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extents.hpp
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extents.hpp
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//@HEADER
// ************************************************************************
//
// Kokkos v. 4.0
// Copyright (2022) National Technology & Engineering
// Solutions of Sandia, LLC (NTESS).
//
// Under the terms of Contract DE-NA0003525 with NTESS,
// the U.S. Government retains certain rights in this software.
//
// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
// See https://kokkos.org/LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//@HEADER
#pragma once
#include "dynamic_extent.hpp"
#ifdef __cpp_lib_span
#include <span>
#endif
#include <array>
#include <cinttypes>
namespace MDSPAN_IMPL_STANDARD_NAMESPACE {
namespace detail {
// Function used to check compatibility of extents in converting constructor
// can't be a private member function for some reason.
template <size_t... Extents, size_t... OtherExtents>
static constexpr std::integral_constant<bool, false> __check_compatible_extents(
std::integral_constant<bool, false>,
std::integer_sequence<size_t, Extents...>,
std::integer_sequence<size_t, OtherExtents...>) noexcept {
return {};
}
// This helper prevents ICE's on MSVC.
template <size_t Lhs, size_t Rhs>
struct __compare_extent_compatible : std::integral_constant<bool,
Lhs == dynamic_extent ||
Rhs == dynamic_extent ||
Lhs == Rhs>
{};
template <size_t... Extents, size_t... OtherExtents>
static constexpr std::integral_constant<
bool, _MDSPAN_FOLD_AND(__compare_extent_compatible<Extents, OtherExtents>::value)>
__check_compatible_extents(
std::integral_constant<bool, true>,
std::integer_sequence<size_t, Extents...>,
std::integer_sequence<size_t, OtherExtents...>) noexcept {
return {};
}
template<class IndexType, class ... Arguments>
MDSPAN_INLINE_FUNCTION
static constexpr bool are_valid_indices() {
return
(std::is_convertible<Arguments, IndexType>::value && ... && true) &&
(std::is_nothrow_constructible<IndexType, Arguments>::value && ... && true);
}
// ------------------------------------------------------------------
// ------------ static_array ----------------------------------------
// ------------------------------------------------------------------
// array like class which provides an array of static values with get
// function and operator [].
// Implementation of Static Array with recursive implementation of get.
template <size_t R, class T, T... Extents> struct static_array_impl;
template <size_t R, class T, T FirstExt, T... Extents>
struct static_array_impl<R, T, FirstExt, Extents...> {
MDSPAN_INLINE_FUNCTION
constexpr static T get(size_t r) {
if (r == R)
return FirstExt;
else
return static_array_impl<R + 1, T, Extents...>::get(r);
}
template <size_t r> MDSPAN_INLINE_FUNCTION constexpr static T get() {
#if MDSPAN_HAS_CXX_17
if constexpr (r == R)
return FirstExt;
else
return static_array_impl<R + 1, T, Extents...>::template get<r>();
#else
get(r);
#endif
}
};
// End the recursion
template <size_t R, class T, T FirstExt>
struct static_array_impl<R, T, FirstExt> {
MDSPAN_INLINE_FUNCTION
constexpr static T get(size_t) { return FirstExt; }
template <size_t> MDSPAN_INLINE_FUNCTION constexpr static T get() {
return FirstExt;
}
};
// Don't start recursion if size 0
template <class T> struct static_array_impl<0, T> {
MDSPAN_INLINE_FUNCTION
constexpr static T get(size_t) { return T(); }
template <size_t> MDSPAN_INLINE_FUNCTION constexpr static T get() {
return T();
}
};
// Static array, provides get<r>(), get(r) and operator[r]
template <class T, T... Values> struct static_array:
public static_array_impl<0, T, Values...> {
public:
using value_type = T;
MDSPAN_INLINE_FUNCTION
constexpr static size_t size() { return sizeof...(Values); }
};
// ------------------------------------------------------------------
// ------------ index_sequence_scan ---------------------------------
// ------------------------------------------------------------------
// index_sequence_scan takes compile time values and provides get(r)
// and get<r>() which return the sum of the first r-1 values.
