blas1_linalg_add.hpp

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#ifndef LINALG_INCLUDE_EXPERIMENTAL___P1673_BITS_BLAS1_LINALG_ADD_HPP_
#define LINALG_INCLUDE_EXPERIMENTAL___P1673_BITS_BLAS1_LINALG_ADD_HPP_

namespace std {
namespace experimental {
inline namespace __p1673_version_0 {
namespace linalg {

namespace {

template<class ElementType_x,
	 class SizeType_x,
         ::std::size_t ext_x,
         class Layout_x,
         class Accessor_x,
         class ElementType_y,
	 class SizeType_y,
         ::std::size_t ext_y,
         class Layout_y,
         class Accessor_y,
         class ElementType_z,
	 class SizeType_z,
         ::std::size_t ext_z,
         class Layout_z,
         class Accessor_z>
void add_rank_1(
  std::experimental::mdspan<ElementType_x, std::experimental::extents<SizeType_x, ext_x>, Layout_x, Accessor_x> x,
  std::experimental::mdspan<ElementType_y, std::experimental::extents<SizeType_y, ext_y>, Layout_y, Accessor_y> y,
  std::experimental::mdspan<ElementType_z, std::experimental::extents<SizeType_z, ext_z>, Layout_z, Accessor_z> z)
{
  static_assert(x.static_extent(0) == dynamic_extent ||
                z.static_extent(0) == dynamic_extent ||
                x.static_extent(0) == z.static_extent(0));
  static_assert(y.static_extent(0) == dynamic_extent ||
                z.static_extent(0) == dynamic_extent ||
                y.static_extent(0) == z.static_extent(0));
  static_assert(x.static_extent(0) == dynamic_extent ||
                y.static_extent(0) == dynamic_extent ||
                x.static_extent(0) == y.static_extent(0));

  using size_type = std::common_type_t<SizeType_x, SizeType_y, SizeType_z>;
  for (size_type i = 0; i < z.extent(0); ++i) {
    z(i) = x(i) + y(i);
  }
}

template<class ElementType_x,
	 class SizeType_x,
         ::std::size_t numRows_x,
         ::std::size_t numCols_x,
         class Layout_x,
         class Accessor_x,
         class ElementType_y,
	 class SizeType_y,
         ::std::size_t numRows_y,
         ::std::size_t numCols_y,
         class Layout_y,
         class Accessor_y,
         class ElementType_z,
	 class SizeType_z,
         ::std::size_t numRows_z,
         ::std::size_t numCols_z,
         class Layout_z,
         class Accessor_z>
void add_rank_2(
  std::experimental::mdspan<ElementType_x, std::experimental::extents<SizeType_x, numRows_x, numCols_x>, Layout_x, Accessor_x> x,
  std::experimental::mdspan<ElementType_y, std::experimental::extents<SizeType_y, numRows_y, numCols_y>, Layout_y, Accessor_y> y,
  std::experimental::mdspan<ElementType_z, std::experimental::extents<SizeType_z, numRows_z, numCols_z>, Layout_z, Accessor_z> z)
{
  static_assert(x.static_extent(0) == dynamic_extent ||
                z.static_extent(0) == dynamic_extent ||
                x.static_extent(0) == z.static_extent(0));
  static_assert(y.static_extent(0) == dynamic_extent ||
                z.static_extent(0) == dynamic_extent ||
                y.static_extent(0) == z.static_extent(0));
  static_assert(x.static_extent(0) == dynamic_extent ||
                y.static_extent(0) == dynamic_extent ||
                x.static_extent(0) == y.static_extent(0));

  static_assert(x.static_extent(1) == dynamic_extent ||
                z.static_extent(1) == dynamic_extent ||
                x.static_extent(1) == z.static_extent(1));
  static_assert(y.static_extent(1) == dynamic_extent ||
                z.static_extent(1) == dynamic_extent ||
                y.static_extent(1) == z.static_extent(1));
  static_assert(x.static_extent(1) == dynamic_extent ||
                y.static_extent(1) == dynamic_extent ||
                x.static_extent(1) == y.static_extent(1));

  using size_type = std::common_type_t<SizeType_x, SizeType_y, SizeType_z>;
  for (size_type j = 0; j < x.extent(1); ++j) {
    for (size_type i = 0; i < x.extent(0); ++i) {
      z(i,j) = x(i,j) + y(i,j);
    }
  }
}

template <class Exec, class x_t, class y_t, class z_t, class = void>
struct is_custom_add_avail : std::false_type {};

template <class Exec, class x_t, class y_t, class z_t>
struct is_custom_add_avail<
  Exec, x_t, y_t, z_t,
  std::enable_if_t<
    std::is_void_v<
      decltype(add
	       (std::declval<Exec>(),
		std::declval<x_t>(),
		std::declval<y_t>(),
		std::declval<z_t>()
		)
	       )
      >
    && !linalg::impl::is_inline_exec_v<Exec>
    >
  >
  : std::true_type{};

