29 Numerics library [numerics]

29.9 Basic linear algebra algorithms [linalg]

29.9.9 Conjugated in-place transformation [linalg.conj]

29.9.9.3 Function template conjugated [linalg.conj.conjugated]

  template<class ElementType, class Extents, class Layout, class Accessor>
    constexpr auto conjugated(mdspan<ElementType, Extents, Layout, Accessor> a);

Let A be

(1.1)
remove_cvref_t<decltype(a.accessor().nested_accessor())> if Accessor is a specialization of conjugated_accessor;
(1.2)
otherwise, Accessor if remove_cvref_t<ElementType> is an arithmetic type;
(1.3)
otherwise, conjugated_accessor<Accessor> if the expression conj(E) is valid for any subexpression E whose type is remove_cvref_t<ElementType> with overload resolution performed in a context that includes the declaration template<class U> U conj(const U&) = delete;;
(1.4)
otherwise, Accessor.

Returns: Let MD be mdspan<typename A::element_type, Extents, Layout, A>.

(2.1)
MD(a.data_handle(), a.mapping(), a.accessor().nested_accessor()) if Accessor is a
specialization of conjugated_accessor;
(2.2)
otherwise, a, if is_same_v<A, Accessor> is true;
(2.3)
otherwise, MD(a.data_handle(), a.mapping(), conjugated_accessor(a.accessor())).

[Example 1: void test_conjugated_complex(mdspan<complex<double>, extents<int, 10>> a) { auto a_conj = conjugated(a); for (int i = 0; i < a.extent(0); ++i) { assert(a_conj[i] == conj(a[i]); } auto a_conj_conj = conjugated(a_conj); for (int i = 0; i < a.extent(0); ++i) { assert(a_conj_conj[i] == a[i]); } } void test_conjugated_real(mdspan<double, extents<int, 10>> a) { auto a_conj = conjugated(a); for (int i = 0; i < a.extent(0); ++i) { assert(a_conj[i] == a[i]); } auto a_conj_conj = conjugated(a_conj); for (int i = 0; i < a.extent(0); ++i) { assert(a_conj_conj[i] == a[i]); } } — end example]