// Recursive implementation for get
template <size_t R, size_t... Values> struct index_sequence_scan_impl;
template <size_t R, size_t FirstVal, size_t... Values>
struct index_sequence_scan_impl<R, FirstVal, Values...> {
MDSPAN_INLINE_FUNCTION
constexpr static size_t get(size_t r) {
if (r > R)
return FirstVal + index_sequence_scan_impl<R + 1, Values...>::get(r);
else
return 0;
}
};
template <size_t R, size_t FirstVal>
struct index_sequence_scan_impl<R, FirstVal> {
#if defined(__NVCC__) || defined(__NVCOMPILER) || \
defined(_MDSPAN_COMPILER_INTEL)
// NVCC warns about pointless comparison with 0 for R==0 and r being const
// evaluatable and also 0.
MDSPAN_INLINE_FUNCTION
constexpr static size_t get(size_t r) {
return static_cast<int64_t>(R) > static_cast<int64_t>(r) ? FirstVal : 0;
}
#else
MDSPAN_INLINE_FUNCTION
constexpr static size_t get(size_t r) { return R > r ? FirstVal : 0; }
#endif
};
template <> struct index_sequence_scan_impl<0> {
MDSPAN_INLINE_FUNCTION
constexpr static size_t get(size_t) { return 0; }
};
// ------------------------------------------------------------------
// ------------ possibly_empty_array -------------------------------
// ------------------------------------------------------------------
// array like class which provides get function and operator [], and
// has a specialization for the size 0 case.
// This is needed to make the maybe_static_array be truly empty, for
// all static values.
template <class T, size_t N> struct possibly_empty_array {
T vals[N]{};
MDSPAN_INLINE_FUNCTION
constexpr T &operator[](size_t r) { return vals[r]; }
MDSPAN_INLINE_FUNCTION
constexpr const T &operator[](size_t r) const { return vals[r]; }
};
template <class T> struct possibly_empty_array<T, 0> {
MDSPAN_INLINE_FUNCTION
constexpr T operator[](size_t) { return T(); }
MDSPAN_INLINE_FUNCTION
constexpr const T operator[](size_t) const { return T(); }
};
// ------------------------------------------------------------------
// ------------ maybe_static_array ----------------------------------
// ------------------------------------------------------------------
// array like class which has a mix of static and runtime values but
// only stores the runtime values.
// The type of the static and the runtime values can be different.
// The position of a dynamic value is indicated through a tag value.
template <class TDynamic, class TStatic, TStatic dyn_tag, TStatic... Values>
struct maybe_static_array {
static_assert(std::is_convertible<TStatic, TDynamic>::value, "maybe_static_array: TStatic must be convertible to TDynamic");
static_assert(std::is_convertible<TDynamic, TStatic>::value, "maybe_static_array: TDynamic must be convertible to TStatic");
private:
// Static values member
using static_vals_t = static_array<TStatic, Values...>;
constexpr static size_t m_size = sizeof...(Values);
constexpr static size_t m_size_dynamic =
_MDSPAN_FOLD_PLUS_RIGHT((Values == dyn_tag), 0);
// Dynamic values member
_MDSPAN_NO_UNIQUE_ADDRESS possibly_empty_array<TDynamic, m_size_dynamic>
m_dyn_vals;
// static mapping of indices to the position in the dynamic values array
using dyn_map_t = index_sequence_scan_impl<0, static_cast<size_t>(Values == dyn_tag)...>;
public:
// two types for static and dynamic values
using value_type = TDynamic;
using static_value_type = TStatic;
// tag value indicating dynamic value
constexpr static static_value_type tag_value = dyn_tag;
constexpr maybe_static_array() = default;
// constructor for all static values
// TODO: add precondition check?
