DenseVector/Kokkos/Morpheus_Reduction_Impl.hpp

 
#ifndef MORPHEUS_DENSEVECTOR_KOKKOS_REDUCTION_IMPL_HPP
#define MORPHEUS_DENSEVECTOR_KOKKOS_REDUCTION_IMPL_HPP
 
#include <Morpheus_SpaceTraits.hpp>
#include <Morpheus_FormatTraits.hpp>
#include <Morpheus_FormatTags.hpp>
#include <Morpheus_Spaces.hpp>
 
namespace Morpheus {
namespace Impl {
 
template <typename ExecSpace, typename Vector>
typename Vector::value_type reduce(
    const Vector& in, typename Vector::size_type size,
    typename std::enable_if_t<
        Morpheus::is_dense_vector_format_container_v<Vector> &&
        Morpheus::has_generic_backend_v<ExecSpace> &&
        Morpheus::has_access_v<ExecSpace, Vector>>* = nullptr) {
  using execution_space = typename ExecSpace::execution_space;
  using size_type       = typename Vector::size_type;
  using IndexType       = Kokkos::IndexType<size_type>;
  using range_policy    = Kokkos::RangePolicy<IndexType, execution_space>;
  using ValueArray      = typename Vector::value_array_type;
  using value_type      = typename Vector::non_const_value_type;
 
  const ValueArray in_view = in.const_view();
  range_policy policy(0, size);
 
  value_type result = value_type(0);
  Kokkos::parallel_reduce(
      "reduce", policy,
      KOKKOS_LAMBDA(const size_type& i, value_type& lsum) {
        lsum += in_view[i];
      },
      result);
 
  return result;
}
 
}  // namespace Impl
}  // namespace Morpheus
 
#endif  // MORPHEUS_DENSEVECTOR_KOKKOS_REDUCTION_IMPL_HPP