for_each.hpp¶

See Public API for a list of names and headers that are part of the public HPX API.

namespace hpx

namespace ranges

Functions

template<typename InIter, typename Sent, typename F, typename Proj = util::projection_identity> hpx::ranges::for_each_result<InIter, F> for_each(InIter first, Sent last, F &&f, Proj &&proj = Proj())¶

Applies f to the result of dereferencing every iterator in the range [first, last).

If

f returns a result, the result is ignored.

Note: Complexity: Applies f exactly last - first times.

If the type of first satisfies the requirements of a mutable iterator, f may apply non-constant functions through the dereferenced iterator.

Applies

f to the result of dereferencing every iterator in the range [first, first + count), starting from first and proceeding to first + count - 1.

Return

{last, HPX_MOVE(f)} where last is the iterator corresponding to the input sentinel last.

Template Parameters

InIter: The type of the source begin iterator used (deduced). This iterator type must meet the requirements of an input iterator.
Sent: The type of the source sentinel (deduced). This sentinel type must be a sentinel for InIter.
F: The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of for_each requires F to meet the requirements of CopyConstructible.
Proj: The type of an optional projection function. This defaults to util::projection_identity

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.
f: Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last). The signature of this predicate should be equivalent to:
```
<ignored> pred(const Type &a);
```
The signature does not need to have const&. The type
Type must be such that an object of type InIter can be dereferenced and then implicitly converted to Type.
proj: Specifies the function (or function object) which will be invoked for each of the elements as a projection operation before the actual predicate is invoked.

If

f returns a result, the result is ignored.

Note: Complexity: Applies f exactly last - first times.

If the type of first satisfies the requirements of a mutable iterator, f may apply non-constant functions through the dereferenced iterator.

Return

{first + count, HPX_MOVE(f)}

Template Parameters

InIter: The type of the source begin iterator used (deduced). This iterator type must meet the requirements of an input iterator.
Size: The type of the argument specifying the number of elements to apply f to.
F: The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of for_each requires F to meet the requirements of CopyConstructible.
Proj: The type of an optional projection function. This defaults to util::projection_identity

Parameters

first: Refers to the beginning of the sequence of elements the algorithm will be applied to.
count: Refers to the number of elements starting at first the algorithm will be applied to.
f: Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last). The signature of this predicate should be equivalent to:
```
<ignored> pred(const Type &a);
```
The signature does not need to have const&. The type
Type must be such that an object of type InIter can be dereferenced and then implicitly converted to Type.
proj: Specifies the function (or function object) which will be invoked for each of the elements as a projection operation before the actual predicate is invoked.

template<typename ExPolicy, typename FwdIter, typename Sent, typename F, typename Proj = util::projection_identity> FwdIter for_each(ExPolicy &&policy, FwdIter first, Sent last, F &&f, Proj &&proj = Proj())¶

Applies f to the result of dereferencing every iterator in the range [first, last).

If

f returns a result, the result is ignored.

Note: Complexity: Applies f exactly last - first times.

If the type of first satisfies the requirements of a mutable iterator, f may apply non-constant functions through the dereferenced iterator.

Unlike its sequential form, the parallel overload of for_each does not return a copy of its Function parameter, since parallelization may not permit efficient state accumulation.

Return

The for_each algorithm returns a hpx::future<FwdIter> if the execution policy is of type sequenced_task_policy or parallel_task_policy and returns FwdIter otherwise. It returns last.

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 applies user-provided function objects.
FwdIter: The type of the source begin iterator used (deduced). This iterator type must meet the requirements of an forward iterator.
Sent: The type of the source sentinel (deduced). This sentinel type must be a sentinel for InIter.
F: The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of for_each requires F to meet the requirements of CopyConstructible.
Proj: The type of an optional projection function. This defaults to util::projection_identity

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.
f: Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last). The signature of this predicate should be equivalent to:
```
<ignored> pred(const Type &a);
```
The signature does not need to have const&. The type
Type must be such that an object of type InIter can be dereferenced and then implicitly converted to Type.
proj: Specifies the function (or function object) which will be invoked for each of the elements as a projection operation before the actual predicate is invoked.

template<typename Rng, typename F, typename Proj = util::projection_identity> hpx::ranges::for_each_result<typename hpx::traits::range_iterator<Rng>::type, F> for_each(ExPolicy &&policy, Rng &&rng, F &&f, Proj &&proj = Proj())¶

Applies f to the result of dereferencing every iterator in the given range rng.

If

f returns a result, the result is ignored.

Note: Complexity: Applies f exactly size(rng) times.