MDSPAN_TEMPLATE_REQUIRES(class... Vals,
/* requires */ ((m_size_dynamic == 0) &&
(sizeof...(Vals) > 0)))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(Vals...) : m_dyn_vals{} {}
// constructors from dynamic values only
MDSPAN_TEMPLATE_REQUIRES(class... DynVals,
/* requires */ (sizeof...(DynVals) ==
m_size_dynamic &&
m_size_dynamic > 0))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(DynVals... vals)
: m_dyn_vals{static_cast<TDynamic>(vals)...} {}
MDSPAN_TEMPLATE_REQUIRES(class T, size_t N,
/* requires */ (N == m_size_dynamic && N > 0))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(const std::array<T, N> &vals) {
for (size_t r = 0; r < N; r++)
m_dyn_vals[r] = static_cast<TDynamic>(vals[r]);
}
MDSPAN_TEMPLATE_REQUIRES(class T, size_t N,
/* requires */ (N == m_size_dynamic && N == 0))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(const std::array<T, N> &) : m_dyn_vals{} {}
#ifdef __cpp_lib_span
MDSPAN_TEMPLATE_REQUIRES(class T, size_t N,
/* requires */ (N == m_size_dynamic && N > 0))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(const std::span<T, N> &vals) {
for (size_t r = 0; r < N; r++)
m_dyn_vals[r] = static_cast<TDynamic>(vals[r]);
}
MDSPAN_TEMPLATE_REQUIRES(class T, size_t N,
/* requires */ (N == m_size_dynamic && N == 0))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(const std::span<T, N> &) : m_dyn_vals{} {}
#endif
// constructors from all values
MDSPAN_TEMPLATE_REQUIRES(class... DynVals,
/* requires */ (sizeof...(DynVals) !=
m_size_dynamic &&
m_size_dynamic > 0))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(DynVals... vals)
: m_dyn_vals{} {
static_assert((sizeof...(DynVals) == m_size), "Invalid number of values.");
TDynamic values[m_size]{static_cast<TDynamic>(vals)...};
for (size_t r = 0; r < m_size; r++) {
TStatic static_val = static_vals_t::get(r);
if (static_val == dyn_tag) {
m_dyn_vals[dyn_map_t::get(r)] = values[r];
}
// Precondition check
#ifdef _MDSPAN_DEBUG
else {
assert(values[r] == static_cast<TDynamic>(static_val));
}
#endif
}
}
MDSPAN_TEMPLATE_REQUIRES(
class T, size_t N,
/* requires */ (N != m_size_dynamic && m_size_dynamic > 0))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(const std::array<T, N> &vals) {
static_assert((N == m_size), "Invalid number of values.");
// Precondition check
#ifdef _MDSPAN_DEBUG
assert(N == m_size);
#endif
for (size_t r = 0; r < m_size; r++) {
TStatic static_val = static_vals_t::get(r);
if (static_val == dyn_tag) {
m_dyn_vals[dyn_map_t::get(r)] = static_cast<TDynamic>(vals[r]);
}
// Precondition check
#ifdef _MDSPAN_DEBUG
else {
assert(static_cast<TDynamic>(vals[r]) ==
static_cast<TDynamic>(static_val));
}
#endif
}
}
#ifdef __cpp_lib_span
MDSPAN_TEMPLATE_REQUIRES(
class T, size_t N,
/* requires */ (N != m_size_dynamic && m_size_dynamic > 0))
MDSPAN_INLINE_FUNCTION
constexpr maybe_static_array(const std::span<T, N> &vals) {
