noexcept

virtual	~Subscriptor ()

Subscriptor &	operator= (const Subscriptor &)

Subscriptor &	operator= (Subscriptor &&) noexcept

void	subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

void	unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

unsigned int	n_subscriptions () const

template<typename StreamType >
void	list_subscribers (StreamType &stream) const

void	list_subscribers () const

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

Related Functions
(Note that these are not member functions.)
void	swap (BlockIndices &u, BlockIndices &v)

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.
unsigned int	n_blocks

std::vector< size_type >	start_indices

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

BlockIndices &	operator= (const BlockIndices &b)

BlockIndices &	operator= (BlockIndices &&) noexcept

bool	operator== (const BlockIndices &b) const

void	swap (BlockIndices &b)

std::size_t	memory_consumption () const

Additional Inherited Members
Static Public Member Functions inherited from Subscriptor
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Detailed Description

BlockIndices represents a range of indices (such as the range \([0,N)\) of valid indices for elements of a vector) and how this one range is broken down into smaller but contiguous "blocks" (such as the velocity and pressure parts of a solution vector). In particular, it provides the ability to translate between global indices and the indices within a block. This class is used, for example, in the BlockVector, BlockSparsityPattern, and BlockMatrixBase classes.

The information that can be obtained from this class falls into two groups. First, it is possible to query the global size of the index space (through the total_size() member function), and the number of blocks and their sizes (via size() and the block_size() functions).

Secondly, this class manages the conversion of global indices to the local indices within this block, and the other way around. This is required, for example, when you address a global element in a block vector and want to know within which block this is, and which index within this block it corresponds to. 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 60 of file block_indices.h.

Member Typedef Documentation

◆ size_type

using BlockIndices::size_type = types::global_dof_index

Declare the type for container size.

Definition at line 66 of file block_indices.h.

Constructor & Destructor Documentation

◆ BlockIndices() [1/5]

BlockIndices::BlockIndices ( )

inline

Default constructor. Initialize for zero blocks.

Definition at line 284 of file block_indices.h.

◆ BlockIndices() [2/5]

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

inline

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

Definition at line 302 of file block_indices.h.

◆ BlockIndices() [3/5]

BlockIndices::BlockIndices ( BlockIndices && b )

inlinenoexcept

Move constructor. Initialize a new object by stealing the internal data of another BlockIndices object.

Definition at line 311 of file block_indices.h.

◆ BlockIndices() [4/5]

BlockIndices::BlockIndices ( const BlockIndices & )

default

Copy constructor.

◆ BlockIndices() [5/5]

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 291 of file block_indices.h.

Member Function Documentation

◆ reinit() [1/2]

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 260 of file block_indices.h.

◆ reinit() [2/2]

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

inline

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

Definition at line 271 of file block_indices.h.

◆ push_back()

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 322 of file block_indices.h.

◆ size()

unsigned int BlockIndices::size ( ) const

inline

Number of blocks in index field.

Definition at line 356 of file block_indices.h.

◆ total_size()

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 364 of file block_indices.h.

◆ block_size()

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

inline

The size of the ith block.

Definition at line 374 of file block_indices.h.

◆ to_string()

std::string BlockIndices::to_string ( ) const

inline

String representation of the block sizes. The output is of the form [nb->b1,b2,b3|s], where nb is n_blocks(), s is total_size() and b1 etc. are the values returned by block_size() for each of the blocks.

Definition at line 383 of file block_indices.h.

◆ global_to_local()

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 331 of file block_indices.h.

◆ local_to_global()

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 345 of file block_indices.h.

◆ block_start()

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

inline

The start index of the ith block.

Definition at line 399 of file block_indices.h.

◆ operator=() [1/2]

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

inline

Copy operator.

Definition at line 408 of file block_indices.h.

◆ operator=() [2/2]

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

inlinenoexcept

Move assignment operator. Move another BlockIndices object onto the current one by transferring its contents.

Definition at line 418 of file block_indices.h.

◆ operator==()

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 432 of file block_indices.h.

◆ swap()

void BlockIndices::swap ( BlockIndices & b )

inline

Swap the contents of these two objects.

Definition at line 447 of file block_indices.h.

◆ memory_consumption()

std::size_t BlockIndices::memory_consumption ( ) const

inline

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

Definition at line 456 of file block_indices.h.

Friends And Related Function Documentation

◆ swap()

void swap	(	BlockIndices &	u,
		BlockIndices &	v
	)

Author: Wolfgang Bangerth, 2000

Definition at line 475 of file block_indices.h.

Member Data Documentation

◆ n_blocks

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 222 of file block_indices.h.

◆ start_indices

std::vector<size_type> BlockIndices::start_indices

private

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

Definition at line 228 of file block_indices.h.

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

include/deal.II/lac/block_indices.h

Public Types

Public Member Functions

Related Functions

Index conversion

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ size_type

Constructor & Destructor Documentation

◆ BlockIndices() [1/5]

◆ BlockIndices() [2/5]

◆ BlockIndices() [3/5]

◆ BlockIndices() [4/5]

◆ BlockIndices() [5/5]

Member Function Documentation

◆ reinit() [1/2]

◆ reinit() [2/2]

◆ push_back()

◆ size()

◆ total_size()

◆ block_size()

◆ to_string()

◆ global_to_local()

◆ local_to_global()

◆ block_start()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ operator==()

◆ swap()

◆ memory_consumption()

Friends And Related Function Documentation

◆ swap()

Member Data Documentation

◆ n_blocks

◆ start_indices