23 Containers library [containers]

23.7 Views [views]

23.7.3 Multidimensional access [views.multidim]

23.7.3.6 Class template mdspan [mdspan.mdspan]

23.7.3.6.3 Members [mdspan.mdspan.members]

template<class... OtherIndexTypes>
  constexpr reference operator[](OtherIndexTypes... indices) const;

Constraints:

(1.1)
(is_convertible_v<OtherIndexTypes, index_type> && ...) is true,
(1.2)
(is_nothrow_constructible_v<index_type, OtherIndexTypes> && ...) is true, and
(1.3)
sizeof...(OtherIndexTypes) == rank() is true.

Let I be extents_type::index-cast(std::move(indices)).

Preconditions: I is a multidimensional index in extents().

[Note 1:

This implies that map_(I) < map_.required_span_size() is true.

— end note]

Effects: Equivalent to: return acc_.access(ptr_, map_(static_cast<index_type>(std::move(indices))...));

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template<class OtherIndexType>
  constexpr reference operator[](span<OtherIndexType, rank()> indices) const;
template<class OtherIndexType>
  constexpr reference operator[](const array<OtherIndexType, rank()>& indices) const;

Constraints:

(5.1)
is_convertible_v<const OtherIndexType&, index_type> is true, and
(5.2)
is_nothrow_constructible_v<index_type, const OtherIndexType&> is true.

Effects: Let P be a parameter pack such that is_same_v<make_index_sequence<rank()>, index_sequence<P...>> is true.

Equivalent to: return operator[](extents_type::index-cast(as_const(indices[P]))...);

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constexpr size_type size() const noexcept;

Preconditions: The size of the multidimensional index space extents() is representable as a value of type size_type ([basic.fundamental]).

Returns: extents().fwd-prod-of-extents(rank()).

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constexpr bool empty() const noexcept;

Returns: true if the size of the multidimensional index space extents() is 0, otherwise false.

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friend constexpr void swap(mdspan& x, mdspan& y) noexcept;

Effects: Equivalent to: swap(x.ptr_, y.ptr_); swap(x.map_, y.map_); swap(x.acc_, y.acc_);