arene::base::layout_stride::mapping< Extents > Class Template Reference

A mapping from a logical pack of indices into a single flat physical output index, using a strided algorithm. More...

Inheritance diagram for arene::base::layout_stride::mapping< Extents >:

Public Types
using	layout_type = layout_stride
	The tag type of the layout used by this mapping.

Public Member Functions
constexpr	mapping () noexcept
	Construct a default strided mapping for the given extents, which has the same layout as layout_right.
constexpr	mapping (extents_type const &exts, array< index_type, extents_type::rank()> const &strds, layout_detail::check_bypasser) noexcept
	Construct a mapping with the given strides, bypassing precondition checks.
template<class OtherIndexType, constraints< std::enable_if_t< std::is_convertible< OtherIndexType const &, index_type >::value >, std::enable_if_t< std::is_nothrow_constructible< index_type, OtherIndexType const & >::value > > = nullptr>
constexpr	mapping (extents_type const &exts, array< OtherIndexType, extents_type::rank()> const &strds) noexcept
	Construct a mapping with the given strides; they must be valid for a default-constructed extents_type.
template<class OtherIndexType, constraints< std::enable_if_t< std::is_convertible< OtherIndexType const &, index_type >::value >, std::enable_if_t< std::is_nothrow_constructible< index_type, OtherIndexType const & >::value > > = nullptr>
constexpr	mapping (extents_type const &exts, span< OtherIndexType, extents_type::rank()> strds) noexcept
	Construct a mapping with the given strides; they must be valid for a default-constructed extents_type.
template<class StridedLayoutMapping, constraints< std::enable_if_t< is_layout_mapping_v< StridedLayoutMapping > >, std::enable_if_t< std::is_constructible< extents_type, typename StridedLayoutMapping::extents_type >::value >, std::enable_if_t< StridedLayoutMapping::is_always_strided()>, std::enable_if_t< StridedLayoutMapping::is_always_unique()>, std::enable_if_t< layout_detail::implicit_conversion_ok< StridedLayoutMapping, mapping >::value > > = nullptr>
constexpr	mapping (StridedLayoutMapping const &other) noexcept
	Construct a mapping from another strided mapping; implicit for certain known-safe mapping types.
template<class StridedLayoutMapping, constraints< std::enable_if_t< is_layout_mapping_v< StridedLayoutMapping > >, std::enable_if_t< std::is_constructible< extents_type, typename StridedLayoutMapping::extents_type >::value >, std::enable_if_t< StridedLayoutMapping::is_always_strided()>, std::enable_if_t< StridedLayoutMapping::is_always_unique()>, std::enable_if_t<!layout_detail::implicit_conversion_ok< StridedLayoutMapping, mapping >::value > > = nullptr>
constexpr	mapping (StridedLayoutMapping const &other) noexcept
	Construct a mapping from another strided mapping; implicit for certain known-safe mapping types.
constexpr auto	is_exhaustive () const noexcept -> bool
	Return whether or not this instance is exhaustive, i.e. every element is reachable using some indices.

Static Public Member Functions
static constexpr auto	is_always_exhaustive () noexcept -> bool
	Return whether or not this mapping is always exhaustive, i.e. every element is reachable using some indices.

