docs/ParallelSort.html
Taskflow provides template functions for constructing tasks to sort ranges of items in parallel.
You need to include the header file, taskflow/algorithm/sort.hpp, for creating a parallel-sort task.
#include \<taskflow/algorithm/sort.hpp\>
The task created by tf::Taskflow::sort(B first, E last) performs parallel sort to rank a range of elements specified by [first, last) in increasing order. The given iterators must be random-accessible. The following example creates a task to sort a data vector in increasing order.
tf::Taskflow taskflow;tf::Executor executor;std::vector\<int\> data = {1, 4, 9, 2, 3, 11, -8};tf::Task sort = taskflow.sort(data.begin(), data.end());executor.run(taskflow).wait();assert(std::is\_sorted(data.begin(), data.end()));
tf::Taskflow::sort(B first, E last, C cmp) is an overload of parallel sort that allows users to specify a custom comparator. The following example sorts a data vector in decreasing order.
tf::Taskflow taskflow;tf::Executor executor;std::vector\<int\> data = {1, 4, 9, 2, 3, 11, -8};tf::Task sort = taskflow.sort(data.begin(), data.end(), [](int a, int b) { return a \> b; });executor.run(taskflow).wait();assert(std::is\_sorted(data.begin(), data.end(), std::greater\<int\>{}));
The iterators taken by tf::Taskflow::sort are templated. You can use std::reference_wrapper to enable stateful data passing between the sort task and others. The following example creates a task init to initialize the data vector and a task sort to sort the data in parallel after init finishes.
tf::Taskflow taskflow;tf::Executor executor;std::vector\<int\> data;std::vector\<int\>::iterator first, last;tf::Task init = taskflow.emplace(&{ data= {1, 4, 9, 2, 3, 11, -8}; first = data.begin();last= data.end();});tf::Task sort = taskflow.sort(std::ref(first), std::ref(last), [] (int l, int r) { return l \< r; });init.precede(sort);executor.run(taskflow).wait();assert(std::is\_sorted(data.begin(), data.end()));