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

Inheritance diagram for BlockSparsityPattern:

[legend]

Public Types
using	size_type = types::global_dof_index

Public Member Functions
	BlockSparsityPattern ()=default

	BlockSparsityPattern (const size_type n_rows, const size_type n_columns)

void	reinit (const size_type n_block_rows, const size_type n_block_columns)

void	reinit (const BlockIndices &row_indices, const BlockIndices &col_indices, const std::vector< std::vector< unsigned int > > &row_lengths)

bool	is_compressed () const

void	copy_from (const BlockDynamicSparsityPattern &dsp)

void	collect_sizes ()

SparsityPattern &	block (const size_type row, const size_type column)

const SparsityPattern &	block (const size_type row, const size_type column) const

const BlockIndices &	get_row_indices () const

const BlockIndices &	get_column_indices () const

void	compress ()

size_type	n_block_rows () const

size_type	n_block_cols () const

bool	empty () const

size_type	max_entries_per_row () const

void	add (const size_type i, const size_type j)

void	add_entries (const size_type row, ForwardIterator begin, ForwardIterator end, const bool indices_are_sorted=false)

virtual void	add_entries (const ArrayView< const std::pair< size_type, size_type > > &entries)

virtual void	add_row_entries (const size_type &row, const ArrayView< const size_type > &columns, const bool indices_are_sorted=false) override

bool	exists (const size_type i, const size_type j) const

unsigned int	row_length (const size_type row) const

size_type	n_nonzero_elements () const

void	print (std::ostream &out) const

void	print_gnuplot (std::ostream &out) const

void	print_svg (std::ostream &out) const

std::size_t	memory_consumption () const

size_type	n_rows () const

size_type	n_cols () const

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

EnableObserverPointer functionality
Classes derived from EnableObserverPointer provide a facility to subscribe to this object. This is mostly used by the ObserverPointer 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 ::ExceptionBase &	ExcNeedsCollectSizes ()

static ::ExceptionBase &	ExcIncompatibleRowNumbers (int arg1, int arg2, int arg3, int arg4)

static ::ExceptionBase &	ExcIncompatibleColNumbers (int arg1, int arg2, int arg3, int arg4)

static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

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

Static Public Attributes
static const size_type	invalid_entry

Protected Member Functions
virtual void	resize (const size_type rows, const size_type cols)

Protected Attributes
size_type	block_rows

size_type	block_columns

Table< 2, std::unique_ptr< SparsityPattern > >	sub_objects

BlockIndices	row_indices

BlockIndices	column_indices

size_type	rows

size_type	cols

Private Types
using	map_value_type = decltype(counter_map)::value_type

using	map_iterator = decltype(counter_map)::iterator

Private Member Functions
size_type	compute_n_rows () const

size_type	compute_n_cols () const

void	check_no_subscribers () const noexcept

Private Attributes
std::vector< size_type >	counter_within_block

std::vector< std::vector< size_type > >	block_column_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

Detailed Description

This class extends the base class to implement an array of sparsity patterns that can be used by block sparse matrix objects. It only adds a few additional member functions, but the main interface stems from the base class, see there for more information.

This class is an example of the "static" type of Sparsity patterns.

Definition at line 436 of file block_sparsity_pattern.h.

Member Typedef Documentation

◆ size_type

using BlockSparsityPatternBase< SparsityPattern >::size_type = types::global_dof_index

inherited

Declare type for container size.

Definition at line 85 of file block_sparsity_pattern.h.

◆ map_value_type

using EnableObserverPointer::map_value_type = decltype(counter_map)::value_type

privateinherited

The data type used in counter_map.

Definition at line 238 of file enable_observer_pointer.h.

◆ map_iterator

using EnableObserverPointer::map_iterator = decltype(counter_map)::iterator

privateinherited

The iterator type used in counter_map.

Definition at line 243 of file enable_observer_pointer.h.

Constructor & Destructor Documentation

◆ BlockSparsityPattern() [1/2]

BlockSparsityPattern::BlockSparsityPattern ( )

default

Initialize the matrix empty, that is with no memory allocated. This is useful if you want such objects as member variables in other classes. You can make the structure usable by calling the reinit() function.

◆ BlockSparsityPattern() [2/2]

BlockSparsityPattern::BlockSparsityPattern	(	const size_type	n_rows,
		const size_type	n_columns
	)

Initialize the matrix with the given number of block rows and columns. The blocks themselves are still empty, and you have to call collect_sizes() after you assign them sizes.

