hpx::replace_if

hpx::replace_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 Iter, typename Pred, typename T = typename std::iterator_traits<Iter>::value_type>
void hpx::replace_if(Iter first, Iter last, Pred &&pred, T const &new_value)#

Replaces all elements satisfying specific criteria (for which predicate pred returns true) with new_value in the range [first, last).

Effects: Substitutes elements referred by the iterator it in the range [first, last) with new_value, when the following corresponding conditions hold: INVOKE(f, *it) != false

The assignments in the parallel replace_if algorithm execute in sequential order in the calling thread.

Note

Complexity: Performs exactly last - first applications of the predicate.

Template Parameters:

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

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

  • T – The type of the new values to replace (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.

  • 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 elements which need to replaced. 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 InIter can be dereferenced and then implicitly converted to Type.

  • new_value – Refers to the new value to use as the replacement.

Returns:

The replace_if algorithm returns void.

template<typename ExPolicy, typename FwdIter, typename Pred, typename T = typename std::iterator_traits<FwdIter>::value_type>
hpx::parallel::util::detail::algorithm_result_t<ExPolicy, void> hpx::replace_if(ExPolicy &&policy, FwdIter first, FwdIter last, Pred &&pred, T const &new_value)#

Replaces all elements satisfying specific criteria (for which predicate f returns true) with new_value in the range [first, last). Executed according to the policy.

Effects: Substitutes elements referred by the iterator it in the range [first, last) with new_value, when the following corresponding conditions hold: INVOKE(f, *it) != false

The assignments in the parallel replace_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 replace_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 exactly last - first applications of the predicate.

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.

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

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

  • T – The type of the new values to replace (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.

  • 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 elements which need to replaced. 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 FwdIter can be dereferenced and then implicitly converted to Type.

  • new_value – Refers to the new value to use as the replacement.

Returns:

The replace_if algorithm returns a hpx::future<void> if the execution policy is of type sequenced_task_policy or parallel_task_policy and returns void otherwise.

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