} // end anonymous namespace


MDSPAN_TEMPLATE_REQUIRES(
         class ElementType_x,
	 class SizeType_x,
         ::std::size_t ... ext_x,
         class Layout_x,
         class Accessor_x,
         class ElementType_y,
	 class SizeType_y,
         ::std::size_t ... ext_y,
         class Layout_y,
         class Accessor_y,
         class ElementType_z,
	 class SizeType_z,
         ::std::size_t ... ext_z,
         class Layout_z,
         class Accessor_z,
         /* requires */ (sizeof...(ext_x) == sizeof...(ext_y) && sizeof...(ext_x) == sizeof...(ext_z))
)
void add(
  std::experimental::linalg::impl::inline_exec_t&& /* exec */,
  std::experimental::mdspan<ElementType_x, std::experimental::extents<SizeType_x, ext_x ...>, Layout_x, Accessor_x> x,
  std::experimental::mdspan<ElementType_y, std::experimental::extents<SizeType_y, ext_y ...>, Layout_y, Accessor_y> y,
  std::experimental::mdspan<ElementType_z, std::experimental::extents<SizeType_z, ext_z ...>, Layout_z, Accessor_z> z)
{
  // this static assert is only here because for
  // the default case we support rank-1 and rank2.
  static_assert(z.rank() <= 2);

  if constexpr (z.rank() == 1) {
    add_rank_1 (x, y, z);
  }
  else if constexpr (z.rank() == 2) {
    add_rank_2 (x, y, z);
  }
}

MDSPAN_TEMPLATE_REQUIRES(
         class ExecutionPolicy,
         class ElementType_x,
	 class SizeType_x,
         ::std::size_t ... ext_x,
         class Layout_x,
         class Accessor_x,
         class ElementType_y,
	 class SizeType_y,
         ::std::size_t ... ext_y,
         class Layout_y,
         class Accessor_y,
	 class ElementType_z,
	 class SizeType_z,
         ::std::size_t ... ext_z,
         class Layout_z,
         class Accessor_z,
         /* requires */ (sizeof...(ext_x) == sizeof...(ext_y) && sizeof...(ext_x) == sizeof...(ext_z))
)
void add(
  ExecutionPolicy&& exec,
  std::experimental::mdspan<ElementType_x, std::experimental::extents<SizeType_x, ext_x ...>, Layout_x, Accessor_x> x,
  std::experimental::mdspan<ElementType_y, std::experimental::extents<SizeType_y, ext_y ...>, Layout_y, Accessor_y> y,
  std::experimental::mdspan<ElementType_z, std::experimental::extents<SizeType_z, ext_z ...>, Layout_z, Accessor_z> z)
{
  constexpr bool use_custom = is_custom_add_avail<
    decltype(detail::map_execpolicy_with_check(exec)), decltype(x), decltype(y), decltype(z)
    >::value;

  if constexpr (use_custom) {
    // for the customization point, it is up to impl to check requirements
    add(detail::map_execpolicy_with_check(exec), x, y, z);
  }
  else {
    add(std::experimental::linalg::impl::inline_exec_t(), x, y, z);
  }
}

MDSPAN_TEMPLATE_REQUIRES(
         class ElementType_x,
	 class SizeType_x,
         ::std::size_t ... ext_x,
         class Layout_x,
         class Accessor_x,
         class ElementType_y,
	 class SizeType_y,
         ::std::size_t ... ext_y,
         class Layout_y,
         class Accessor_y,
         class ElementType_z,
	 class SizeType_z,
         ::std::size_t ... ext_z,
         class Layout_z,
         class Accessor_z,
         /* requires */ (sizeof...(ext_x) == sizeof...(ext_y) && sizeof...(ext_x) == sizeof...(ext_z))
)
void add(
  std::experimental::mdspan<ElementType_x, std::experimental::extents<SizeType_x, ext_x ...>, Layout_x, Accessor_x> x,
  std::experimental::mdspan<ElementType_y, std::experimental::extents<SizeType_y, ext_y ...>, Layout_y, Accessor_y> y,
  std::experimental::mdspan<ElementType_z, std::experimental::extents<SizeType_z, ext_z ...>, Layout_z, Accessor_z> z)
{
  add(std::experimental::linalg::impl::default_exec_t(), x, y, z);
}

} // end namespace linalg
} // end inline namespace __p1673_version_0
} // end namespace experimental
} // end namespace std

#endif //LINALG_INCLUDE_EXPERIMENTAL___P1673_BITS_BLAS1_LINALG_ADD_HPP_