static_assert((N == m_size) || (m_size == dynamic_extent));
#ifdef _MDSPAN_DEBUG
assert(N == m_size);
#endif
for (size_t r = 0; r < m_size; r++) {
TStatic static_val = static_vals_t::get(r);
if (static_val == dyn_tag) {
m_dyn_vals[dyn_map_t::get(r)] = static_cast<TDynamic>(vals[r]);
}
#ifdef _MDSPAN_DEBUG
else {
assert(static_cast<TDynamic>(vals[r]) ==
static_cast<TDynamic>(static_val));
}
#endif
}
}
#endif
// access functions
MDSPAN_INLINE_FUNCTION
constexpr static TStatic static_value(size_t r) { return static_vals_t::get(r); }
MDSPAN_INLINE_FUNCTION
constexpr TDynamic value(size_t r) const {
TStatic static_val = static_vals_t::get(r);
return static_val == dyn_tag ? m_dyn_vals[dyn_map_t::get(r)]
: static_cast<TDynamic>(static_val);
}
MDSPAN_INLINE_FUNCTION
constexpr TDynamic operator[](size_t r) const { return value(r); }
// observers
MDSPAN_INLINE_FUNCTION
constexpr static size_t size() { return m_size; }
MDSPAN_INLINE_FUNCTION
constexpr static size_t size_dynamic() { return m_size_dynamic; }
};
} // namespace detail
} // namespace MDSPAN_IMPL_STANDARD_NAMESPACE
namespace MDSPAN_IMPL_STANDARD_NAMESPACE {
// ------------------------------------------------------------------
// ------------ extents ---------------------------------------------
// ------------------------------------------------------------------
// Class to describe the extents of a multi dimensional array.
// Used by mdspan, mdarray and layout mappings.
// See ISO C++ standard [mdspan.extents]
template <class IndexType, size_t... Extents> class extents {
public:
// typedefs for integral types used
using index_type = IndexType;
using size_type = std::make_unsigned_t<index_type>;
using rank_type = size_t;
static_assert(std::is_integral<index_type>::value && !std::is_same<index_type, bool>::value,
MDSPAN_IMPL_STANDARD_NAMESPACE_STRING "::extents::index_type must be a signed or unsigned integer type");
private:
constexpr static rank_type m_rank = sizeof...(Extents);
constexpr static rank_type m_rank_dynamic =
_MDSPAN_FOLD_PLUS_RIGHT((Extents == dynamic_extent), /* + ... + */ 0);
// internal storage type using maybe_static_array
using vals_t =
detail::maybe_static_array<IndexType, size_t, dynamic_extent, Extents...>;
_MDSPAN_NO_UNIQUE_ADDRESS vals_t m_vals;
public:
// [mdspan.extents.obs], observers of multidimensional index space
MDSPAN_INLINE_FUNCTION
constexpr static rank_type rank() noexcept { return m_rank; }
MDSPAN_INLINE_FUNCTION
constexpr static rank_type rank_dynamic() noexcept { return m_rank_dynamic; }
MDSPAN_INLINE_FUNCTION
constexpr index_type extent(rank_type r) const noexcept { return m_vals.value(r); }
MDSPAN_INLINE_FUNCTION
constexpr static size_t static_extent(rank_type r) noexcept {
return vals_t::static_value(r);
}
// [mdspan.extents.cons], constructors
MDSPAN_INLINE_FUNCTION_DEFAULTED
constexpr extents() noexcept = default;
// Construction from just dynamic or all values.