Friends
template<class Left, constraints< std::enable_if_t<!std::is_same< typename Left::layout_type, layout_stride >::value >, std::enable_if_t< is_layout_mapping_v< Left > >, std::enable_if_t< Left::extents_type::rank()==extents_type::rank()>, std::enable_if_t< Left::is_always_strided()> > = nullptr>
constexpr auto	operator!= (Left const &left, mapping const &right) noexcept -> bool
	Compare two strided mappings for inequality, of which at least one must be a layout_stride::mapping.
template<class Right, constraints< std::enable_if_t< is_layout_mapping_v< Right > >, std::enable_if_t< Right::extents_type::rank()==extents_type::rank()>, std::enable_if_t< Right::is_always_strided()> > = nullptr>
constexpr auto	operator!= (mapping const &left, Right const &right) noexcept -> bool
	Compare two strided mappings for inequality, of which at least one must be a layout_stride::mapping.
template<class Left, constraints< std::enable_if_t<!std::is_same< typename Left::layout_type, layout_stride >::value >, std::enable_if_t< is_layout_mapping_v< Left > >, std::enable_if_t< Left::extents_type::rank()==extents_type::rank()>, std::enable_if_t< Left::is_always_strided()> > = nullptr>
constexpr auto	operator== (Left const &left, mapping const &right) noexcept -> bool
	Compare two strided mappings for equality, of which at least one must be a layout_stride::mapping.
template<class Right, constraints< std::enable_if_t< is_layout_mapping_v< Right > >, std::enable_if_t< Right::extents_type::rank()==extents_type::rank()>, std::enable_if_t< Right::is_always_strided()> > = nullptr>
constexpr auto	operator== (mapping const &left, Right const &right) noexcept -> bool
	Compare two strided mappings for equality, of which at least one must be a layout_stride::mapping.
template<class SrcMapping, class... CanonicalSliceSpecifiers, constraints< std::enable_if_t< sizeof...(CanonicalSliceSpecifiers)==extents_type::rank()>, std::enable_if_t< mdspan_detail::all_valid_submdspan_slice_types_for_v< extents_type, CanonicalSliceSpecifiers... > > > = nullptr>
constexpr auto	submdspan_mapping (SrcMapping const &src, CanonicalSliceSpecifiers... slices) noexcept -> submdspan_mapping_result< layout_stride::mapping< submdspan_subextents_type_t< extents_type, CanonicalSliceSpecifiers... > > >
	compute submdspan mapping and offset for a layout_stride mapping

Detailed Description

template<class Extents>
class arene::base::layout_stride::mapping< Extents >

A mapping from a logical pack of indices into a single flat physical output index, using a strided algorithm.

Template Parameters

The	extents of the space used for this mapping; must be a specialization of extents

Member Typedef Documentation

layout_type

template<class Extents>

using arene::base::layout_stride::mapping< Extents >::layout_type = layout_stride

The tag type of the layout used by this mapping.

Constructor & Destructor Documentation

mapping() [1/6]

template<class Extents>

arene::base::layout_stride::mapping< Extents >::mapping ( extents_type const & exts, array< index_type, extents_type::rank()> const & strds, layout_detail::check_bypasser  )

inlineconstexprnoexcept

Construct a mapping with the given strides, bypassing precondition checks.

Note

This can only be called from classes which inherit from layout_stride::mapping. It is used when slicing a layout_stride::mapping if the slice arguments are valid, so that the preconditions on the public constructors need not be re-checked.

Parameters

exts	A set of extents to use for this mapping
strds	A set of strides to use for this mapping

mapping() [2/6]

template<class Extents>

arene::base::layout_stride::mapping< Extents >::mapping ( )

inlineconstexprnoexcept

Construct a default strided mapping for the given extents, which has the same layout as layout_right.

mapping() [3/6]

template<class Extents>

template<class OtherIndexType, constraints< std::enable_if_t< std::is_convertible< OtherIndexType const &, index_type >::value >, std::enable_if_t< std::is_nothrow_constructible< index_type, OtherIndexType const & >::value > > = nullptr>

arene::base::layout_stride::mapping< Extents >::mapping ( extents_type const & exts, span< OtherIndexType, extents_type::rank()> strds )

inlineconstexprnoexcept

Construct a mapping with the given strides; they must be valid for a default-constructed extents_type.

Template Parameters

OtherIndexType

The original index type used by strds; must be convertible to index_type

Parameters

exts	A set of extents to use for this mapping
strds	A set of strides to use for this mapping

Precondition

All strides are positive when converted to index_type

Size of the output index space is representable as index_type

strds defines a unique (one-to-one) mapping from exts

mapping() [4/6]

template<class Extents>

template<class OtherIndexType, constraints< std::enable_if_t< std::is_convertible< OtherIndexType const &, index_type >::value >, std::enable_if_t< std::is_nothrow_constructible< index_type, OtherIndexType const & >::value > > = nullptr>

arene::base::layout_stride::mapping< Extents >::mapping ( extents_type const & exts, array< OtherIndexType, extents_type::rank()> const & strds )

inlineconstexprnoexcept

Construct a mapping with the given strides; they must be valid for a default-constructed extents_type.

