Dune::Std Namespace Reference

Namespace for features backported from new C++ standards. More...

Classes
struct	compare_three_way
	A functor implementing the three-way comparison on the arguments. More...
class	default_accessor
	A type for indexed access to elements of mdspan.The default_accessor class template is the default AccessorPolicy used by mdspan if no user-specified accessor policy is provided. More...
class	extents
	Multidimensional index space with dynamic and static extents.This class template represents a multidimensional index space of rank equal to sizeof...(exts). Each extent might be specified as a template parameter or as a dynamic parameter in the constructor. More...
struct	identity
	A function object type whose operator() returns its argument unchanged. More...
struct	layout_left
	A layout where the leftmost extent has stride 1.For two-dimensional tensors this corresponds to column-major indexing. More...
struct	layout_right
	A layout where the rightmost extent has stride 1, and strides increase right-to-left as the product of extents.For two-dimensional tensors this corresponds to row-major indexing. More...
struct	layout_stride
	A layout mapping where the strides are user-defined. More...
class	mdarray
	An owning multi-dimensional array analog of mdspan. More...
class	mdspan
	A multi-dimensional non-owning array view. More...
struct	nonesuch
	Type representing a lookup failure by std::detected_or and friends. More...
class	span
	A contiguous sequence of elements with static or dynamic extent. More...

Typedefs
template<class IndexType , std::size_t R>
using	dextents = typename Impl::DExtentsImpl< IndexType, std::make_integer_sequence< std::size_t, R > >::type
	Alias of extents of given rank R and purely dynamic extents. See [mdspan.extents.dextents]. More...
template<typename Default , template< typename... > class Op, typename... Args>
using	detected_or = Impl::detector< Default, void, Op, Args... >
	Detects whether Op<Args...> is valid and makes the result available. More...
template<template< typename... > class Op, typename... Args>
using	is_detected = typename detected_or< nonesuch, Op, Args... >::value_t
	Detects whether Op<Args...> is valid. More...
template<template< typename... > class Op, typename... Args>
using	detected_t = typename detected_or< nonesuch, Op, Args... >::type
	Returns Op<Args...> if that is valid; otherwise returns nonesuch. More...
template<typename Default , template< typename... > class Op, typename... Args>
using	detected_or_t = typename detected_or< Default, Op, Args... >::type
	Returns Op<Args...> if that is valid; otherwise returns the fallback type Default. More...
template<typename Expected , template< typename... > class Op, typename... Args>
using	is_detected_exact = std::is_same< Expected, detected_t< Op, Args... > >
	Checks whether Op<Args...> is Expected without causing an error if Op<Args...> is invalid. More...
template<typename Target , template< typename... > class Op, typename... Args>
using	is_detected_convertible = std::is_convertible< Target, detected_t< Op, Args... > >
	Checks whether Op<Args...> is convertible to Target without causing an error if Op<Args...> is invalid. More...

