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

Inheritance diagram for SparsityPatternIterators::Iterator:

Public Types
using	size_type = types::global_dof_index

using	container_pointer_type = SparsityPatternBase *

Public Types inherited from LinearIndexIterator< Iterator, Accessor >
using	iterator_category = std::random_access_iterator_tag

using	value_type = Accessor

using	difference_type = std::ptrdiff_t

using	reference = const value_type &

using	pointer = const value_type *

using	size_type = typename value_type::size_type

Public Member Functions
	Iterator (const SparsityPatternBase *sp, const std::size_t linear_index)

	Iterator (const Accessor &accessor)

Public Member Functions inherited from LinearIndexIterator< Iterator, Accessor >
Iterator &	operator= (const Iterator &it)

Iterator &	operator++ ()

Iterator	operator++ (int)

Iterator &	operator-- ()

Iterator	operator-- (int)

Iterator	operator+ (const difference_type n) const

Iterator	operator- (const difference_type n) const

difference_type	operator- (const Iterator &p) const

Iterator &	operator+= (const difference_type n)

Iterator &	operator-= (const difference_type n)

reference	operator* () const

pointer	operator-> () const

bool	operator== (const Iterator &) const

bool	operator!= (const Iterator &) const

bool	operator<= (const Iterator &) const

bool	operator>= (const Iterator &) const

bool	operator< (const Iterator &) const

bool	operator> (const Iterator &) const

Additional Inherited Members
Protected Member Functions inherited from LinearIndexIterator< Iterator, Accessor >
	LinearIndexIterator (const Accessor accessor)

Protected Attributes inherited from LinearIndexIterator< Iterator, Accessor >
Accessor	accessor

Detailed Description

An iterator class for walking over the elements of a sparsity pattern.

The typical use for these iterators is to iterate over the elements of a sparsity pattern (or, since they also serve as the basis for iterating over the elements of an associated matrix, over the elements of a sparse matrix), or over the elements of individual rows. There is no guarantee that the elements of a row are actually traversed in an order in which column numbers monotonically increase. See the documentation of the SparsityPattern class for more information.

Note: This class operates directly on the internal data structures of the SparsityPatternBase class. As a consequence, some operations are cheap and some are not. In particular, it is cheap to access the column index of the sparsity pattern entry pointed to. On the other hand, it is expensive to access the row index (this requires \(O(\log(N))\) operations for a matrix with \(N\) row). As a consequence, when you design algorithms that use these iterators, it is common practice to not loop over all elements of a sparsity pattern at once, but to have an outer loop over all rows and within this loop iterate over the elements of this row. This way, you only ever need to dereference the iterator to obtain the column indices whereas the (expensive) lookup of the row index can be avoided by using the loop index instead.

Definition at line 283 of file sparsity_pattern.h.

Member Typedef Documentation

◆ size_type

using SparsityPatternIterators::Iterator::size_type = types::global_dof_index

Size type.

Definition at line 289 of file sparsity_pattern.h.

◆ container_pointer_type

using SparsityPatternIterators::Iterator::container_pointer_type = SparsityPatternBase *

Type of the stored pointer.

Definition at line 294 of file sparsity_pattern.h.

Constructor & Destructor Documentation

◆ Iterator() [1/2]

SparsityPatternIterators::Iterator::Iterator	(	const SparsityPatternBase *	sp,
		const std::size_t	linear_index
	)

Constructor. Create an iterator into the sparsity pattern sp for the given global index (i.e., the index of the given element counting from the zeroth row).

◆ Iterator() [2/2]

SparsityPatternIterators::Iterator::Iterator ( const Accessor & accessor )

Constructor. Create an iterator into the sparsity pattern sp for a given accessor.

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

deal.II/lac/sparsity_pattern.h

Public Types

Public Member Functions