std::extents, std::dextents, std::dims

 

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std::mdspan

Member functions mdspan::mdspan mdspan::operator= Element access mdspan::operator[] Observers mdspan::rank mdspan::rank_dynamic mdspan::static_extent mdspan::extent mdspan::size mdspan::empty mdspan::stride mdspan::extents mdspan::data_handle mdspan::mapping mdspan::accessor mdspan::is_uniquemdspan::is_exhaustivemdspan::is_stridedmdspan::is_always_uniquemdspan::is_always_exhaustivemdspan::is_always_strided

Non-member functions swap(std::mdspan) Subviews submdspan (C++26) submdspan_extents (C++26) Helper types and templates extentsdextentsdims (C++26) default_accessor Layout mapping policies layout_left layout_right layout_stride layout_left_padded (C++26) layout_right_padded (C++26) Subviews helpers full_extent (C++26) strided_slice (C++26) submdspan_mapping_result (C++26) Deduction guides

 

std::extents

Member functions

extents::extents

Observers

extents::rank

extents::rank_dynamic

extents::static_extent

extents::extent

Helpers

extents::fwd-prod-of-extents

extents::rev-prod-of-extents

extents::index-cast

extents::dynamic-index

extents::dynamic-index-inv

Non-member functions

extents::operator==

Deduction guides

 

Defined in header <mdspan>
template< class IndexType, std::size_t... Extents > class extents;	(1)	(since C++23)
template< class IndexType, std::size_t Rank > using dextents = /* see below */	(2)	(since C++23)
template< std::size_t Rank, class IndexType = std::size_t > using dims = std::dextents<IndexType, Rank>;	(3)	(since C++26)

1) Represents a multidimensional index space of rank equal to sizeof...(Extents).

2) A convenient alias template for an all-dynamic extents. Let d denote std::dynamic_extent, each specialization of it dextents<IndexType, Rank> is equivalent to extents<IndexType /*, d, d, ..., d*/> (i.e. d is repeated a total of Rank times).

3) A convenient alias template for an all-dynamic extents with std::size_t as the default index type.

Each specialization of extents models regular and is TriviallyCopyable.

Template parameters

IndexType	-	the type of each non-dynamic Extents. Shall be a signed or unsigned integer type. Otherwise, the program is ill-formed
Extents	-	represents extent (size of an integer interval) for each rank index. Each element of it is either equal to std::dynamic_extent (in this case, it represents a dynamic extent and the extent size will be determined dynamically), or is representable as a value of type IndexType (then it represents a static extent and the extent size is just the value of it), or else the program is ill-formed
Rank	-	denotes the rank of an all-dynamic extents

Member types

Member type	Definition
index_type	IndexType
size_type	std::make_unsigned_t<index_type>
rank_type	std::size_t

Data members

Member name	Definition
std::array<index_type, rank_dynamic()> dynamic-extents (private)	An array which stores the size of each dynamic extents. (exposition-only member object*)

Member functions

(constructor)	constructs an extents (public member function)
Observers
rank [static]	returns the static rank of an extents (public static member function)
rank_dynamic [static]	returns the dynamic rank of an extents (public static member function)
static_extent [static]	returns static extent size of an extents at a certain rank index (public static member function)
extent	returns dynamic extent size of an extents at a certain rank index (public member function)
Helpers
fwd-prod-of-extents	returns the product of extent size in range [​0​, i) (exposition-only member function*)
rev-prod-of-extents	returns the product of extents size in range [i + 1, rank()) (exposition-only member function*)
index-cast	casts the input into an integer type (exposition-only member function*)
dynamic-index (private)	returns the number of dynamic extents below a certain rank index (exposition-only member function*)
dynamic-index-inv (private)	returns the number r such that in range [​0​, r + 1) there is exactly i + 1 dynamic extents for a certain argument i (exposition-only member function*)

Non-member functions

operator== (C++23)

compare underlying extents in each dimension of two extents (function)

See also

rank (C++11)	obtains the number of dimensions of an array type (class template)
extent (C++11)	obtains the size of an array type along a specified dimension (class template)