15#ifndef dealii_thread_management_h
16#define dealii_thread_management_h
36#ifdef DEAL_II_HAVE_CXX20
41#ifdef DEAL_II_WITH_TBB
42# include <tbb/task_group.h>
75 template <
typename ForwardIterator>
76 std::vector<std::pair<ForwardIterator, ForwardIterator>>
78 const ForwardIterator &end,
79 const unsigned int n_intervals);
89 std::vector<std::pair<unsigned int, unsigned int>>
91 const unsigned int end,
92 const unsigned int n_intervals);
144 template <
typename ForwardIterator>
145 std::vector<std::pair<ForwardIterator, ForwardIterator>>
147 const ForwardIterator &end,
148 const unsigned int n_intervals)
150 using IteratorPair = std::pair<ForwardIterator, ForwardIterator>;
156 if (n_intervals == 1)
157 return (std::vector<IteratorPair>(1, IteratorPair(begin, end)));
160 const unsigned int n_elements = std::distance(begin, end);
161 const unsigned int n_elements_per_interval = n_elements / n_intervals;
162 const unsigned int residual = n_elements % n_intervals;
164 std::vector<IteratorPair> return_values(n_intervals);
166 return_values[0].first =
begin;
167 for (
unsigned int i = 0; i < n_intervals; ++i)
169 if (i != n_intervals - 1)
171 return_values[i].second = return_values[i].first;
176 std::advance(return_values[i].
second,
177 static_cast<signed int>(n_elements_per_interval));
181 ++return_values[i].second;
183 return_values[i + 1].first = return_values[i].second;
186 return_values[i].second =
end;
188 return return_values;
216 template <
typename RT>
237 "You cannot read the return value of a thread or task "
238 "if that value has not been set. This happens, for example, if "
239 "a task or thread threw an exception."));
246 value = std::move(v);
261 value = std::move(v.get());
286 template <
typename RT>
298 , value_is_initialized(false)
301 inline reference_type
305 value_is_initialized,
307 "You cannot read the return value of a thread or task "
308 "if that value has not been set. This happens, for example, if "
309 "a task or thread threw an exception."));
332 value_is_initialized =
true;
388 template <
typename T>
407 template <
typename T>
410 static std::reference_wrapper<T>
425 template <
typename RT,
typename Function>
427 (std::invocable<Function> &&
428 std::convertible_to<std::invoke_result_t<Function>, RT>))
444 template <
typename Function>
482 template <
typename RT =
void>
497 Task(
const std::function<RT()> &function_object)
501#ifdef DEAL_II_WITH_TBB
506 std::unique_ptr<std::promise<RT>> promise =
507 std::make_unique<std::promise<RT>>();
509 std::make_shared<TaskData>(std::move(promise->get_future()));
549 std::shared_ptr<std::promise<RT>>(std::move(promise))]() {
559 promise->set_exception(std::current_exception());
588 std::async(std::launch::async | std::launch::deferred,
604 std::promise<RT> promise;
605 task_data = std::make_shared<TaskData>(promise.get_future());
615 promise.set_exception(std::current_exception());
827 "The current object is not associated with a task that "
828 "can be joined. It may have been detached, or you "
829 "may have already joined it in the past.");
850#ifdef DEAL_II_WITH_TBB
851 ,
task_group(std::make_unique<tbb::task_group>())
937 std::lock_guard<std::mutex> lock(
mutex);
942#ifdef DEAL_II_WITH_TBB
1047#ifdef DEAL_II_WITH_TBB
1057 friend class Task<RT>;
1089 template <
typename RT>
1175 template <
typename FunctionObjectType>
1177 inline auto
new_task(FunctionObjectType function_object)
1178 ->
Task<decltype(function_object())>
1180 using return_type =
decltype(function_object());
1182 return new_task(std::function<return_type()>(function_object));
1193 template <
typename RT,
typename... Args>
1199 [dummy, fun_ptr]() -> RT {
return std::apply(fun_ptr, dummy); });
1245 typename FunctionObject,
1247 typename = std::enable_if_t<std::is_invocable_v<FunctionObject, Args...>>,
1248 typename = std::enable_if_t<std::is_function_v<FunctionObject> ==
false>,
1250 std::enable_if_t<std::is_member_pointer_v<FunctionObject> ==
false>,
1251 typename = std::enable_if_t<std::is_pointer_v<FunctionObject> ==
false>>
1252 inline Task<std::invoke_result_t<FunctionObject, Args...>>
1255 using RT = std::invoke_result_t<FunctionObject, Args...>;
1256 auto dummy = std::make_tuple(std::forward<Args>(args)...);
1257 return new_task([dummy, fun]() -> RT {
return std::apply(fun, dummy); });
1268 template <
typename RT,
typename C,
typename... Args>
1272 std_cxx20::type_identity_t<Args>... args)
1275 return new_task(std::function<RT()>(std::bind(
1285 template <
typename RT,
typename C,
typename... Args>
1289 std_cxx20::type_identity_t<Args>... args)
1292 return new_task(std::function<RT()>(std::bind(
1311 template <
typename RT =
void>
1336 return tasks.size();
1356 std::vector<RT> results;
1357 results.reserve(
size());
1358 for (
auto &t :
tasks)
1359 results.emplace_back(std::move(t.return_value()));
1373 for (
auto &t :
tasks)
static void initialize_multithreading()
static unsigned int n_threads()
TaskGroup & operator+=(const Task< RT > &t)
std::vector< RT > return_values()
std::list< Task< RT > > tasks
TaskData(std::future< RT > &&future) noexcept
TaskData(const TaskData &)=delete
TaskData & operator=(const TaskData &)=delete
std::atomic< bool > task_has_finished
internal::return_value< RT > returned_object
std::unique_ptr< tbb::task_group > task_group
TaskData & operator=(TaskData &&)=delete
TaskData(TaskData &&)=delete
internal::return_value< RT >::reference_type get()
Task(Task &&other) noexcept=default
std::shared_ptr< TaskData > task_data
internal::return_value< RT >::reference_type return_value()
Task & operator=(Task &&other) noexcept=default
Task(const Task &other)=default
Task(const std::function< RT()> &function_object)
Task & operator=(const Task &other)=default
#define DEAL_II_NAMESPACE_OPEN
#define DEAL_II_CXX20_REQUIRES(condition)
#define DEAL_II_NAMESPACE_CLOSE
static ::ExceptionBase & ExcNoTask()
#define Assert(cond, exc)
#define DeclExceptionMsg(Exception, defaulttext)
static ::ExceptionBase & ExcMessage(std::string arg1)
#define AssertThrow(cond, exc)
std::vector< std::pair< ForwardIterator, ForwardIterator > > split_range(const ForwardIterator &begin, const ForwardIterator &end, const unsigned int n_intervals)
Task< RT > new_task(const std::function< RT()> &function)
std::vector< std::pair< unsigned int, unsigned int > > split_interval(const unsigned int begin, const unsigned int end, const unsigned int n_intervals)
void handle_unknown_exception()
std::promise< RT > & promise
void evaluate_and_set_promise(Function &function, std::promise< void > &promise)
void handle_std_exception(const std::exception &exc)
const Iterator const std_cxx20::type_identity_t< Iterator > & end
typename type_identity< T >::type type_identity_t
static std::reference_wrapper< T > act(T &t)
reference_type get() const
bool value_is_initialized
void set_from(std::future< RT & > &v)
void set_from(std::future< void > &)
bool value_is_initialized
void set_from(std::future< RT > &v)