Template Parameters

OtherIndexType

The original index type used by strds; must be convertible to index_type

Parameters

exts	A set of extents to use for this mapping
strds	A set of strides to use for this mapping

Precondition

All strides are positive when converted to index_type, else ARENE_PRECONDITION violation

Size of the output index space is representable as index_type, else ARENE_PRECONDITION violation

strds defines a unique (one-to-one) mapping from exts, else ARENE_PRECONDITION violation

mapping() [5/6]

template<class Extents>

template<class StridedLayoutMapping, constraints< std::enable_if_t< is_layout_mapping_v< StridedLayoutMapping > >, std::enable_if_t< std::is_constructible< extents_type, typename StridedLayoutMapping::extents_type >::value >, std::enable_if_t< StridedLayoutMapping::is_always_strided()>, std::enable_if_t< StridedLayoutMapping::is_always_unique()>, std::enable_if_t< layout_detail::implicit_conversion_ok< StridedLayoutMapping, mapping >::value > > = nullptr>

arene::base::layout_stride::mapping< Extents >::mapping ( StridedLayoutMapping const & other )

inlineconstexprnoexcept

Construct a mapping from another strided mapping; implicit for certain known-safe mapping types.

Template Parameters

StridedLayoutMapping

A layout mapping satisfying [mdspan.layout.reqmts] which is always strided and unique

Parameters

other

A mapping to convert

Precondition

All strides are positive when converted to index_type, else ARENE_PRECONDITION violation

Size of the output index space is representable as index_type, else ARENE_PRECONDITION violation

other(0, 0, 0...) == 0, else ARENE_PRECONDITION violation

mapping() [6/6]

template<class Extents>

template<class StridedLayoutMapping, constraints< std::enable_if_t< is_layout_mapping_v< StridedLayoutMapping > >, std::enable_if_t< std::is_constructible< extents_type, typename StridedLayoutMapping::extents_type >::value >, std::enable_if_t< StridedLayoutMapping::is_always_strided()>, std::enable_if_t< StridedLayoutMapping::is_always_unique()>, std::enable_if_t<!layout_detail::implicit_conversion_ok< StridedLayoutMapping, mapping >::value > > = nullptr>

arene::base::layout_stride::mapping< Extents >::mapping ( StridedLayoutMapping const & other )

inlineexplicitconstexprnoexcept

Construct a mapping from another strided mapping; implicit for certain known-safe mapping types.

Template Parameters

StridedLayoutMapping

A layout mapping satisfying [mdspan.layout.reqmts] which is always strided and unique

Parameters

other

A mapping to convert

Precondition

All strides are positive when converted to index_type, else ARENE_PRECONDITION violation

Size of the output index space is representable as index_type, else ARENE_PRECONDITION violation

other(0, 0, 0...) == 0, else ARENE_PRECONDITION violation

Member Function Documentation

is_always_exhaustive()

template<class Extents>

static constexpr auto arene::base::layout_stride::mapping< Extents >::is_always_exhaustive ( ) -> bool

inlinestaticconstexprnoexcept

Return whether or not this mapping is always exhaustive, i.e. every element is reachable using some indices.

Returns

false because it's possible to construct non-exhaustive mappings using this class

Note

In mathematical terms this asks if the mapping is always surjective/onto.

is_exhaustive()

template<class Extents>

auto arene::base::layout_stride::mapping< Extents >::is_exhaustive ( ) const -> bool

inlineconstexprnoexcept

Return whether or not this instance is exhaustive, i.e. every element is reachable using some indices.

Returns

true if every provided stride is the product of the extents corresponding to some subset of the other strides, otherwise false

Note

In mathematical terms this asks if the mapping is surjective/onto.

Friends And Related Symbol Documentation

operator!= [1/2]

template<class Extents>

template<class Left, constraints< std::enable_if_t<!std::is_same< typename Left::layout_type, layout_stride >::value >, std::enable_if_t< is_layout_mapping_v< Left > >, std::enable_if_t< Left::extents_type::rank()==extents_type::rank()>, std::enable_if_t< Left::is_always_strided()> > = nullptr>

auto operator!= ( Left const & left, mapping< Extents > const & right ) -> bool

friend

Compare two strided mappings for inequality, of which at least one must be a layout_stride::mapping.

