24 Containers library [containers]

24.7 Views [views]

24.7.3 Multidimensional access [views.multidim]

24.7.3.4 Layout mapping [mdspan.layout]

24.7.3.4.7 Class template layout_stride::mapping [mdspan.layout.stride]

24.7.3.4.7.3 Constructors [mdspan.layout.stride.cons]

constexpr mapping() noexcept;

Preconditions: layout_right::mapping<extents_type>().required_span_size() is representable as a value of type index_type ([basic.fundamental]).

Effects: Direct-non-list-initializes extents_ with extents_type(), and for all d in the range [0, rank_), direct-non-list-initializes strides_[d] with layout_right::mapping<extents_type>().stride(d).

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template<class OtherIndexType>
  constexpr mapping(const extents_type& e, span<OtherIndexType, rank_> s) noexcept;
template<class OtherIndexType>
  constexpr mapping(const extents_type& e, const array<OtherIndexType, rank_>& s) noexcept;

Constraints:

(3.1)
is_convertible_v<const OtherIndexType&, index_type> is true, and
(3.2)
is_nothrow_constructible_v<index_type, const OtherIndexType&> is true.

Preconditions:

(4.1)
The result of converting s[i] to index_type is greater than 0 for all i in the range [0, rank_).
(4.2)
REQUIRED-SPAN-SIZE(e, s) is representable as a value of type index_type ([basic.fundamental]).
(4.3)
If rank_ is greater than 0, then there exists a permutation P of the integers in the range [0, rank_), such that s[ $p_{i}$ ] >= s[ $p_{i - 1}$ ] * e.extent(p $_{i - 1}$ ) is true for all i in the range [1, rank_), where $p_{i}$ is the $i^{th}$ element of P.

[Note 1:
For layout_stride, this condition is necessary and sufficient for is_unique() to be true.
— end note]

Effects: Direct-non-list-initializes extents_ with e, and for all d in the range [0, rank_), direct-non-list-initializes strides_[d] with as_const(s[d]).

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template<class StridedLayoutMapping>
  constexpr explicit(see below)
    mapping(const StridedLayoutMapping& other) noexcept;