Reference documentation for deal.II version GIT b206511199 2023-01-31 13:40:02+00:00

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

Inheritance diagram for BlockIndices:
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## 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)

BlockIndicesoperator= (const BlockIndices &b)

BlockIndicesoperator= (BlockIndices &&) noexcept

bool operator== (const BlockIndices &b) const

void swap (BlockIndices &b)

std::size_t memory_consumption () const

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

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

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_typeglobal_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

Subscriptor functionality

Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.

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

## Static Public Member Functions

static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)

## Private Types

using map_value_type = decltype(counter_map)::value_type

using map_iterator = decltype(counter_map)::iterator

## Private Member Functions

void check_no_subscribers () const noexcept

## Private Attributes

unsigned int n_blocks

std::vector< size_typestart_indices

std::atomic< unsigned int > counter

std::map< std::string, unsigned int > counter_map

std::vector< std::atomic< bool > * > validity_pointers

const std::type_info * object_info

## Static Private Attributes

static std::mutex mutex

## Related Functions

(Note that these are not member functions.)

void swap (BlockIndices &u, BlockIndices &v)

## 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.

Block (linear algebra)

Definition at line 60 of file block_indices.h.

## ◆ size_type

Declare the type for container size.

Definition at line 66 of file block_indices.h.

## ◆ map_value_type

 using Subscriptor::map_value_type = decltype(counter_map)::value_type
privateinherited

The data type used in counter_map.

Definition at line 230 of file subscriptor.h.

## ◆ map_iterator

 using Subscriptor::map_iterator = decltype(counter_map)::iterator
privateinherited

The iterator type used in counter_map.

Definition at line 235 of file subscriptor.h.

## ◆ BlockIndices() [1/5]

 BlockIndices::BlockIndices ( )
inline

Default constructor. Initialize for zero blocks.

Definition at line 282 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 300 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 309 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 289 of file block_indices.h.

## ◆ 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 258 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 269 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 320 of file block_indices.h.

## ◆ size()

 unsigned int BlockIndices::size ( ) const
inline

Number of blocks in index field.

Definition at line 354 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 362 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 372 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 381 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 329 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 343 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 397 of file block_indices.h.

## ◆ operator=() [1/2]

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

Copy operator.

Definition at line 406 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 416 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 430 of file block_indices.h.

## ◆ swap()

 void BlockIndices::swap ( BlockIndices & b )
inline

Swap the contents of these two objects.

Definition at line 445 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 454 of file block_indices.h.

## ◆ subscribe()

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

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 136 of file subscriptor.cc.

## ◆ unsubscribe()

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

Unsubscribes a user from the object.

Note
The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 156 of file subscriptor.cc.

## ◆ n_subscriptions()

 unsigned int Subscriptor::n_subscriptions ( ) const
inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

## ◆ list_subscribers() [1/2]

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

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

## ◆ list_subscribers() [2/2]

 void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

## ◆ serialize()

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

Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 309 of file subscriptor.h.

## ◆ check_no_subscribers()

 void Subscriptor::check_no_subscribers ( ) const
privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note
Since this function is just a consistency check it does nothing in release mode.
If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 53 of file subscriptor.cc.

## ◆ swap()

 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 472 of file block_indices.h.

## ◆ 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 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.

## ◆ counter

 std::atomic Subscriptor::counter
mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 219 of file subscriptor.h.

## ◆ counter_map

 std::map Subscriptor::counter_map
mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 225 of file subscriptor.h.

## ◆ validity_pointers

 std::vector *> Subscriptor::validity_pointers
mutableprivateinherited

In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.

Definition at line 241 of file subscriptor.h.

## ◆ object_info

 const std::type_info* Subscriptor::object_info
mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 249 of file subscriptor.h.

## ◆ mutex

 std::mutex Subscriptor::mutex
staticprivateinherited

A mutex used to ensure data consistency when printing out the list of subscribers.

Definition at line 271 of file subscriptor.h.

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