Template Parameters

Left	The type of the left side of the comparison; must be strided and satisfy is_layout_mapping_v

Parameters

left	An instance of Left
right	An instance of layout_stride::mapping

Returns

true if left and right have different extents or strides, or one doesn't map (0,0,...) to 0

operator!= [2/2]

template<class Extents>

template<class Right, constraints< std::enable_if_t< is_layout_mapping_v< Right > >, std::enable_if_t< Right::extents_type::rank()==extents_type::rank()>, std::enable_if_t< Right::is_always_strided()> > = nullptr>

auto operator!= ( mapping< Extents > const & left, Right const & right ) -> bool

friend

Compare two strided mappings for inequality, of which at least one must be a layout_stride::mapping.

Template Parameters

Right

The type of the right side of the comparison; must be strided and satisfy is_layout_mapping_v

Parameters

left	An instance of layout_stride::mapping
right	An instance of Right

Returns

true if left and right have different extents or strides, or one doesn't map (0,0,...) to 0

operator== [1/2]

template<class Extents>

template<class Left, constraints< std::enable_if_t<!std::is_same< typename Left::layout_type, layout_stride >::value >, std::enable_if_t< is_layout_mapping_v< Left > >, std::enable_if_t< Left::extents_type::rank()==extents_type::rank()>, std::enable_if_t< Left::is_always_strided()> > = nullptr>

auto operator== ( Left const & left, mapping< Extents > const & right ) -> bool

friend

Compare two strided mappings for equality, of which at least one must be a layout_stride::mapping.

Template Parameters

Left	The type of the left side of the comparison; must be strided and satisfy is_layout_mapping_v

Parameters

left	An instance of Left
right	An instance of layout_stride::mapping

Returns

true if left and right have the same extents and strides, and both map (0,0,...) to 0

operator== [2/2]

template<class Extents>

template<class Right, constraints< std::enable_if_t< is_layout_mapping_v< Right > >, std::enable_if_t< Right::extents_type::rank()==extents_type::rank()>, std::enable_if_t< Right::is_always_strided()> > = nullptr>

auto operator== ( mapping< Extents > const & left, Right const & right ) -> bool

friend

Compare two strided mappings for equality, of which at least one must be a layout_stride::mapping.

Template Parameters

Right

The type of the right side of the comparison; must be strided and satisfy is_layout_mapping_v

Parameters

left	An instance of layout_stride::mapping
right	An instance of Right

Returns

true if left and right have the same extents and strides, and both map (0,0,...) to 0

submdspan_mapping

template<class Extents>

template<class SrcMapping, class... CanonicalSliceSpecifiers, constraints< std::enable_if_t< sizeof...(CanonicalSliceSpecifiers)==extents_type::rank()>, std::enable_if_t< mdspan_detail::all_valid_submdspan_slice_types_for_v< extents_type, CanonicalSliceSpecifiers... > > > = nullptr>

auto submdspan_mapping ( SrcMapping const & src, CanonicalSliceSpecifiers... slices ) -> submdspan_mapping_result< layout_stride::mapping<submdspan_subextents_type_t<extents_type, CanonicalSliceSpecifiers...>>>

friend

compute submdspan mapping and offset for a layout_stride mapping

Template Parameters

CanonicalSliceSpecifiers

submdspan slice specifier types

Parameters

src	source layout_stride::mapping to slice
slices	submdspan slice specifiers

Uses slices to compute the sub-extents, sub-strides, and offset of the submdspan. The slices must be in canonical form.

Returns

A submdspan_mapping_result containing the sub-mapping and offset such that indexing the sub-mapping and adding the offset recovers the corresponding index in the original mapping.

Note

Constraints

• sizeof...(CanonicalSliceSpecifiers) == extents_type::rank()
• for each rank index k of src.extents(), CanonicalSliceSpecifiers...[k] is a valid submdspan slice type for the k-th extent of extents_type

Preconditions

• for each rank index k of src.extents(), slices...[k] denotes a valid submdspan slice for the k-th extent of src.extents()

Remarks

• this function is found via argument-dependent lookup as a friend of layout_stride::mapping
• the layout_stride specialization of submdspan_mapping always produces a layout_stride mapping for the submdspan.

---

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

• arene/base/mdspan/layout_stride.hpp