replace_if

Header File: Kokkos_StdAlgorithms.hpp

namespace Kokkos{
namespace Experimental{

template <class ExecutionSpace, class IteratorType, class UnaryPredicateType, class T>
void replace_if(const ExecutionSpace& exespace,                              (1)
                IteratorType first, IteratorType last,
                UnaryPredicateType pred, const T& new_value);

template <class ExecutionSpace, class IteratorType, class UnaryPredicateType, class T>
void replace_if(const std::string& label, const ExecutionSpace& exespace,    (2)
                IteratorType first, IteratorType last,
                UnaryPredicateType pred, const T& new_value);

template <class ExecutionSpace, class DataType, class... Properties, class UnaryPredicateType, class T>
void replace_if(const ExecutionSpace& exespace,                              (3)
                const Kokkos::View<DataType, Properties...>& view,
                UnaryPredicateType pred, const T& new_value);

template <class ExecutionSpace, class DataType, class... Properties, class UnaryPredicateType, class T>
void replace_if(const std::string& label, const ExecutionSpace& exespace,    (4)
                const Kokkos::View<DataType, Properties...>& view,
                UnaryPredicateType pred, const T& new_value);

} //end namespace Experimental
} //end namespace Kokkos

Description

Replaces with new_value all the elements for which pred is true in the range [first, last) (overloads 1,2) or in view (overloads 3,4).

Parameters and Requirements

• exespace, first, last, view, new_value: same as in replace

• label:

  • for 1, the default string is: “Kokkos::replace_if_iterator_api_default”

  • for 3, the default string is: “Kokkos::replace_if_view_api_default”

• pred:

  • unary predicate returning true for the required element to replace; pred(v) must be valid to be called from the execution space passed, and convertible to bool for every argument v of type (possible const) value_type, where value_type is the value type of IteratorType (for 1,2) or the value type of view (for 3,4), and must not modify v.

  • must conform to:

  struct Predicate
  {
     KOKKOS_INLINE_FUNCTION
     bool operator()(const value_type & v) const { return /* ... */; }
  
     // or, also valid
  
     KOKKOS_INLINE_FUNCTION
     bool operator()(value_type v) const { return /* ... */; }
  };
  

Return

None

Example

template <class ValueType>
struct IsPositiveFunctor {
  KOKKOS_INLINE_FUNCTION
  bool operator()(const ValueType val) const { return (val > 0); }
};
// ---

namespace KE = Kokkos::Experimental;
Kokkos::View<double*> a("a", 13);
// do something with a
// ...

const double oldValue{2};
const double newValue{34};
KE::replace_if(Kokkos::DefaultExecutionSpace(), KE::begin(a), KE::end(a),
   IsPositiveFunctor<double>(), newValue);

// explicitly set label and execution space (assuming active)
KE::replace_if("mylabel", Kokkos::OpenMP(), a,
   IsPositiveFunctor<double>(), newValue);