Definition at line 367 of file block_sparsity_pattern.cc.

Member Function Documentation

◆ reinit() [1/2]

void BlockSparsityPattern::reinit	(	const size_type	n_block_rows,
		const size_type	n_block_columns
	)

inline

Forwarding to BlockSparsityPatternBase::reinit().

Definition at line 1079 of file block_sparsity_pattern.h.

◆ reinit() [2/2]

void BlockSparsityPattern::reinit	(	const BlockIndices &	row_indices,
		const BlockIndices &	col_indices,
		const std::vector< std::vector< unsigned int > > &	row_lengths
	)

Initialize the pattern with two BlockIndices for the block structures of matrix rows and columns as well as a row length vector.

The row length vector should be in the format produced by DoFTools. Alternatively, there is a simplified version, where each of the inner vectors has length one. Then, the corresponding entry is used as the maximal row length.

For the diagonal blocks, the inner SparsityPattern is initialized with optimized diagonals, while this is not done for the off-diagonal blocks.

Definition at line 374 of file block_sparsity_pattern.cc.

◆ is_compressed()

bool BlockSparsityPattern::is_compressed ( ) const

Return whether the structure is compressed or not, i.e. whether all sub-matrices are compressed.

Definition at line 412 of file block_sparsity_pattern.cc.

◆ copy_from()

void BlockSparsityPattern::copy_from ( const BlockDynamicSparsityPattern & dsp )

Copy data from an object of type BlockDynamicSparsityPattern, i.e. resize this object to the size of the given argument, and copy over the contents of each of the subobjects. Previous content of this object is lost.

Definition at line 424 of file block_sparsity_pattern.cc.

◆ collect_sizes()

void BlockSparsityPatternBase< SparsityPattern >::collect_sizes ( )

inherited

This function collects the sizes of the sub-objects and stores them in internal arrays, in order to be able to relay global indices into the matrix to indices into the subobjects. You must call this function each time after you have changed the size of the sub-objects.

Definition at line 151 of file block_sparsity_pattern.cc.

◆ block() [1/2]

SparsityPattern & BlockSparsityPatternBase< SparsityPattern >::block	(	const size_type	row,
		const size_type	column
	)

inlineinherited

Access the block with the given coordinates.

Definition at line 157 of file block_sparsity_pattern.h.

◆ block() [2/2]

const SparsityPattern & BlockSparsityPatternBase< SparsityPattern >::block	(	const size_type	row,
		const size_type	column
	)		const

inlineinherited

Access the block with the given coordinates. Version for constant objects.

Definition at line 164 of file block_sparsity_pattern.h.

◆ get_row_indices()

const BlockIndices & BlockSparsityPatternBase< SparsityPattern >::get_row_indices ( ) const

inlineinherited

Grant access to the object describing the distribution of row indices to the individual blocks.

Definition at line 171 of file block_sparsity_pattern.h.

◆ get_column_indices()

const BlockIndices & BlockSparsityPatternBase< SparsityPattern >::get_column_indices ( ) const

inlineinherited

Grant access to the object describing the distribution of column indices to the individual blocks.

Definition at line 178 of file block_sparsity_pattern.h.

◆ compress()

void BlockSparsityPatternBase< SparsityPattern >::compress ( )

inherited

This function compresses the sparsity structures that this object represents. It simply calls compress for all sub-objects.

Definition at line 185 of file block_sparsity_pattern.cc.

◆ n_block_rows()

BlockSparsityPatternBase< SparsityPattern >::size_type BlockSparsityPatternBase< SparsityPattern >::n_block_rows ( ) const

inlineinherited

Return the number of blocks in a column.

Definition at line 191 of file block_sparsity_pattern.h.

◆ n_block_cols()

BlockSparsityPatternBase< SparsityPattern >::size_type BlockSparsityPatternBase< SparsityPattern >::n_block_cols ( ) const

inlineinherited

Return the number of blocks in a row.

Definition at line 197 of file block_sparsity_pattern.h.

◆ empty()

bool BlockSparsityPatternBase< SparsityPattern >::empty ( ) const

inherited

Return whether the object is empty. It is empty if no memory is allocated, which is the same as that both dimensions are zero. This function is just the concatenation of the respective call to all sub-matrices.

Definition at line 206 of file block_sparsity_pattern.cc.

