hpx::copy_if

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hpx::copy_if#

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:

template<typename ExPolicy, typename FwdIter1, typename FwdIter2, typename Pred>
hpx::parallel::util::detail::algorithm_result_t<ExPolicy, FwdIter2> hpx::copy_if(ExPolicy &&policy, FwdIter1 first, FwdIter1 last, FwdIter2 dest, Pred &&pred)#

Copies the elements in the range, defined by [first, last), to another range beginning at dest. Copies only the elements for which the predicate f returns true. The order of the elements that are not removed is preserved. Executed according to the policy.

The assignments in the parallel copy_if algorithm invoked with an execution policy object of type sequenced_policy execute in sequential order in the calling thread.

The assignments in the parallel copy_if 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.

Note

Complexity: Performs not more than last - first assignments, exactly last - first applications of the predicate f.

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 assignments.

  • FwdIter1 – The type of the source iterators used (deduced). This iterator type must meet the requirements of an forward iterator.

  • FwdIter2 – The type of the iterator representing the destination range (deduced). This iterator type must meet the requirements of an forward iterator.

  • Pred – The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of copy_if requires F to meet the requirements of CopyConstructible.

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.

  • dest – Refers to the beginning of the destination range.

  • pred – Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last).This is an unary predicate which returns true for the required elements. The signature of this predicate should be equivalent to: 

    bool pred(const Type &a);
    The signature does not need to have const&, but the function must not modify the objects passed to it. The type Type must be such that an object of type FwdIter1 can be dereferenced and then implicitly converted to Type.

Returns:

The copy_if algorithm returns a hpx::future<FwdIter2> > if the execution policy is of type sequenced_task_policy or parallel_task_policy and returns FwdIter2 otherwise. The copy_if algorithm returns output iterator to the element in the destination range, one past the last element copied.

template<typename FwdIter1, typename FwdIter2, typename Pred>
FwdIter2 hpx::copy_if(FwdIter1 first, FwdIter1 last, FwdIter2 dest, Pred &&pred)#

Copies the elements in the range, defined by [first, last), to another range beginning at dest. Copies only the elements for which the predicate f returns true. The order of the elements that are not removed is preserved.

Note

Complexity: Performs not more than last - first assignments, exactly last - first applications of the predicate f.

Template Parameters:

  • FwdIter1 – The type of the source iterators used (deduced). This iterator type must meet the requirements of an forward iterator.

  • FwdIter2 – The type of the iterator representing the destination range (deduced). This iterator type must meet the requirements of an forward iterator.

  • Pred – The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of copy_if requires F to meet the requirements of CopyConstructible.

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.

  • dest – Refers to the beginning of the destination range.

  • pred – Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last).This is an unary predicate which returns true for the required elements. The signature of this predicate should be equivalent to: 

    bool pred(const Type &a);
    The signature does not need to have const&, but the function must not modify the objects passed to it. The type Type must be such that an object of type FwdIter1 can be dereferenced and then implicitly converted to Type.

Returns:

The copy_if algorithm returns a FwdIter2 . The copy_if algorithm returns output iterator to the element in the destination range, one past the last element copied.

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