MinMax

Specific implementation of ReducerConcept storing both the minimum and maximum values

Header File: <Kokkos_Core.hpp>

Usage

MinMax<T,S>::value_type result;
parallel_reduce(N,Functor,MinMax<T,S>(result));

Synopsis

template<class Scalar, class Space>
class MinMax{
  public:
    typedef MinMax reducer;
    typedef MinMaxScalar<typename std::remove_cv<Scalar>::type> value_type;
    typedef Kokkos::View<value_type, Space> result_view_type;

    KOKKOS_INLINE_FUNCTION
    void join(value_type& dest, const value_type& src) const;

    KOKKOS_INLINE_FUNCTION
    void init(value_type& val) const;

    KOKKOS_INLINE_FUNCTION
    value_type& reference() const;

    KOKKOS_INLINE_FUNCTION
    result_view_type view() const;

    KOKKOS_INLINE_FUNCTION
    MinMax(value_type& value_);

    KOKKOS_INLINE_FUNCTION
    MinMax(const result_view_type& value_);
};

Interface

template<class Scalar, class Space>
class MinMax

Public Types

reducer

The self type.

value_type

The reduction scalar type (specialization of MinMaxScalar)

result_view_type

A Kokkos::View referencing the reduction result

Constructors

KOKKOS_INLINE_FUNCTION MinMax(value_type &value_);

Constructs a reducer which references a local variable as its result location.

KOKKOS_INLINE_FUNCTION MinMax(const result_view_type &value_);

Constructs a reducer which references a specific view as its result location.

Public Member Functions

KOKKOS_INLINE_FUNCTION void join(value_type &dest, const value_type &src) const;

Store minimum of src and dest into dest: dest.min_val = (src.min_val < dest.min_val) ? src.min_val :dest.min_val;. Store maximum of src and dest into dest: dest.max_val = (src.max_val < dest.max_val) ? src.max_val :dest.max_val;.

KOKKOS_INLINE_FUNCTION void init(value_type &val) const;

Initialize val.min_val using the Kokkos::reduction_identity<Scalar>::min() method. The default implementation sets val=<TYPE>_MAX. Initialize val.max_val using the Kokkos::reduction_identity<Index>::max() method. The default implementation sets val=<TYPE>_MIN.

KOKKOS_INLINE_FUNCTION value_type &reference() const;

Returns a reference to the result provided in class constructor.

KOKKOS_INLINE_FUNCTION result_view_type view() const;

Returns a view of the result place provided in class constructor.

Additional Information

• MinMax<T,S>::value_type is Specialization of MinMaxScalar on non-const T

• MinMax<T,S>::result_view_type is Kokkos::View<T,S,Kokkos::MemoryTraits<Kokkos::Unmanaged>>. Note that the S (memory space) must be the same as the space where the result resides.

• Requires: Scalar has operator =, operator < and operator > defined. Kokkos::reduction_identity<Scalar>::min() and Kokkos::reduction_identity<Scalar>::max() are a valid expressions.

• In order to use MinMax with a custom type of Scalar, a template specialization of Kokkos::reduction_identity<CustomType> must be defined. See Built-In Reducers with Custom Scalar Types for details