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

Inheritance diagram for DynamicSparsityPattern:

Classes
struct	Line

Public Types
using	size_type = types::global_dof_index

using	iterator = DynamicSparsityPatternIterators::Iterator

using	const_iterator = DynamicSparsityPatternIterators::Iterator

Public Member Functions
	DynamicSparsityPattern ()

	DynamicSparsityPattern (const DynamicSparsityPattern &)

	DynamicSparsityPattern (const size_type m, const size_type n, const IndexSet &rowset=IndexSet())

	DynamicSparsityPattern (const IndexSet &indexset)

	DynamicSparsityPattern (const size_type n)

DynamicSparsityPattern &	operator= (const DynamicSparsityPattern &)

void	reinit (const size_type m, const size_type n, const IndexSet &rowset=IndexSet())

void	compress ()

bool	empty () const

size_type	max_entries_per_row () const

void	add (const size_type i, const size_type j)

template<typename ForwardIterator >
void	add_entries (const size_type row, ForwardIterator begin, ForwardIterator end, const bool indices_are_unique_and_sorted=false)

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

void	symmetrize ()

template<typename SparsityPatternTypeLeft , typename SparsityPatternTypeRight >
void	compute_mmult_pattern (const SparsityPatternTypeLeft &left, const SparsityPatternTypeRight &right)

void	print (std::ostream &out) const

void	print_gnuplot (std::ostream &out) const

size_type	n_rows () const

size_type	n_cols () const

size_type	row_length (const size_type row) const

size_type	column_number (const size_type row, const size_type index) const

size_type	bandwidth () const

size_type	n_nonzero_elements () const

const IndexSet &	row_index_set () const

size_type	memory_consumption () const

Iterators
iterator	begin () const

iterator	end () const

iterator	begin (const size_type r) const

iterator	end (const size_type r) 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 (const char *identifier=nullptr) const

void	unsubscribe (const char *identifier=nullptr) 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)

Static Public Member Functions
static bool	stores_only_added_elements ()

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)

Private Attributes
bool	have_entries

size_type	rows

size_type	cols

IndexSet	rowset

std::vector< Line >	lines

Friends
class	DynamicSparsityPatternIterators::Accessor

Detailed Description

This class acts as an intermediate form of the SparsityPattern class. From the interface it mostly represents a SparsityPattern object that is kept compressed at all times. However, since the final sparsity pattern is not known while constructing it, keeping the pattern compressed at all times can only be achieved at the expense of either increased memory or run time consumption upon use. The main purpose of this class is to avoid some memory bottlenecks, so we chose to implement it memory conservative. The chosen data format is too unsuited to be used for actual matrices, though. It is therefore necessary to first copy the data of this object over to an object of type SparsityPattern before using it in actual matrices.

Another viewpoint is that this class does not need up front allocation of a certain amount of memory, but grows as necessary. An extensive description of sparsity patterns can be found in the documentation of the Sparsity patterns module.

This class is an example of the "dynamic" type of Sparsity patterns. It is used in most tutorial programs in one way or another.

Interface

Since this class is intended as an intermediate replacement of the SparsityPattern class, it has mostly the same interface, with small changes where necessary. In particular, the add() function, and the functions inquiring properties of the sparsity pattern are the same.

Usage

Use this class as follows:

DynamicSparsityPattern dynamic_pattern (dof_handler.n_dofs());
DoFTools::make_sparsity_pattern (dof_handler,
                                 dynamic_pattern);
constraints.condense (dynamic_pattern);
SparsityPattern sp;
sp.copy_from (dynamic_pattern);

Author: Timo Heister, 2008

Definition at line 303 of file dynamic_sparsity_pattern.h.

Member Typedef Documentation

using DynamicSparsityPattern::size_type = types::global_dof_index

Declare the type for container size.

Definition at line 309 of file dynamic_sparsity_pattern.h.

using DynamicSparsityPattern::iterator = DynamicSparsityPatternIterators::Iterator

Typedef an for iterator class that allows to walk over all nonzero elements of a sparsity pattern.

Since the iterator does not allow to modify the sparsity pattern, this type is the same as that for const_iterator.

Definition at line 318 of file dynamic_sparsity_pattern.h.

using DynamicSparsityPattern::const_iterator = DynamicSparsityPatternIterators::Iterator

Typedef for an iterator class that allows to walk over all nonzero elements of a sparsity pattern.

Definition at line 324 of file dynamic_sparsity_pattern.h.

Constructor & Destructor Documentation

DynamicSparsityPattern::DynamicSparsityPattern ( )

Initialize as an empty object. 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.

Definition at line 220 of file dynamic_sparsity_pattern.cc.

