equal#

Header: <Kokkos_StdAlgorithms.hpp>

Description#

Returns true if two ranges or two rank-1 View s are equal.

Interface#

Warning

This is currently inside the Kokkos::Experimental namespace.

Overload set accepting execution space#

template <class ExecutionSpace, class IteratorType1, class IteratorType2>
bool equal(const ExecutionSpace& exespace,                                        (1)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2);

template <class ExecutionSpace, class IteratorType1, class IteratorType2>
bool equal(const std::string& label, const ExecutionSpace& exespace,              (2)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2);

template <class ExecutionSpace, class IteratorType1, class IteratorType2,
          class BinaryPredicateType>
bool equal(const ExecutionSpace& exespace,                                        (3)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2,
           BinaryPredicateType predicate);

template <class ExecutionSpace, class IteratorType1, class IteratorType2,
          class BinaryPredicateType>
bool equal(const std::string& label, const ExecutionSpace& exespace,              (4)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2,
           BinaryPredicateType predicate);

template <class ExecutionSpace, class IteratorType1, class IteratorType2>
bool equal(const ExecutionSpace& exespace, IteratorType1 first1,                  (5)
           IteratorType1 last1, IteratorType2 first2,
           IteratorType2 last2);

template <class ExecutionSpace, class IteratorType1, class IteratorType2>
bool equal(const std::string& label, const ExecutionSpace& exespace,              (6)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2, IteratorType2 last2);

template <class ExecutionSpace, class IteratorType1, class IteratorType2,
          class BinaryPredicateType>
bool equal(const ExecutionSpace& exespace,                                        (7)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2, IteratorType2 last2,
           BinaryPredicateType predicate);

template <class ExecutionSpace, class IteratorType1, class IteratorType2,
          class BinaryPredicateType>
bool equal(const std::string& label, const ExecutionSpace& exespace,              (8)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2, IteratorType2 last2,
           BinaryPredicateType predicate);

template <class ExecutionSpace, class DataType1, class... Properties1,
          class DataType2, class... Properties2>
bool equal(const ExecutionSpace& exespace,                                        (9)
           const Kokkos::View<DataType1, Properties1...>& view1,
           const Kokkos::View<DataType2, Properties2...>& view2);

template <class ExecutionSpace, class DataType1, class... Properties1,
          class DataType2, class... Properties2>
bool equal(const std::string& label, const ExecutionSpace& exespace,             (10)
           const Kokkos::View<DataType1, Properties1...>& view1,
           const Kokkos::View<DataType2, Properties2...>& view2);

template <class ExecutionSpace, class DataType1, class... Properties1,
          class DataType2, class... Properties2, class BinaryPredicate>
bool equal(const ExecutionSpace& exespace,                                       (11)
           const Kokkos::View<DataType1, Properties1...>& view1,
           const Kokkos::View<DataType2, Properties2...>& view2,
           BinaryPredicate pred);

template <class ExecutionSpace, class DataType1, class... Properties1,
          class DataType2, class... Properties2, class BinaryPredicate>
bool equal(const std::string& label, const ExecutionSpace& exespace,             (12)
           const Kokkos::View<DataType1, Properties1...>& view1,
           const Kokkos::View<DataType2, Properties2...>& view2,
           BinaryPredicate pred);

Overload set accepting a team handle#

New in version 4.2.

template <class TeamHandleType, class IteratorType1, class IteratorType2>
KOKKOS_FUNCTION
bool equal(const TeamHandleType& teamHandle,                                     (13)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2);

template <class TeamHandleType, class IteratorType1, class IteratorType2,
          class BinaryPredicateType>
KOKKOS_FUNCTION
bool equal(const TeamHandleType& teamHandle,                                     (14)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2,
           BinaryPredicateType predicate);

template <class TeamHandleType, class IteratorType1, class IteratorType2>
KOKKOS_FUNCTION
bool equal(const TeamHandleType& teamHandle,                                     (15)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2, IteratorType2 last2);

