std::mdspan<T,Extents,LayoutPolicy,AccessorPolicy>::operator[]

 

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Symbols index

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span (C++20)

mdspan (C++23)

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std::mdspan

Member functions

mdspan::mdspan (C++23)

mdspan::operator= (C++23)

Element access

mdspan::operator[] (C++23)

Observers

mdspan::size (C++23)

mdspan::empty (C++23)

mdspan::stride (C++23)

mdspan::extents (C++23)

mdspan::data_handle (C++23)

mdspan::mapping (C++23)

mdspan::accessor (C++23)

mdspan::is_uniquemdspan::is_exhaustivemdspan::is_stridedmdspan::is_always_uniquemdspan::is_always_exhaustivemdspan::is_always_strided (C++23)(C++23)(C++23)(C++23)(C++23)(C++23)

Non-member functions

swap (C++23)

Helper types and templates

extentsdextents (C++23)(C++23)

layout_right (C++23)

layout_left (C++23)

layout_stride (C++23)

default_accessor (C++23)

Deduction guides(C++23)

 

template< class... OtherIndexTypes > constexpr reference operator[]( OtherIndexTypes... indices ) const;	(1)	(since C++23)
template< class OtherIndexType > constexpr reference operator[]( std::span<OtherIndexType, rank()> indices ) const;	(2)	(since C++23)
template< class OtherIndexType > constexpr reference operator[]( const std::array<OtherIndexType, rank()>& indices ) const;	(3)	(since C++23)

Returns a reference to the indices^th element of the mdspan.

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

• This overload participates in overload resolution only if:

• (std::is_convertible_v<OtherIndexTypes, index_type> && ...) is true,
• (std::is_nothrow_constructible_v<index_type, OtherIndexTypes> && ...) is true, and
• sizeof...(OtherIndexTypes) == rank() is true.

• Let I be extents_type::index-cast(std::move(indices)). Then the behavior is undefined if I is not a multidimensional index in extents(), i.e., map_(I) < map_.required_span_size() is false.

2,3) Let P be a parameter pack such that std::is_same_v<make_index_sequence<rank()>, index_sequence<P...>> is true, then the operator is equivalent to return operator[](std::as_const(indices[P])...);.

• This overload participates in overload resolution only if:

• std::is_convertible_v<const OtherIndexType&, index_type> is true, and
• std::is_nothrow_constructible_v<index_type, const OtherIndexType&> is true.

Parameters

indices

-

the indices of the element to access

Return value

A reference to the element