DynamicSparsityPattern::DynamicSparsityPattern ( const DynamicSparsityPattern & s )

Copy constructor. This constructor is only allowed to be called if the sparsity structure to be copied is empty. This is so in order to prevent involuntary copies of objects for temporaries, which can use large amounts of computing time. However, copy constructors are needed if you want to place a DynamicSparsityPattern in a container, e.g. to write such statements like v.push_back (DynamicSparsityPattern());, with v a vector of DynamicSparsityPattern objects.

Definition at line 229 of file dynamic_sparsity_pattern.cc.

DynamicSparsityPattern::DynamicSparsityPattern	(	const size_type	m,
		const size_type	n,
		const IndexSet &	rowset = `IndexSet()`
	)

Initialize a rectangular sparsity pattern with m rows and n columns. The rowset restricts the storage to elements in rows of this set. Adding elements outside of this set has no effect. The default argument keeps all entries.

Definition at line 246 of file dynamic_sparsity_pattern.cc.

DynamicSparsityPattern::DynamicSparsityPattern ( const IndexSet & indexset )

Create a square SparsityPattern using the given index set. The total size is given by the size of indexset and only rows corresponding to indices in indexset are stored on the current processor.

Definition at line 258 of file dynamic_sparsity_pattern.cc.

DynamicSparsityPattern::DynamicSparsityPattern ( const size_type n )

Initialize a square pattern of dimension n.

Definition at line 268 of file dynamic_sparsity_pattern.cc.

Member Function Documentation

DynamicSparsityPattern & DynamicSparsityPattern::operator= ( const DynamicSparsityPattern & s )

Copy operator. For this the same holds as for the copy constructor: it is declared, defined and fine to be called, but the latter only for empty objects.

Definition at line 280 of file dynamic_sparsity_pattern.cc.

void DynamicSparsityPattern::reinit	(	const size_type	m,
		const size_type	n,
		const IndexSet &	rowset = `IndexSet()`
	)

Reallocate memory and set up data structures for a new sparsity pattern with m rows and n columns. The rowset restricts the storage to elements in rows of this set. Adding elements outside of this set has no effect. The default argument keeps all entries.

Definition at line 299 of file dynamic_sparsity_pattern.cc.

void DynamicSparsityPattern::compress ( )

Since this object is kept compressed at all times anyway, this function does nothing, but is declared to make the interface of this class as much alike as that of the SparsityPattern class.

Definition at line 324 of file dynamic_sparsity_pattern.cc.

bool DynamicSparsityPattern::empty ( ) const

Return whether the object is empty. It is empty if no memory is allocated, which is the same as that both dimensions are zero.

Definition at line 330 of file dynamic_sparsity_pattern.cc.

DynamicSparsityPattern::size_type DynamicSparsityPattern::max_entries_per_row ( ) const

Return the maximum number of entries per row. Note that this number may change as entries are added.

Definition at line 338 of file dynamic_sparsity_pattern.cc.

void DynamicSparsityPattern::add	(	const size_type	i,
		const size_type	j
	)

inline

Add a nonzero entry. If the entry already exists, this call does nothing.

Definition at line 946 of file dynamic_sparsity_pattern.h.

template<typename ForwardIterator >

void DynamicSparsityPattern::add_entries	(	const size_type	row,
		ForwardIterator	begin,
		ForwardIterator	end,
		const bool	indices_are_unique_and_sorted = `false`
	)

inline

Add several nonzero entries to the specified row. Already existing entries are ignored.

Definition at line 965 of file dynamic_sparsity_pattern.h.

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

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

Definition at line 355 of file dynamic_sparsity_pattern.cc.

void DynamicSparsityPattern::symmetrize ( )

Make the sparsity pattern symmetric by adding the sparsity pattern of the transpose object.

This function throws an exception if the sparsity pattern does not represent a square matrix.

Definition at line 375 of file dynamic_sparsity_pattern.cc.

template<typename SparsityPatternTypeLeft , typename SparsityPatternTypeRight >

template void DynamicSparsityPattern::compute_mmult_pattern	(	const SparsityPatternTypeLeft &	left,
		const SparsityPatternTypeRight &	right
	)

Construct and store in this object the sparsity pattern corresponding to the product of left and right sparsity pattern.

Definition at line 410 of file dynamic_sparsity_pattern.cc.

void DynamicSparsityPattern::print ( std::ostream & out ) const

Print the sparsity pattern. 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 439 of file dynamic_sparsity_pattern.cc.

void DynamicSparsityPattern::print_gnuplot ( std::ostream & out ) const

Print the sparsity pattern in a format that gnuplot understands and which can be used to plot the sparsity pattern in a graphical way. The format consists of pairs i j of nonzero elements, each representing one entry, one per line of the output file. Indices are counted from zero on, as usual. Since sparsity patterns are printed in the same way as matrices are displayed, we print the negative of the column index, which means that the (0,0) element is in the top left rather than in the bottom left corner.