// Precondition check is deferred to maybe_static_array constructor
MDSPAN_TEMPLATE_REQUIRES(
class... OtherIndexTypes,
/* requires */ (
_MDSPAN_FOLD_AND(_MDSPAN_TRAIT(std::is_convertible, OtherIndexTypes,
index_type) /* && ... */) &&
_MDSPAN_FOLD_AND(_MDSPAN_TRAIT(std::is_nothrow_constructible, index_type,
OtherIndexTypes) /* && ... */) &&
(sizeof...(OtherIndexTypes) == m_rank ||
sizeof...(OtherIndexTypes) == m_rank_dynamic)))
MDSPAN_INLINE_FUNCTION
constexpr explicit extents(OtherIndexTypes... dynvals) noexcept
: m_vals(static_cast<index_type>(dynvals)...) {}
MDSPAN_TEMPLATE_REQUIRES(
class OtherIndexType, size_t N,
/* requires */
(
_MDSPAN_TRAIT(std::is_convertible, const OtherIndexType&, index_type) &&
_MDSPAN_TRAIT(std::is_nothrow_constructible, index_type,
const OtherIndexType&) &&
(N == m_rank || N == m_rank_dynamic)))
MDSPAN_INLINE_FUNCTION
MDSPAN_CONDITIONAL_EXPLICIT(N != m_rank_dynamic)
constexpr extents(const std::array<OtherIndexType, N> &exts) noexcept
: m_vals(std::move(exts)) {}
#ifdef __cpp_lib_span
MDSPAN_TEMPLATE_REQUIRES(
class OtherIndexType, size_t N,
/* requires */
(_MDSPAN_TRAIT(std::is_convertible, const OtherIndexType&, index_type) &&
_MDSPAN_TRAIT(std::is_nothrow_constructible, index_type, const OtherIndexType&) &&
(N == m_rank || N == m_rank_dynamic)))
MDSPAN_INLINE_FUNCTION
MDSPAN_CONDITIONAL_EXPLICIT(N != m_rank_dynamic)
constexpr extents(const std::span<OtherIndexType, N> &exts) noexcept
: m_vals(std::move(exts)) {}
#endif
private:
// Function to construct extents storage from other extents.
// With C++ 17 the first two variants could be collapsed using if constexpr
// in which case you don't need all the requires clauses.
// in C++ 14 mode that doesn't work due to infinite recursion
MDSPAN_TEMPLATE_REQUIRES(
size_t DynCount, size_t R, class OtherExtents, class... DynamicValues,
/* requires */ ((R < m_rank) && (static_extent(R) == dynamic_extent)))
MDSPAN_INLINE_FUNCTION
constexpr
vals_t __construct_vals_from_extents(std::integral_constant<size_t, DynCount>,
std::integral_constant<size_t, R>,
const OtherExtents &exts,
DynamicValues... dynamic_values) noexcept {
return __construct_vals_from_extents(
std::integral_constant<size_t, DynCount + 1>(),
std::integral_constant<size_t, R + 1>(), exts, dynamic_values...,
exts.extent(R));
}
MDSPAN_TEMPLATE_REQUIRES(
size_t DynCount, size_t R, class OtherExtents, class... DynamicValues,
/* requires */ ((R < m_rank) && (static_extent(R) != dynamic_extent)))
MDSPAN_INLINE_FUNCTION
constexpr
vals_t __construct_vals_from_extents(std::integral_constant<size_t, DynCount>,
std::integral_constant<size_t, R>,
const OtherExtents &exts,
DynamicValues... dynamic_values) noexcept {
return __construct_vals_from_extents(
std::integral_constant<size_t, DynCount>(),
std::integral_constant<size_t, R + 1>(), exts, dynamic_values...);
}
MDSPAN_TEMPLATE_REQUIRES(
size_t DynCount, size_t R, class OtherExtents, class... DynamicValues,
/* requires */ ((R == m_rank) && (DynCount == m_rank_dynamic)))
MDSPAN_INLINE_FUNCTION
constexpr
vals_t __construct_vals_from_extents(std::integral_constant<size_t, DynCount>,
std::integral_constant<size_t, R>,
const OtherExtents &,
DynamicValues... dynamic_values) noexcept {
return vals_t{static_cast<index_type>(dynamic_values)...};
}
public:
// Converting constructor from other extents specializations
MDSPAN_TEMPLATE_REQUIRES(
class OtherIndexType, size_t... OtherExtents,
/* requires */
(
/* multi-stage check to protect from invalid pack expansion when sizes