If the type of first satisfies the requirements of a mutable iterator, f may apply non-constant functions through the dereferenced iterator.

Return

{std::end(rng), HPX_MOVE(f)}

Template Parameters

Rng: The type of the source range used (deduced). The iterators extracted from this range type must meet the requirements of an input iterator.
F: The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of for_each requires F to meet the requirements of CopyConstructible.
Proj: The type of an optional projection function. This defaults to util::projection_identity

Parameters

policy: The execution policy to use for the scheduling of the iterations.
rng: Refers to the sequence of elements the algorithm will be applied to.
f: Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last). The signature of this predicate should be equivalent to:
```
<ignored> pred(const Type &a);
```
The signature does not need to have const&. The type
Type must be such that an object of type InIter can be dereferenced and then implicitly converted to Type.
proj: Specifies the function (or function object) which will be invoked for each of the elements as a projection operation before the actual predicate is invoked.

template<typename ExPolicy, typename Rng, typename F, typename Proj = util::projection_identity> util::detail::algorithm_result<ExPolicy, typename hpx::traits::range_iterator<Rng>::type>::type for_each(ExPolicy &&policy, Rng &&rng, F &&f, Proj &&proj = Proj())¶

Applies f to the result of dereferencing every iterator in the given range rng.

If

f returns a result, the result is ignored.

Note: Complexity: Applies f exactly size(rng) times.

If the type of first satisfies the requirements of a mutable iterator, f may apply non-constant functions through the dereferenced iterator.

Unlike its sequential form, the parallel overload of for_each does not return a copy of its Function parameter, since parallelization may not permit efficient state accumulation.

The application of function objects in parallel algorithm invoked with an execution policy object of type

sequenced_policy execute in sequential order in the calling 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 applies user-provided function objects.
Rng: The type of the source range used (deduced). The iterators extracted from this range type must meet the requirements of an input iterator.
F: The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of for_each requires F to meet the requirements of CopyConstructible.
Proj: The type of an optional projection function. This defaults to util::projection_identity

Parameters

policy: The execution policy to use for the scheduling of the iterations.
rng: Refers to the sequence of elements the algorithm will be applied to.
f: Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last). The signature of this predicate should be equivalent to:
```
<ignored> pred(const Type &a);
```
The signature does not need to have const&. The type
Type must be such that an object of type InIter can be dereferenced and then implicitly converted to Type.
proj: Specifies the function (or function object) which will be invoked for each of the elements as a projection operation before the actual predicate is invoked.

The application of function objects in parallel 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.

Return: The for_each algorithm returns a hpx::future<FwdIter> if the execution policy is of type sequenced_task_policy or parallel_task_policy and returns FwdIter otherwise. It returns last.

template<typename ExPolicy, typename FwdIter, typename Size, typename F, typename Proj = util::projection_identity> util::detail::algorithm_result<ExPolicy, FwdIter>::type for_each_n(ExPolicy &&policy, FwdIter first, Size count, F &&f, Proj &&proj = Proj())¶

Applies f to the result of dereferencing every iterator in the range [first, first + count), starting from first and proceeding to first + count - 1.

If

f returns a result, the result is ignored.

Note: Complexity: Applies f exactly count times.

If the type of first satisfies the requirements of a mutable iterator, f may apply non-constant functions through the dereferenced iterator.

Unlike its sequential form, the parallel overload of for_each does not return a copy of its Function parameter, since parallelization may not permit efficient state accumulation.

Return

The for_each algorithm returns a hpx::future<FwdIter> if the execution policy is of type sequenced_task_policy or parallel_task_policy and returns FwdIter otherwise. It returns last.

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 applies user-provided function objects.
FwdIter: The type of the source begin iterator used (deduced). This iterator type must meet the requirements of an forward iterator.
Size: The type of the argument specifying the number of elements to apply f to.
F: The type of the function/function object to use (deduced). Unlike its sequential form, the parallel overload of for_each requires F to meet the requirements of CopyConstructible.
Proj: The type of an optional projection function. This defaults to util::projection_identity

Parameters

first: Refers to the beginning of the sequence of elements the algorithm will be applied to.
count: Refers to the number of elements starting at first the algorithm will be applied to.
f: Specifies the function (or function object) which will be invoked for each of the elements in the sequence specified by [first, last). The signature of this predicate should be equivalent to:
```
<ignored> pred(const Type &a);
```
The signature does not need to have const&. The type
Type must be such that an object of type InIter can be dereferenced and then implicitly converted to Type.
proj: Specifies the function (or function object) which will be invoked for each of the elements as a projection operation before the actual predicate is invoked.