Print the sparsity pattern in gnuplot by setting the data style to dots or points and use the plot command.

Definition at line 460 of file dynamic_sparsity_pattern.cc.

DynamicSparsityPattern::size_type DynamicSparsityPattern::n_rows ( ) const

inline

Return the number of rows, which equals the dimension of the image space.

Definition at line 930 of file dynamic_sparsity_pattern.h.

types::global_dof_index DynamicSparsityPattern::n_cols ( ) const

inline

Return the number of columns, which equals the dimension of the range space.

Definition at line 938 of file dynamic_sparsity_pattern.h.

types::global_dof_index DynamicSparsityPattern::row_length ( const size_type row ) const

inline

Number of entries in a specific row. This function can only be called if the given row is a member of the index set of rows that we want to store.

Definition at line 986 of file dynamic_sparsity_pattern.h.

types::global_dof_index DynamicSparsityPattern::column_number	(	const size_type	row,
		const size_type	index
	)		const

inline

Access to column number field. Return the column number of the indexth entry in row.

Definition at line 1004 of file dynamic_sparsity_pattern.h.

DynamicSparsityPattern::iterator DynamicSparsityPattern::begin ( ) const

inline

Iterator starting at the first entry of the matrix. The resulting iterator can be used to walk over all nonzero entries of the sparsity pattern.

Note the discussion in the general documentation of this class about the order in which elements are accessed.

Note: If the sparsity pattern has been initialized with an IndexSet that denotes which rows to store, then iterators will simply skip over rows that are not stored. In other words, they will look like empty rows, but no exception will be generated when iterating over such rows.

Definition at line 1022 of file dynamic_sparsity_pattern.h.

DynamicSparsityPattern::iterator DynamicSparsityPattern::end ( ) const

inline

Final iterator.

Definition at line 1029 of file dynamic_sparsity_pattern.h.

DynamicSparsityPattern::iterator DynamicSparsityPattern::begin ( const size_type r ) const

inline

Iterator starting at the first entry of row r.

Note that if the given row is empty, i.e. does not contain any nonzero entries, then the iterator returned by this function equals end(r). Note also that the iterator may not be dereferencable in that case.

Note also the discussion in the general documentation of this class about the order in which elements are accessed.

Note: If the sparsity pattern has been initialized with an IndexSet that denotes which rows to store, then iterators will simply skip over rows that are not stored. In other words, they will look like empty rows, but no exception will be generated when iterating over such rows.

Definition at line 1037 of file dynamic_sparsity_pattern.h.

DynamicSparsityPattern::iterator DynamicSparsityPattern::end ( const size_type r ) const

inline

Final iterator of row r. It points to the first element past the end of line r, or past the end of the entire sparsity pattern.

Note that the end iterator is not necessarily dereferencable. This is in particular the case if it is the end iterator for the last row of a matrix.

Definition at line 1095 of file dynamic_sparsity_pattern.h.

DynamicSparsityPattern::size_type DynamicSparsityPattern::bandwidth ( ) const

Compute the bandwidth of the matrix represented by this structure. The bandwidth is the maximum of \(|i-j|\) for which the index pair \((i,j)\) represents a nonzero entry of the matrix.

Definition at line 486 of file dynamic_sparsity_pattern.cc.

DynamicSparsityPattern::size_type DynamicSparsityPattern::n_nonzero_elements ( ) const

Return the number of nonzero elements allocated through this sparsity pattern.

Definition at line 509 of file dynamic_sparsity_pattern.cc.

const IndexSet & DynamicSparsityPattern::row_index_set ( ) const

inline

Return the IndexSet that sets which rows are active on the current processor. It corresponds to the IndexSet given to this class in the constructor or in the reinit function.

Definition at line 1109 of file dynamic_sparsity_pattern.h.

bool DynamicSparsityPattern::stores_only_added_elements ( )

inlinestatic

return whether this object stores only those entries that have been added explicitly, or if the sparsity pattern contains elements that have been added through other means (implicitly) while building it. For the current class, the result is always true.

This function mainly serves the purpose of describing the current class in cases where several kinds of sparsity patterns can be passed as template arguments.

Definition at line 1117 of file dynamic_sparsity_pattern.h.

DynamicSparsityPattern::size_type DynamicSparsityPattern::memory_consumption ( ) const

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

Definition at line 525 of file dynamic_sparsity_pattern.cc.