don't match? */
decltype(detail::__check_compatible_extents(
// using: sizeof...(Extents) == sizeof...(OtherExtents) as the second argument fails with MSVC+NVCC with some obscure expansion error
// MSVC: 19.38.33133 NVCC: 12.0
std::integral_constant<bool, extents<int, Extents...>::rank() == extents<int, OtherExtents...>::rank()>{},
std::integer_sequence<size_t, Extents...>{},
std::integer_sequence<size_t, OtherExtents...>{}))::value
)
)
MDSPAN_INLINE_FUNCTION
MDSPAN_CONDITIONAL_EXPLICIT((((Extents != dynamic_extent) &&
(OtherExtents == dynamic_extent)) ||
...) ||
(std::numeric_limits<index_type>::max() <
std::numeric_limits<OtherIndexType>::max()))
constexpr extents(const extents<OtherIndexType, OtherExtents...> &other) noexcept
: m_vals(__construct_vals_from_extents(
std::integral_constant<size_t, 0>(),
std::integral_constant<size_t, 0>(), other)) {}
// Comparison operator
template <class OtherIndexType, size_t... OtherExtents>
MDSPAN_INLINE_FUNCTION friend constexpr bool
operator==(const extents &lhs,
const extents<OtherIndexType, OtherExtents...> &rhs) noexcept {
if constexpr (rank() != extents<OtherIndexType, OtherExtents...>::rank()) {
return false;
} else {
using common_t = std::common_type_t<index_type, OtherIndexType>;
for (size_type r = 0; r < m_rank; r++)
if(static_cast<common_t>(rhs.extent(r)) != static_cast<common_t>(lhs.extent(r))) return false;
}
return true;
}
#if !(MDSPAN_HAS_CXX_20)
template <class OtherIndexType, size_t... OtherExtents>
MDSPAN_INLINE_FUNCTION friend constexpr bool
operator!=(extents const &lhs,
extents<OtherIndexType, OtherExtents...> const &rhs) noexcept {
return !(lhs == rhs);
}
#endif
};
// Recursive helper classes to implement dextents alias for extents
namespace detail {
template <class IndexType, size_t Rank,
class Extents = ::MDSPAN_IMPL_STANDARD_NAMESPACE::extents<IndexType>>
struct __make_dextents;
template <class IndexType, size_t Rank, size_t... ExtentsPack>
struct __make_dextents<
IndexType, Rank, ::MDSPAN_IMPL_STANDARD_NAMESPACE::extents<IndexType, ExtentsPack...>>
{
using type = typename __make_dextents<
IndexType, Rank - 1,
::MDSPAN_IMPL_STANDARD_NAMESPACE::extents<IndexType,
::MDSPAN_IMPL_STANDARD_NAMESPACE::dynamic_extent,
ExtentsPack...>>::type;
};
template <class IndexType, size_t... ExtentsPack>
struct __make_dextents<
IndexType, 0, ::MDSPAN_IMPL_STANDARD_NAMESPACE::extents<IndexType, ExtentsPack...>>
{
using type = ::MDSPAN_IMPL_STANDARD_NAMESPACE::extents<IndexType, ExtentsPack...>;
};
} // end namespace detail
// [mdspan.extents.dextents], alias template
template <class IndexType, size_t Rank>
using dextents = typename detail::__make_dextents<IndexType, Rank>::type;
// Deduction guide for extents
#if defined(_MDSPAN_USE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION)
template <class... IndexTypes>
extents(IndexTypes...)
-> extents<size_t,
((void) sizeof(IndexTypes), ::MDSPAN_IMPL_STANDARD_NAMESPACE::dynamic_extent)...>;
#endif
// Helper type traits for identifying a class as extents.
namespace detail {
template <class T> struct __is_extents : ::std::false_type {};
template <class IndexType, size_t... ExtentsPack>
struct __is_extents<::MDSPAN_IMPL_STANDARD_NAMESPACE::extents<IndexType, ExtentsPack...>>
: ::std::true_type {};
template <class T>
#if MDSPAN_HAS_CXX_17
inline
#else
static
#endif
constexpr bool __is_extents_v = __is_extents<T>::value;
} // namespace detail
} // namespace MDSPAN_IMPL_STANDARD_NAMESPACE