Kokkos::ScatterView

Kokkos::ScatterView

Header File: Kokkos_ScatterView.hpp

Usage:

KOKKOS_INLINE_FUNCTION int foo(int i) { return i; }
KOKKOS_INLINE_FUNCTION double bar(int i) { return i*i; }

Kokkos::View<double*> results("results", 1);
Kokkos::Experimental::ScatterView<double*> scatter(results);
Kokkos::parallel_for(1, KOKKOS_LAMBDA(int input_i) {
  auto access = scatter.access();
  auto result_i = foo(input_i);
  auto contribution = bar(input_i);
  access(result_i) += contribution;
});
Kokkos::Experimental::contribute(results, scatter);

Synopsis

template <typename DataType
         ,int Op
         ,typename ExecSpace
         ,typename Layout
         ,int contribution
         >
class ScatterView<DataType
                   ,Layout
                   ,ExecSpace
                   ,Op
                   ,{ScatterNonDuplicated,ScatterDuplicated}
                   ,contribution>
{
public:
  typedef Kokkos::View<DataType, Layout, ExecSpace> original_view_type;
  typedef typename original_view_type::value_type original_value_type;
  typedef typename original_view_type::reference_type original_reference_type;
  friend class ScatterAccess<DataType, Op, ExecSpace, Layout, {ScatterNonDuplicated,ScatterDuplicated}, contribution, ScatterNonAtomic>;
  friend class ScatterAccess<DataType, Op, ExecSpace, Layout, {ScatterNonDuplicated,ScatterDuplicated}, contribution, ScatterAtomic>;
  typedef typename Kokkos::Impl::Experimental::DuplicatedDataType<DataType, {Kokkos::LayoutRight,Kokkos::LayoutLeft}> data_type_info; // ScatterDuplicated only
  typedef typename data_type_info::value_type internal_data_type; // ScatterDuplicated only
  typedef Kokkos::View<internal_data_type, {Kokkos::LayoutRight,Kokkos::LayoutLeft}, ExecSpace> internal_view_type; // ScatterDuplicated only
  
  ScatterView();

  template <typename RT, typename ... RP>
  ScatterView(View<RT, RP...> const& );

  template <typename ... Dims>
  ScatterView(std::string const& name, Dims ... dims);

  template <int override_contrib = contribution>
  KOKKOS_FORCEINLINE_FUNCTION
  ScatterAccess<DataType, Op, ExecSpace, Layout, ScatterNonDuplicated, contribution, override_contrib>
  access() const;

  original_view_type subview() const;

  template <typename DT, typename ... RP>
  void contribute_into(View<DT, RP...> const& dest) const;

  void reset();
  
  template <typename DT, typename ... RP>
  void reset_except(View<DT, RP...> const& view);

  void resize(const size_t n0 = 0,
           const size_t n1 = 0,
           const size_t n2 = 0,
           const size_t n3 = 0,
           const size_t n4 = 0,
           const size_t n5 = 0,
           const size_t n6 = 0,
           const size_t n7 = 0);

  void realloc(const size_t n0 = 0,
           const size_t n1 = 0,
           const size_t n2 = 0,
           const size_t n3 = 0,
           const size_t n4 = 0,
           const size_t n5 = 0,
           const size_t n6 = 0,
           const size_t n7 = 0);

protected:
  template <typename ... Args>
  KOKKOS_FORCEINLINE_FUNCTION
  original_reference_type at(Args ... args) const;
  
private:
  typedef original_view_type internal_view_type;
  internal_view_type internal_view;
};

Public Class Members

Typedefs

• original_view_type: Type of View passed to ScatterView constructor.
• original_value_type: Value type of the original_view_type.
• original_reference_type: Reference type of the original_view_type. // ScatterDuplicated only
• data_type_info: DuplicatedDataType, a newly created DataType that has a new runtime dimension which becomes the largest-stride dimension, from the given View DataType.
• internal_data_type: Value type of data_type_info.
• internal_view_type: A View type created from the internal_data_type.

Constructors

•  ScatterView();

  Default constructor. Default constructs members.

•  ScatterView(View<RT, RP...> const& );

  Constructor from a Kokkos::View. internal_view member is copy constructed from this input view.

•  ScatterView(std::string const& name, Dims ... dims);

  Constructor from variadic pack of dimension arguments. Constructs internal_view member.

Functions

• constexpr bool is_allocated() const;

  Returns true if the internal_view points to a valid memory location. This function works for both managed and unmanaged views. With the unmanaged view, there is no guarantee that referenced address is valid, only that it is a non-null pointer.

•  access() const;

  Use within a kernel to return a ScatterAccess member; this member accumulates a given thread's contribution to the reduction.

•  subview() const;

  Return a subview of a ScatterView.

•  contribute_into(View<DT, RP...> const& dest) const;

  Contribute ScatterView array's results into the input View dest.

•  reset();

  Performs reset on destination array.

•  reset_except(View<DT, RP...> const& view);

•  resize(const size_t n0 = 0, const size_t n1 = 0, const size_t n2 = 0, const size_t n3 = 0, const size_t n4 = 0, const size_t n5 = 0, const size_t n6 = 0, const size_t n7 = 0);

  Resize a view with copying old data to new data at the corresponding indices.

•  realloc(const size_t n0 = 0, const size_t n1 = 0, const size_t n2 = 0, const size_t n3 = 0, const size_t n4 = 0, const size_t n5 = 0, const size_t n6 = 0, const size_t n7 = 0);

  Resize a view with discarding old data.

Free Functions

• contribute(View<DT1, VP...>& dest, Kokkos::Experimental::ScatterView<DT2, LY, ES, OP, CT, DP> const& src)

  Convenience function to perform final reduction of ScatterView results into a resultant View; may be called following parallel_reduce.