hpx::count#
Defined in header hpx/algorithm.hpp.
See Public API for a list of names and headers that are part of the public HPX API.
See also:
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template<typename ExPolicy, typename FwdIter, typename T>
util::detail::algorithm_result<ExPolicy, typename std::iterator_traits<FwdIter>::difference_type>::type hpx::count(ExPolicy &&policy, FwdIter first, FwdIter last, T const &value)# Returns the number of elements in the range [first, last) satisfying a specific criteria. This version counts the elements that are equal to the given value. Executed according to the policy.
The comparisons in the parallel count algorithm invoked with an execution policy object of type sequenced_policy execute in sequential order in the calling thread.
Note
Complexity: Performs exactly last - first comparisons.
Note
The comparisons in the parallel count algorithm invoked with an execution policy object of type parallel_policy or parallel_task_policy are permitted to execute in an unordered fashion in unspecified threads, and indeterminately sequenced within each thread.
- Template Parameters:
ExPolicy – The type of the execution policy to use (deduced). It describes the manner in which the execution of the algorithm may be parallelized and the manner in which it executes the comparisons.
FwdIter – The type of the source iterator used (deduced). This iterator type must meet the requirements of an forward iterator.
T – The type of the value to search for (deduced).
- Parameters:
policy – The execution policy to use for the scheduling of the iterations.
first – Refers to the beginning of the sequence of elements the algorithm will be applied to.
last – Refers to the end of the sequence of elements the algorithm will be applied to.
value – The value to search for.
- Returns:
The count algorithm returns a hpx::future<difference_type> if the execution policy is of type sequenced_task_policy or parallel_task_policy and returns difference_type otherwise (where difference_type is defined by std::iterator_traits<FwdIterB>::difference_type. The count algorithm returns the number of elements satisfying the given criteria.
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template<typename InIter, typename T>
std::iterator_traits<InIter>::difference_type hpx::count(InIter first, InIter last, T const &value)# Returns the number of elements in the range [first, last) satisfying a specific criteria. This version counts the elements that are equal to the given value.
Note
Complexity: Performs exactly last - first comparisons.
- Template Parameters:
InIter – The type of the source iterator used (deduced). This iterator type must meet the requirements of an input iterator.
T – The type of the value to search for (deduced).
- Parameters:
first – Refers to the beginning of the sequence of elements the algorithm will be applied to.
last – Refers to the end of the sequence of elements the algorithm will be applied to.
value – The value to search for.
- Returns:
The count algorithm returns a difference_type (where difference_type is defined by std::iterator_traits<InIter>::difference_type. The count algorithm returns the number of elements satisfying the given criteria.