Functions
template<class I1 , class I2 , class Cmp = Std::compare_three_way>
constexpr auto	lexicographical_compare_three_way (I1 f1, I1 l1, I2 f2, I2 l2, Cmp comp={}) -> decltype(comp(*f1, *f2))
	Lexicographically compares two ranges [first1, last1) and [first2, last2) using three-way comparison and produces a result of the strongest applicable comparison category type. More...
template<class T >
constexpr T	abs (T t)
template<class T >
constexpr auto	sqrt (T t) requires(std
template<class T >
constexpr auto	to_address (T &&p) noexcept
	Obtain the address represented by p without forming a reference to the object pointed to by p. More...
template<class CArray , std::enable_if_t< std::is_array_v< CArray >, int > = 0, std::enable_if_t<(std::rank_v< CArray >==1), int > = 0>
	mdspan (CArray &) -> mdspan< std::remove_all_extents_t< CArray >, Std::extents< std::size_t, std::extent_v< CArray, 0 >>>
template<class Pointer , std::enable_if_t< std::is_pointer_v< std::remove_reference_t< Pointer >>, int > = 0>
	mdspan (Pointer &&) -> mdspan< std::remove_pointer_t< std::remove_reference_t< Pointer >>, Std::extents< std::size_t >>
template<class ElementType , class... II, std::enable_if_t<(... &&std::is_convertible_v< II, std::size_t >), int > = 0, std::enable_if_t<(sizeof...(II) > 0>
	mdspan (ElementType *, II...) -> mdspan< ElementType, Std::dextents< std::size_t, sizeof...(II)>>
template<class ElementType , class SizeType , std::size_t N>
	mdspan (ElementType *, std::span< SizeType, N >) -> mdspan< ElementType, Std::dextents< std::size_t, N >>
template<class ElementType , class SizeType , std::size_t N>
	mdspan (ElementType *, const std::array< SizeType, N > &) -> mdspan< ElementType, Std::dextents< std::size_t, N >>
template<class ElementType , class IndexType , std::size_t... exts>
	mdspan (ElementType *, const Std::extents< IndexType, exts... > &) -> mdspan< ElementType, Std::extents< IndexType, exts... >>
template<class ElementType , class Mapping , class Extents = typename Mapping::extents_type, class Layout = typename Mapping::layout_type>
	mdspan (ElementType *, const Mapping &) -> mdspan< ElementType, Extents, Layout >
template<class Mapping , class Accessor , class DataHandle = typename Accessor::data_handle_type, class Element = typename Accessor::element_type, class Extents = typename Mapping::extents_type, class Layout = typename Mapping::layout_type>
	mdspan (const DataHandle &, const Mapping &, const Accessor &) -> mdspan< Element, Extents, Layout, Accessor >
template<class T , std::size_t N>
	span (T(&)[N]) -> span< T, N >
template<class ElementType , class I , std::size_t Extent, std::enable_if_t< std::is_convertible_v< I, std::size_t >, int > = 0>
	span (ElementType *, std::integral_constant< I, Extent >) -> span< ElementType, Extent >
template<class ElementType , class I , std::enable_if_t< std::is_integral_v< I >, int > = 0, std::enable_if_t< std::is_convertible_v< I, std::size_t >, int > = 0>
	span (ElementType *, I) -> span< ElementType, Std::dynamic_extent >
template<class Iter , class Element = std::remove_reference_t<decltype(*std::declval<Iter>())>>
	span (Iter, Iter) -> span< Element, Std::dynamic_extent >
template<class Range , class First = decltype(std::begin(std::declval<Range>())), class Last = decltype(std::end(std::declval<Range>())), class Element = std::remove_reference_t<decltype(*std::declval<First>())>>
	span (Range &) -> span< Element, Std::dynamic_extent >
template<class T , size_t N>
	span (std::array< T, N > &) -> span< T, N >
template<class T , size_t N>
	span (const std::array< T, N > &) -> span< const T, N >

Variables
template<class T , class Cat = std::partial_ordering>
concept	three_way_comparable
	The concept std::three_way_comparable specifies that the three way comparison operator <=> on T yield results consistent with the comparison category implied by Cat. More...
template<class T , class U , class Cat = std::partial_ordering>
concept	three_way_comparable_with
	The concept std::three_way_comparable_with specifies that the three way comparison operator <=> on (possibly mixed) T and U operands yield results consistent with the comparison category implied by Cat. Comparing mixed operands yields results equivalent to comparing the operands converted to their common type. More...
template<class In , class Out >
concept	indirectly_copyable
	The std::indirectly_copyable concept specifies the relationship between an indirectly_readable type and a type that is indirectly_writable. The indirectly_writable type must be able to directly copy the object that the indirectly_readable type references. More...
constexpr std::size_t	dynamic_extent = std::dynamic_extent
	A constant of type std::size_t that is used to differentiate std::span of static and dynamic extent. More...

Detailed Description

Namespace for features backported from new C++ standards.