template <class TeamHandleType, class IteratorType1, class IteratorType2,
          class BinaryPredicateType>
KOKKOS_FUNCTION
bool equal(const TeamHandleType& teamHandle,                                     (16)
           IteratorType1 first1, IteratorType1 last1,
           IteratorType2 first2, IteratorType2 last2,
           BinaryPredicateType predicate);

template <class TeamHandleType, class DataType1, class... Properties1,
          class DataType2, class... Properties2>
KOKKOS_FUNCTION
bool equal(const TeamHandleType& teamHandle,                                     (17)
           const Kokkos::View<DataType1, Properties1...>& view1,
           const Kokkos::View<DataType2, Properties2...>& view2);

template <class TeamHandleType, class DataType1, class... Properties1,
          class DataType2, class... Properties2, class BinaryPredicate>
KOKKOS_FUNCTION
bool equal(const TeamHandleType& teamHandle,                                     (18)
           const Kokkos::View<DataType1, Properties1...>& view1,
           const Kokkos::View<DataType2, Properties2...>& view2,
           BinaryPredicate pred);

Overload Set Detailed Description#

  • (1,2,3,4,13,14): returns true if the range [first1, last1) is equal to the range [first2, first2 + (last1 - first1)), and false otherwise

  • (5,6,7,8,15,16): returns true if the range [first1, last1) is equal to the range [first2, last2), and false otherwise

  • (9,10,11,12,17,18): returns true if view1 and view2 are equal and false otherwise

  • where applicable, the binary predicate pred is used to check equality between two elements, otherwise operator == is used

Parameters and Requirements#

  • exespace: execution space instance

  • teamHandle: team handle instance given inside a parallel region when using a TeamPolicy

  • label: string forwarded to internal parallel kernels for debugging purposes

    • (1,3,5,7): The default string is “Kokkos::equal_iterator_api_default”

    • (9,11): The default string is “Kokkos::equal_view_api_default”

    • NOTE: overloads accepting a team handle do not use a label internally

  • first1, last1, first2, last2: iterators defining the ranges to read and compare

    • must be random access iterators, e.g., returned from Kokkos::Experimental::(c)begin/(c)end

    • must represent a valid range, i.e., last1 >= first1

    • must be accessible from exespace or from the execution space associated with the team handle

  • view1, view2: views to compare

    • must be rank-1, and have LayoutLeft, LayoutRight, or LayoutStride

    • must be accessible from exespace or from the execution space associated with the team handle

  • pred: binary functor returning true if two arguments should be considered “equal”.

    pred(a,b) must be valid to be called from the execution space passed, or the execution space associated with the team handle, and convertible to bool for every pair of arguments a,b of type ValueType1 and ValueType2, respectively, ValueType1 and ValueType{1,2} are the value types of IteratorType{1,2} or view{1,2}, and must not modify a,b.

    • must conform to:

    template <class ValueType1, class ValueType2 = ValueType1>
struct IsEqualFunctor {
 KOKKOS_INLINE_FUNCTION
 bool operator()(const ValueType1& a, const ValueType2& b) const {
   return (a == b);
 }
};

Return Value#

If the elements of the two ranges or Views are equal, returns true, otherwise false.

Corner cases when false is returned:

  • if view1.extent(0) != view2.extent(1) for all overloads accepting Views

  • if the length of the range [first1, last) is not equal to length of [first2,last2)

Example#

namespace KE = Kokkos::Experimental;

template <class ValueType1, class ValueType2 = ValueType1>
struct IsEqualFunctor {
  KOKKOS_INLINE_FUNCTION
  bool operator()(const ValueType1& a, const ValueType2& b) const {
    return (a == b);
  }
};

auto exespace = Kokkos::DefaultExecutionSpace;
using view_type = Kokkos::View<exespace, int*>;
view_type a("a", 15);
view_type b("b", 15);
// fill a,b somehow

// create functor
IsEqualFunctor<int,int> p();

bool isEqual = KE::equal(exespace, KE::begin(a), KE::end(a),
                         KE::begin(b), KE::end(b) p);

// To run explicitly on the host (assuming a and b are accessible on Host)
bool isEqual = KE::equal(Kokkos::DefaultHostExecutionSpace(), KE::begin(a), KE::end(a),
                         KE::begin(b), KE::end(b), p);