◆ max_entries_per_row()

BlockSparsityPatternBase< SparsityPattern >::size_type BlockSparsityPatternBase< SparsityPattern >::max_entries_per_row ( ) const

inherited

Return the maximum number of entries per row. It returns the maximal number of entries per row accumulated over all blocks in a row, and the maximum over all rows.

Definition at line 214 of file block_sparsity_pattern.cc.

◆ add()

void BlockSparsityPatternBase< SparsityPattern >::add	(	const size_type	i,
		const size_type	j
	)

inlineinherited

Add a nonzero entry to the matrix. This function may only be called for non-compressed sparsity patterns.

If the entry already exists, nothing bad happens.

This function simply finds out to which block (i,j) belongs and then relays to that block.

Definition at line 226 of file block_sparsity_pattern.h.

◆ add_entries() [1/2]

void BlockSparsityPatternBase< SparsityPattern >::add_entries	(	const size_type	row,
		ForwardIterator	begin,
		ForwardIterator	end,
		const bool	indices_are_sorted = `false`
	)

inherited

Add several nonzero entries to the specified matrix row. This function may only be called for non-compressed sparsity patterns.

If some of the entries already exist, nothing bad happens.

This function simply finds out to which blocks (row,col) for col in the iterator range belong and then relays to those blocks.

Definition at line 240 of file block_sparsity_pattern.h.

◆ add_entries() [2/2]

void SparsityPatternBase::add_entries ( const ArrayView< const std::pair< size_type, size_type > > & entries )

virtualinherited

General function for adding new entries from an unsorted list of pairs.

This function is useful when multiple entries need to be added which do not correspond to a particular row, e.g., when assembling a flux sparsity pattern.

Reimplemented from SparsityPatternBase.

Definition at line 255 of file sparsity_pattern_base.cc.

◆ add_row_entries()

void BlockSparsityPatternBase< SparsityPattern >::add_row_entries	(	const size_type &	row,
		const ArrayView< const size_type > &	columns,
		const bool	indices_are_sorted = `false`
	)

overridevirtualinherited

Add several nonzero entries to the specified matrix row. This function may only be called for non-compressed sparsity patterns and works the same way as the overload which takes iterators.

Implements SparsityPatternBase.

Definition at line 251 of file block_sparsity_pattern.h.

◆ exists()

bool BlockSparsityPatternBase< SparsityPattern >::exists	(	const size_type	i,
		const size_type	j
	)		const

inlineinherited

Check if a value at a certain position may be non-zero.

Definition at line 274 of file block_sparsity_pattern.h.

◆ row_length()

unsigned int BlockSparsityPatternBase< SparsityPattern >::row_length ( const size_type row ) const

inlineinherited

Number of entries in a specific row, added up over all the blocks that form this row.

Definition at line 281 of file block_sparsity_pattern.h.

◆ n_nonzero_elements()

BlockSparsityPatternBase< SparsityPattern >::size_type BlockSparsityPatternBase< SparsityPattern >::n_nonzero_elements ( ) const

inherited

Return the number of nonzero elements of this matrix. Actually, it returns the number of entries in the sparsity pattern; if any of the entries should happen to be zero, it is counted anyway.

This function may only be called if the matrix struct is compressed. It does not make too much sense otherwise anyway.

In the present context, it is the sum of the values as returned by the sub-objects.

Definition at line 295 of file block_sparsity_pattern.cc.

◆ print()

void BlockSparsityPatternBase< SparsityPattern >::print ( std::ostream & out ) const

inherited

Print the sparsity of the matrix. The output consists of one line per row of the format [i,j1,j2,j3,...]. i is the row number and jn are the allocated columns in this row.

Definition at line 303 of file block_sparsity_pattern.cc.

◆ print_gnuplot()

void BlockSparsityPatternBase< SparsityPattern >::print_gnuplot ( std::ostream & out ) const

inherited

Print the sparsity of the matrix in a format that gnuplot understands and which can be used to plot the sparsity pattern in a graphical way. This is the same functionality implemented for usual sparsity patterns, see SparsityPattern::print_gnuplot().

Definition at line 313 of file block_sparsity_pattern.cc.

◆ print_svg()

void BlockSparsityPatternBase< SparsityPattern >::print_svg ( std::ostream & out ) const

inherited

Print the sparsity of the matrix in svg format. This is the same functionality implemented for usual sparsity patterns, see SparsityPattern::print_svg().

