std::extents, std::dextents, std::
From cppreference.com
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
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
|
| 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
constructs an extents (public member function) |
|
Observers | |
|
[static]
|
returns the static rank of an extents (public static member function) |
|
[static]
|
returns the dynamic rank of an extents (public static member function) |
|
[static]
|
returns static extent size of an extents at a certain rank index (public static member function) |
returns dynamic extent size of an extents at a certain rank index (public member function) |
|
Helpers | |
returns the product of extent size in range [0, i)
(exposition-only member function* |
|
returns the product of extents size in range
[
i + 1
,
rank()
)
(exposition-only member function* |
|
| casts the input into an integer type (exposition-only member function* |
|
|
(private)
|
returns the number of dynamic extents below a certain rank index (exposition-only member function* |
|
(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
|
(C++23)
|
compare underlying extents in each dimension of two extents (function) |
Deduction guides(C++23)
Example
| This section is incomplete Reason: no example |
See also
|
(C++11)
|
obtains the number of dimensions of an array type (class template) |
|
(C++11)
|
obtains the size of an array type along a specified dimension (class template) |