#include <gromacs/mdspan/mdspan.h>

Description

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>
class gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >

Multidimensional array indexing and memory access with flexible mapping and access model.

Template Parameters

ElementType	Type of elemnt to be viewed
Extents	The dimensions of the multidimenisonal array to view.
LayoutPolicy	Describes is the memory layout of the multidimensional array; right by default.
AccessorPolicy	Describes memory access model.

Public Types
using	extents_type = Extents
	Expose type used to define the extents of the data.

using	layout_type = LayoutPolicy
	Expose type used to define the layout of the data.

using	accessor_type = AccessorPolicy
	Expose type used to define the memory access model of the data.

using	mapping_type = typename layout_type::template mapping< extents_type >
	Expose type used to map multidimensional indices to one-dimensioal indices.

using	element_type = typename accessor_type::element_type
	Exposes the type of stored element.

using	value_type = std::remove_cv_t< element_type >
	Expose the underlying type of the stored elements.

using	index_type = ptrdiff_t
	Expose the type used for indexing.

using	difference_type = ptrdiff_t
	Expose type for index differences.

using	pointer = typename accessor_type::pointer
	Expose underlying pointer to data type.

using	reference = typename accessor_type::reference
	Expose reference to data type.

Public Member Functions
constexpr	basic_mdspan () noexcept
	Trivial constructor.

constexpr	basic_mdspan (basic_mdspan &&other) noexcept=default
	Move constructor.

constexpr	basic_mdspan (const basic_mdspan &other) noexcept=default
	copy constructor

basic_mdspan &	operator= (const basic_mdspan &other) noexcept=default
	Copy assignment.

basic_mdspan &	operator= (basic_mdspan &&other) noexcept=default
	Move assignment.

template<class OtherElementType , class OtherExtents , class OtherLayoutPolicy , class OtherAccessor >
constexpr	basic_mdspan (const basic_mdspan< OtherElementType, OtherExtents, OtherLayoutPolicy, OtherAccessor > &rhs) noexcept
	Copy constructor.

template<class OtherElementType , class OtherExtents , class OtherLayoutPolicy , class OtherAccessor >
basic_mdspan &	operator= (const basic_mdspan< OtherElementType, OtherExtents, OtherLayoutPolicy, OtherAccessor > &rhs) noexcept
	Copy assignment constructor.

template<class... IndexType>
constexpr	basic_mdspan (pointer ptr, IndexType...DynamicExtents) noexcept
	Construct mdspan by setting the dynamic extents and pointer to data. More...

constexpr	basic_mdspan (pointer ptr, const std::array< ptrdiff_t, extents_type::rank_dynamic()> &dynamic_extents)
	Construct from array describing dynamic extents. More...

constexpr	basic_mdspan (pointer ptr, const mapping_type &m) noexcept
	Construct from pointer and mapping. More...

constexpr	basic_mdspan (pointer ptr, const mapping_type &m, const accessor_type &a) noexcept
	Construct with pointer, mapping and accessor. More...

template<typename U , typename = std::enable_if_t<std::is_same_v<typename std::remove_reference_t<U>::view_type::element_type, ElementType>>>
constexpr	basic_mdspan (U &&other)
	Construct mdspan from multidimensional arrays implemented with mdspan. More...

template<typename U , typename = std::enable_if_t<std::is_same_v<typename std::remove_reference_t<U>::const_view_type::element_type, ElementType>>>
constexpr	basic_mdspan (const U &other)
	Construct mdspan of const Elements from multidimensional arrays implemented with mdspan. More...

template<class... IndexType>
constexpr std::enable_if_t < sizeof...(IndexType)==extents_type::rank(), reference >	operator() (IndexType...indices) const noexcept
	Brace operator to access multidimensional array element. More...

template<class IndexType >
constexpr std::enable_if_t < std::is_integral_v < IndexType > &&extents_type::rank()==1, reference >	operator[] (const IndexType &i) const noexcept
	Canonical bracket operator for one-dimensional arrays. Allows mdspan to act like array in one-dimension. Enabled only when rank==1. More...

template<class IndexType , typename sliced_mdspan_type = basic_mdspan<element_type, decltype(extents_type().sliced_extents()), LayoutPolicy, AccessorPolicy>>
constexpr std::enable_if_t < std::is_integral_v < IndexType > &&(extents_type::rank() > 1)&&std::is_same_v < LayoutPolicy, layout_right > , sliced_mdspan_type >	operator[] (const IndexType index) const noexcept
	Bracket operator for multi-dimensional arrays. More...

constexpr index_type	static_extent (size_t k) const noexcept
	Return the static extent. More...

constexpr index_type	extent (int k) const noexcept
	Return the extent. More...

constexpr const extents_type &	extents () const noexcept
	Return all extents.

constexpr bool	is_unique () const noexcept
	Report if the currently applied map is unique.

constexpr bool	is_strided () const noexcept
	Report if the currently applied map is strided.

constexpr bool	is_contiguous () const noexcept
	Report if the currently applied map is contiguous.

constexpr index_type	stride (size_t r) const noexcept
	Report stride along a specific rank.

constexpr mapping_type	mapping () const noexcept
	Return the currently applied mapping.

constexpr accessor_type	accessor () const noexcept
	Return the memory access model.

constexpr pointer	data () const noexcept
	Return pointer to underlying data.

