29 Numerics library [numerics]

29.9 Basic linear algebra algorithms [linalg]

29.9.6 Layouts for packed matrix types [linalg.layout.packed]

29.9.6.2 Constructors [linalg.layout.packed.cons]

constexpr mapping(const extents_type& e) noexcept;
Preconditions:
Effects: Direct-non-list-initializes extents_ with e.
template<class OtherExtents> explicit(!is_convertible_v<OtherExtents, extents_type>) constexpr mapping(const mapping<OtherExtents>& other) noexcept;
Constraints: is_constructible_v<extents_type, OtherExtents> is true.
Preconditions: Let N be other.extents().extent(0).
Then, is representable as a value of type index_type ([basic.fundamental]).
Effects: Direct-non-list-initializes extents_ with other.extents().