ParallelRunner.h

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2017 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#pragma once
 
#include "MantidParallel/Communicator.h"
#include "MantidParallel/DllConfig.h"
 
#include <memory>
 
#include <functional>
#include <thread>
 
namespace ParallelTestHelpers {
 
class ParallelRunner {
public:
  ParallelRunner();
  ParallelRunner(const int threads);
 
  int size() const;
 
  template <class Function, class... Args> void runSerial(Function &&f, Args &&...args);
  template <class Function, class... Args> void runParallel(Function &&f, Args &&...args);
 
private:
  std::shared_ptr<Mantid::Parallel::detail::ThreadingBackend> m_backend;
  std::shared_ptr<Mantid::Parallel::detail::ThreadingBackend> m_serialBackend;
};
 
template <class Function, class... Args> void ParallelRunner::runSerial(Function &&f, Args &&...args) {
  f(Mantid::Parallel::Communicator(m_serialBackend, 0), std::forward<Args>(args)...);
}
 
template <class Function, class... Args> void ParallelRunner::runParallel(Function &&f, Args &&...args) {
  if (!m_backend) {
    Mantid::Parallel::Communicator comm;
    f(comm, std::forward<Args>(args)...);
  } else {
    std::vector<std::thread> threads;
    for (int t = 0; t < m_backend->size(); ++t) {
      Mantid::Parallel::Communicator comm(m_backend, t);
      threads.emplace_back(std::forward<Function>(f), comm, std::forward<Args>(args)...);
    }
    for (auto &t : threads) {
      t.join();
    }
  }
}
 
template <class... Args> void runParallel(Args &&...args) {
  ParallelRunner runner;
  runner.runParallel(std::forward<Args>(args)...);
}
 
} // namespace ParallelTestHelpers