Static Public Member Functions
static constexpr int	rank () noexcept
	Report the rank.

static constexpr int	rank_dynamic () noexcept
	Report the dynamic rank.

static constexpr bool	is_always_unique () noexcept
	Report if mappings for this basic_span is always unique.

static constexpr bool	is_always_strided () noexcept
	Report if mapping for this basic_span is always strided.

static constexpr bool	is_always_contiguous () noexcept
	Report if mapping for this basic_span is always is_contiguous.

Constructor & Destructor Documentation

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

template<class... IndexType>

constexpr gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::basic_mdspan	(	pointer	ptr,
		IndexType...	DynamicExtents
	)

inlineexplicitnoexcept

Construct mdspan by setting the dynamic extents and pointer to data.

Parameters

[in]	ptr	Pointer to data to be accessed by this span
[in]	DynamicExtents

Template Parameters

IndexType index type to describe dynamic extents

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

constexpr gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::basic_mdspan	(	pointer	ptr,
		const std::array< ptrdiff_t, extents_type::rank_dynamic()> &	dynamic_extents
	)

inline

Construct from array describing dynamic extents.

Parameters

[in]	ptr	Pointer to data to be accessed by this span
[in]	dynamic_extents	Array the size of dynamic extents.

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

constexpr gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::basic_mdspan	(	pointer	ptr,
		const mapping_type &	m
	)

inlinenoexcept

Construct from pointer and mapping.

Parameters

[in]	ptr	Pointer to data to be accessed by this span
[in]	m	Mapping from multidimenisonal indices to one-dimensional offset.

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

constexpr gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::basic_mdspan	(	pointer	ptr,
		const mapping_type &	m,
		const accessor_type &	a
	)

inlinenoexcept

Construct with pointer, mapping and accessor.

Parameters

[in]	ptr	Pointer to data to be accessed by this span
[in]	m	Mapping from multidimenisonal indices to one-dimensional offset.
[in]	a	Accessor implementing memory access model.

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

template<typename U , typename = std::enable_if_t<std::is_same_v<typename std::remove_reference_t<U>::view_type::element_type, ElementType>>>

constexpr gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::basic_mdspan ( U && other )

inline

Construct mdspan from multidimensional arrays implemented with mdspan.

Requires the container to have a view_type describing the mdspan, which is accessible through an asView() call

This allows functions to declare mdspans as arguments, but take e.g. multidimensional arrays implicitly during the function call

Template Parameters

U	container type

Parameters

[in] other mdspan-implementing container

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

template<typename U , typename = std::enable_if_t<std::is_same_v<typename std::remove_reference_t<U>::const_view_type::element_type, ElementType>>>

constexpr gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::basic_mdspan ( const U & other )

inline

Construct mdspan of const Elements from multidimensional arrays implemented with mdspan.

Requires the container to have a const_view_type describing the mdspan, which is accessible through an asConstView() call

This allows functions to declare mdspans as arguments, but take e.g. multidimensional arrays implicitly during the function call

Template Parameters

U	container type

Parameters

[in] other mdspan-implementing container

Member Function Documentation

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

constexpr index_type gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::extent ( int k ) const

inlinenoexcept

Return the extent.

Parameters

[in] k dimension to query for extent

Returns: extent along specified dimension

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

template<class... IndexType>

constexpr std::enable_if_t<sizeof...(IndexType) == extents_type::rank(), reference> gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::operator() ( IndexType... indices ) const

inlinenoexcept

Brace operator to access multidimensional array element.

Parameters

[in] indices The multidimensional indices of the object. Requires rank() == sizeof...(IndexType). Slicing is implemented via sub_span.

Returns: reference to element at indices.

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

template<class IndexType >

constexpr std::enable_if_t<std::is_integral_v<IndexType> && extents_type::rank() == 1, reference> gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::operator[] ( const IndexType & i ) const

inlinenoexcept

Canonical bracket operator for one-dimensional arrays. Allows mdspan to act like array in one-dimension. Enabled only when rank==1.

Parameters

[in] i one-dimensional index

Returns: reference to element stored at position i

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

template<class IndexType , typename sliced_mdspan_type = basic_mdspan<element_type, decltype(extents_type().sliced_extents()), LayoutPolicy, AccessorPolicy>>

constexpr std::enable_if_t<std::is_integral_v<IndexType> && (extents_type::rank() > 1) && std::is_same_v<LayoutPolicy, layout_right>, sliced_mdspan_type> gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::operator[] ( const IndexType index ) const

inlinenoexcept

Bracket operator for multi-dimensional arrays.

Note: Prefer operator() for better compile-time and run-time performance

Slices two- and higher-dimensional arrays along a given slice by returning a new basic_mdspan that drops the first extent and indexes the remaining extents

Note: Currently only implemented for layout_right; For layout_right this implementation has significant performance benefits over implementing a more general slicing operator with a strided layout; Enabled only when rank() > 1

Template Parameters

IndexType integral tyoe for the index that enables indexing with, e.g., int or size_t

Parameters

[in] index one-dimensional index of the slice to be indexed

Returns: basic_mdspan that is sliced at the given index

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>

constexpr index_type gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >::static_extent ( size_t k ) const

inlinenoexcept

Return the static extent.

Parameters

[in] k dimension to query for static extent

Returns: static extent along specified dimension

The documentation for this class was generated from the following file:

src/gromacs/mdspan/mdspan.h

Description

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>> class gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >

Public Types

Public Member Functions

Static Public Member Functions

Constructor & Destructor Documentation

Member Function Documentation

template<class ElementType, class Extents, class LayoutPolicy = layout_right, class AccessorPolicy = accessor_basic<ElementType>>
class gmx::basic_mdspan< ElementType, Extents, LayoutPolicy, AccessorPolicy >