The namespace Dune::Std contains library features of new C++ standards and technical specifications backported to older compilers. Most features are detected and pulled into this namespace from the standard library if your compiler has native support. If it doesn't, we provide a fallback implementation on a best-effort basis.

Function Documentation

abs()

template<class T >

constexpr T Dune::Std::abs

(

T

t

)

lexicographical_compare_three_way()

template<class I1 , class I2 , class Cmp = Std::compare_three_way>

constexpr auto Dune::Std::lexicographical_compare_three_way	(	I1	f1,
		I1	l1,
		I2	f2,
		I2	l2,
		Cmp	comp = {}
	)		-> decltype(comp(*f1, *f2))

Lexicographically compares two ranges [first1, last1) and [first2, last2) using three-way comparison and produces a result of the strongest applicable comparison category type.

Implementation taken from https://en.cppreference.com/w/cpp/algorithm/lexicographical_compare_three_way

The standard implementation is available with libstdc++ >= 10 and libc++ >= 17

mdspan() [1/8]

template<class CArray , std::enable_if_t< std::is_array_v< CArray >, int > = 0, std::enable_if_t<(std::rank_v< CArray >==1), int > = 0>

Dune::Std::mdspan

(

CArray &

)

-> mdspan< std::remove_all_extents_t< CArray >, Std::extents< std::size_t, std::extent_v< CArray, 0 >>>

mdspan() [2/8]

template<class Pointer , std::enable_if_t< std::is_pointer_v< std::remove_reference_t< Pointer >>, int > = 0>

Dune::Std::mdspan

(

Pointer &&

)

-> mdspan< std::remove_pointer_t< std::remove_reference_t< Pointer >>, Std::extents< std::size_t >>

mdspan() [3/8]

template<class ElementType , class... II, std::enable_if_t<(... &&std::is_convertible_v< II, std::size_t >), int > = 0, std::enable_if_t<(sizeof...(II) > 0>

Dune::Std::mdspan	(	ElementType *	,
		II...
	)		-> mdspan< ElementType, Std::dextents< std::size_t, sizeof...(II)>>

mdspan() [4/8]

template<class ElementType , class SizeType , std::size_t N>

Dune::Std::mdspan	(	ElementType *	,
		std::span< SizeType, N >
	)		-> mdspan< ElementType, Std::dextents< std::size_t, N >>

mdspan() [5/8]

template<class ElementType , class SizeType , std::size_t N>

Dune::Std::mdspan	(	ElementType *	,
		const std::array< SizeType, N > &
	)		-> mdspan< ElementType, Std::dextents< std::size_t, N >>

mdspan() [6/8]

template<class ElementType , class IndexType , std::size_t... exts>

Dune::Std::mdspan	(	ElementType *	,
		const Std::extents< IndexType, exts... > &
	)		-> mdspan< ElementType, Std::extents< IndexType, exts... >>

mdspan() [7/8]

template<class ElementType , class Mapping , class Extents = typename Mapping::extents_type, class Layout = typename Mapping::layout_type>

Dune::Std::mdspan	(	ElementType *	,
		const Mapping &
	)		-> mdspan< ElementType, Extents, Layout >

mdspan() [8/8]

template<class Mapping , class Accessor , class DataHandle = typename Accessor::data_handle_type, class Element = typename Accessor::element_type, class Extents = typename Mapping::extents_type, class Layout = typename Mapping::layout_type>

Dune::Std::mdspan	(	const DataHandle &	,
		const Mapping &	,
		const Accessor &
	)		-> mdspan< Element, Extents, Layout, Accessor >

span() [1/7]

template<class T , std::size_t N>

Dune::Std::span

(

T(&)

[N]

)

-> span< T, N >

span() [2/7]

template<class ElementType , class I , std::size_t Extent, std::enable_if_t< std::is_convertible_v< I, std::size_t >, int > = 0>

