Function parallelMap

src/thread_utils.h:42–72

 */
template <class It, class Callable>
void parallelMap(It begin, It end, Callable callable, std::size_t nThreads)
{
  std::mutex m;
  std::vector<std::thread> threads(nThreads);

  // Create the thread:
  //  - The mutex is only used to fetch/increment the iterator.
  //  - The callable is copied in each thread to avoid conflicts.
  for (auto& thread : threads) {
    thread = startSafeThread([&m, &begin, end, callable]() {
      while (true) {
        decltype(begin) it;
        {
          std::scoped_lock lock(m);
          if (begin == end) {
            break;
          }
          it = begin++;
        }
        if (it != end) {
          std::invoke(callable, *it);
        }
      }
    });
  }

  // Join everything:
  for (auto& t : threads) {
    t.join();
  }
}

}  // namespace MOShared