24 Containers library [containers]

24.7 Views [views]

24.7.3 Multidimensional access [views.multidim] Layout mapping [mdspan.layout] Class template layout_stride​::​mapping [mdspan.layout.stride] Observers [mdspan.layout.stride.obs]

constexpr index_type required_span_size() const noexcept;
Returns: REQUIRED-SPAN-SIZE(extents(), strides_).
template<class... Indices> constexpr index_type operator()(Indices... i) const noexcept;
  • sizeof...(Indices) == rank_ is true,
  • (is_convertible_v<Indices, index_type> && ...) is true, and
  • (is_nothrow_constructible_v<index_type, Indices> && ...) is true.
Preconditions: extents_type​::​index-cast(i) is a multidimensional index in extents_ ([mdspan.overview]).
Effects: Let P be a parameter pack such that is_same_v<index_sequence_for<Indices...>, index_sequence<P...>> is true.
Equivalent to: return ((static_cast<index_type>(i) * stride(P)) + ... + 0);
constexpr bool is_exhaustive() const noexcept;
  • true if rank_ is 0.
  • Otherwise, true if there is a permutation P of the integers in the range [0, rank_) such that stride() equals 1, and stride() equals stride() * extents().extent() for i in the range [1, rank_), where is the element of P.
  • Otherwise, false.
template<class OtherMapping> friend constexpr bool operator==(const mapping& x, const OtherMapping& y) noexcept;
Preconditions: OtherMapping meets the layout mapping requirements ([mdspan.layout.policy.reqmts]).
Returns: true if x.extents() == y.extents() is true, OFFSET(y) == 0 is true, and each of x.stride(r) == y.stride(r) is true for r in the range [0, x.extents().rank()).
Otherwise, false.