Definition at line 321 of file block_sparsity_pattern.cc.

◆ memory_consumption()

std::size_t BlockSparsityPatternBase< SparsityPattern >::memory_consumption ( ) const

inherited

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

Definition at line 328 of file block_sparsity_pattern.cc.

◆ ExcNeedsCollectSizes()

static ::ExceptionBase & BlockSparsityPatternBase< SparsityPattern >::ExcNeedsCollectSizes ( )

staticinherited

Exception

Note: The message that will be printed by this exception reads:
"The number of rows and columns (returned by n_rows() and n_cols()) does " "not match their directly computed values. This typically means that a " "call to collect_sizes() is missing."

◆ ExcIncompatibleRowNumbers()

static ::ExceptionBase & BlockSparsityPatternBase< SparsityPattern >::ExcIncompatibleRowNumbers	(	int	arg1,
		int	arg2,
		int	arg3,
		int	arg4
	)

staticinherited

Exception

Note: The message that will be printed by this exception reads:
<< "The blocks [" << arg1 << ',' << arg2 << "] and [" << arg3 << ',' << arg4 << "] have differing row numbers."

◆ ExcIncompatibleColNumbers()

static ::ExceptionBase & BlockSparsityPatternBase< SparsityPattern >::ExcIncompatibleColNumbers	(	int	arg1,
		int	arg2,
		int	arg3,
		int	arg4
	)

staticinherited

Exception

Note: The message that will be printed by this exception reads:
<< "The blocks [" << arg1 << ',' << arg2 << "] and [" << arg3 << ',' << arg4 << "] have differing column numbers."

◆ compute_n_rows()

BlockSparsityPatternBase< SparsityPattern >::size_type BlockSparsityPatternBase< SparsityPattern >::compute_n_rows ( ) const

privateinherited

Internal utility function for computing the number of rows.

Definition at line 399 of file block_sparsity_pattern.cc.

◆ compute_n_cols()

BlockSparsityPatternBase< SparsityPattern >::size_type BlockSparsityPatternBase< SparsityPattern >::compute_n_cols ( ) const

privateinherited

Internal utility function for computing the number of columns.

Definition at line 405 of file block_sparsity_pattern.cc.

◆ n_rows()

size_type SparsityPatternBase::n_rows ( ) const

inherited

Return number of rows of this matrix, which equals the dimension of the image space. It is the sum of rows of the (block-)rows of sub-matrices.

◆ n_cols()

size_type SparsityPatternBase::n_cols ( ) const

inherited

Return number of columns of this matrix, which equals the dimension of the range space. It is the sum of columns of the (block-)columns of sub-matrices.

◆ resize()

virtual void SparsityPatternBase::resize	(	const size_type	rows,
		const size_type	cols
	)

protectedvirtualinherited

Internal function for updating the stored size of the sparsity pattern.

◆ subscribe()

void EnableObserverPointer::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 131 of file enable_observer_pointer.cc.

◆ unsubscribe()

void EnableObserverPointer::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 151 of file enable_observer_pointer.cc.

◆ n_subscriptions()

unsigned int EnableObserverPointer::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 322 of file enable_observer_pointer.h.

◆ list_subscribers() [1/2]

template<typename StreamType >

void EnableObserverPointer::list_subscribers ( StreamType & stream ) const

inlineinherited

List the subscribers to the input stream.

Definition at line 339 of file enable_observer_pointer.h.

◆ list_subscribers() [2/2]

void EnableObserverPointer::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 199 of file enable_observer_pointer.cc.

◆ serialize()

template<class Archive >

void EnableObserverPointer::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 331 of file enable_observer_pointer.h.

◆ check_no_subscribers()

void EnableObserverPointer::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 enable_observer_pointer.cc.

Member Data Documentation

◆ invalid_entry

const size_type BlockSparsityPatternBase< SparsityPattern >::invalid_entry

staticinherited

Define a value which is used to indicate that a certain value in the colnums array is unused, i.e. does not represent a certain column number index.

This value is only an alias to the respective value of the SparsityPattern class.

Definition at line 95 of file block_sparsity_pattern.h.

◆ block_rows

size_type BlockSparsityPatternBase< SparsityPattern >::block_rows

protectedinherited

Number of block rows.

Definition at line 370 of file block_sparsity_pattern.h.

◆ block_columns

size_type BlockSparsityPatternBase< SparsityPattern >::block_columns

protectedinherited

Number of block columns.