Dune::Std::span	(	ElementType *	,
		std::integral_constant< I, Extent >
	)		-> span< ElementType, Extent >

span() [3/7]

template<class ElementType , class I , std::enable_if_t< std::is_integral_v< I >, int > = 0, std::enable_if_t< std::is_convertible_v< I, std::size_t >, int > = 0>

Dune::Std::span	(	ElementType *	,
		I
	)		-> span< ElementType, Std::dynamic_extent >

span() [4/7]

template<class Iter , class Element = std::remove_reference_t<decltype(*std::declval<Iter>())>>

Dune::Std::span	(	Iter	,
		Iter
	)		-> span< Element, Std::dynamic_extent >

span() [5/7]

template<class Range , class First = decltype(std::begin(std::declval<Range>())), class Last = decltype(std::end(std::declval<Range>())), class Element = std::remove_reference_t<decltype(*std::declval<First>())>>

Dune::Std::span

(

Range &

)

-> span< Element, Std::dynamic_extent >

span() [6/7]

template<class T , size_t N>

Dune::Std::span

(

std::array< T, N > &

)

-> span< T, N >

span() [7/7]

template<class T , size_t N>

Dune::Std::span

(

const std::array< T, N > &

)

-> span< const T, N >

sqrt()

template<class T >

constexpr auto Dune::Std::sqrt

(

T

t

)

to_address()

template<class T >

constexpr auto Dune::Std::to_address ( T &&  p )

noexcept

Obtain the address represented by p without forming a reference to the object pointed to by p.

Variable Documentation

dynamic_extent

constexpr std::size_t Dune::Std::dynamic_extent = std::dynamic_extent

inline

A constant of type std::size_t that is used to differentiate std::span of static and dynamic extent.

indirectly_copyable

template<class In , class Out >

concept Dune::Std::indirectly_copyable

Initial value:

=
    std::indirectly_readable<In> &&
    std::indirectly_writable<Out, std::iter_reference_t<In>>

The std::indirectly_copyable concept specifies the relationship between an indirectly_readable type and a type that is indirectly_writable. The indirectly_writable type must be able to directly copy the object that the indirectly_readable type references.

The standard implementation is available in libstdc++ >= 10 and libc++ >= 15

three_way_comparable

template<class T , class Cat = std::partial_ordering>

concept Dune::Std::three_way_comparable

Initial value:

=
  Impl::weaklyEqualityComparableWith<T, T> &&
  Impl::partiallyOrderedWith<T, T> &&
  requires(const std::remove_reference_t<T>& a,
           const std::remove_reference_t<T>& b)
  {
    { a <=> b } -> Impl::comparesAs<Cat>;
  }

The concept std::three_way_comparable specifies that the three way comparison operator <=> on T yield results consistent with the comparison category implied by Cat.

The standard implementation is available in libstdc++ >= 10 and libc++ >= 14.

three_way_comparable_with

template<class T , class U , class Cat = std::partial_ordering>

concept Dune::Std::three_way_comparable_with

Initial value:

=
  Std::three_way_comparable<T, Cat> &&
  Std::three_way_comparable<U, Cat> &&
  Impl::comparisonCommonTypeWith<T, U> &&
  Std::three_way_comparable<
    std::common_reference_t<
      const std::remove_reference_t<T>&,
      const std::remove_reference_t<U>&>, Cat> &&
  Impl::weaklyEqualityComparableWith<T, U> &&
  Impl::partiallyOrderedWith<T, U> &&
  requires(const std::remove_reference_t<T>& t,
           const std::remove_reference_t<U>& u)
  {
    { t <=> u } -> Impl::comparesAs<Cat>;
    { u <=> t } -> Impl::comparesAs<Cat>;
  }

The concept std::three_way_comparable_with specifies that the three way comparison operator <=> on (possibly mixed) T and U operands yield results consistent with the comparison category implied by Cat. Comparing mixed operands yields results equivalent to comparing the operands converted to their common type.

The standard implementation is available in libstdc++ >= 10 and libc++ >= 14.