HPX - High Performance ParalleX

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Function template replace_if

hpx::parallel::v1::replace_if

Synopsis

// In header: <hpx/parallel/algorithms/replace.hpp>


template<typename ExPolicy, typename FwdIter, typename F, typename T> 
  unspecified replace_if(ExPolicy && policy, FwdIter first, FwdIter last, 
                         F && f, T const & new_value);

Description

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

[Note] Note

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

The assignments in the parallel replace_if algorithm invoked with an execution policy object of type sequential_execution_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_execution_policy or parallel_task_execution_policy are permitted to execute in an unordered fashion in unspecified threads, and indeterminately sequenced within each thread.

Parameters:

f

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.

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.

new_value

Refers to the new value to use as the replacement.

policy

The execution policy to use for the scheduling of the iterations.

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.

F

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

FwdIter

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

T

The type of the new values to replace (deduced).

Returns:

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


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