Definition at line 375 of file block_sparsity_pattern.h.

◆ sub_objects

Table<2, std::unique_ptr<SparsityPattern > > BlockSparsityPatternBase< SparsityPattern >::sub_objects

protectedinherited

Array of sparsity patterns.

Definition at line 380 of file block_sparsity_pattern.h.

◆ row_indices

BlockIndices BlockSparsityPatternBase< SparsityPattern >::row_indices

protectedinherited

Object storing and managing the transformation of row indices to indices of the sub-objects.

Definition at line 386 of file block_sparsity_pattern.h.

◆ column_indices

BlockIndices BlockSparsityPatternBase< SparsityPattern >::column_indices

protectedinherited

Object storing and managing the transformation of column indices to indices of the sub-objects.

Definition at line 392 of file block_sparsity_pattern.h.

◆ counter_within_block

std::vector<size_type> BlockSparsityPatternBase< SparsityPattern >::counter_within_block

privateinherited

Temporary vector for counting the elements written into the individual blocks when doing a collective add or set.

Definition at line 411 of file block_sparsity_pattern.h.

◆ block_column_indices

std::vector<std::vector<size_type> > BlockSparsityPatternBase< SparsityPattern >::block_column_indices

privateinherited

Temporary vector for column indices on each block when writing local to global data on each sparse matrix.

Definition at line 417 of file block_sparsity_pattern.h.

◆ rows

size_type SparsityPatternBase::rows

protectedinherited

Number of rows that this sparsity pattern shall represent.

Definition at line 121 of file sparsity_pattern_base.h.

◆ cols

size_type SparsityPatternBase::cols

protectedinherited

Number of columns that this sparsity pattern shall represent.

Definition at line 126 of file sparsity_pattern_base.h.

◆ counter

std::atomic<unsigned int> EnableObserverPointer::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 227 of file enable_observer_pointer.h.

◆ counter_map

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

mutableprivateinherited

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

Definition at line 233 of file enable_observer_pointer.h.

◆ validity_pointers

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

mutableprivateinherited

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

Definition at line 249 of file enable_observer_pointer.h.

◆ object_info

const std::type_info* EnableObserverPointer::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 257 of file enable_observer_pointer.h.

◆ mutex

std::mutex EnableObserverPointer::mutex

staticprivateinherited

A mutex used to ensure data consistency when accessing the mutable members of this class. This lock is used in the subscribe() and unsubscribe() functions, as well as in list_subscribers().

Definition at line 280 of file enable_observer_pointer.h.

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

include/deal.II/lac/block_sparsity_pattern.h
source/lac/block_sparsity_pattern.cc

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Member Typedef Documentation

◆ size_type

◆ map_value_type

◆ map_iterator

Constructor & Destructor Documentation

◆ BlockSparsityPattern() [1/2]

◆ BlockSparsityPattern() [2/2]

Member Function Documentation

◆ reinit() [1/2]

◆ reinit() [2/2]

◆ is_compressed()

◆ copy_from()

◆ collect_sizes()

◆ block() [1/2]

◆ block() [2/2]

◆ get_row_indices()

◆ get_column_indices()

◆ compress()

◆ n_block_rows()

◆ n_block_cols()

◆ empty()

◆ max_entries_per_row()

◆ add()

◆ add_entries() [1/2]

◆ add_entries() [2/2]

◆ add_row_entries()

◆ exists()

◆ row_length()

◆ n_nonzero_elements()

◆ print()

◆ print_gnuplot()

◆ print_svg()

◆ memory_consumption()

◆ ExcNeedsCollectSizes()

◆ ExcIncompatibleRowNumbers()

◆ ExcIncompatibleColNumbers()

◆ compute_n_rows()

◆ compute_n_cols()

◆ n_rows()

◆ n_cols()

◆ resize()

◆ subscribe()

◆ unsubscribe()

◆ n_subscriptions()

◆ list_subscribers() [1/2]

◆ list_subscribers() [2/2]

◆ serialize()

◆ check_no_subscribers()

Member Data Documentation

◆ invalid_entry

◆ block_rows

◆ block_columns

◆ sub_objects

◆ row_indices

◆ column_indices

◆ counter_within_block

◆ block_column_indices

◆ rows

◆ cols

◆ counter

◆ counter_map

◆ validity_pointers

◆ object_info

◆ mutex