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 <typename... P, typename... Dims>
 ScatterView(::Kokkos::Impl::ViewCtorProp<P...> const& arg_prop, 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.

•  ScatterView(::Kokkos::Impl::ViewCtorProp<P...> const& arg_prop, Dims... dims);
  

  Constructor from variadic pack of dimension arguments. Constructs internal_view member. This constructor allows specifying an execution space instance to be used by passing, e.g., Kokkos::view_alloc(exec_space, “label”) as first argument.

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().