std::extents, std::dextents
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| Defined in header <mdspan>
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| 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) |
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<TypeIndex, Rank> is equivalent to extents<IndexType /*, d, d, ..., d*/> (i.e. d is repeated a total of Rank times).Each specialization of extents models regular and is TriviallyCopyable.
Contents |
[edit] Template parameters
| IndexType | - | the type of each non-dynamic Extents. Shall be a signed or unsigned integer type. Otherwise, the program is ill-formed
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| 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
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| Rank | - | denotes the rank of an all-dynamic extents
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[edit] Member types
| Member type | Definition |
index_type
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IndexType
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size_type
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std::make_unsigned_t<index_type> |
rank_type
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std::size_t |
[edit] Data members
dynamic-extents (private)
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An array of type std::array<index_type, rank_dynamic()>, which stores the size of each dynamic extents. (exposition-only member object*) |
[edit] 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*) |
[edit] Non-member functions
| (C++23) |
compare underlying extents in each dimension of two extents (function) |
[edit] Deduction guides(C++23)
[edit] Example
| This section is incomplete Reason: no example |
[edit] 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) |
