WrapOpenMP.h

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#pragma once
 
#if defined(AUTOPAS_USE_OPENMP)
#include <omp.h>
 
#include <cstddef>  // for size_t
#include <vector>
#else
#include "ExceptionHandler.h"
#endif
 
namespace autopas {
 
#if defined(AUTOPAS_USE_OPENMP)
 
#define AUTOPAS_DO_PRAGMA(x) _Pragma(#x)
 
#define AUTOPAS_OPENMP(args) AUTOPAS_DO_PRAGMA(omp args)
 
inline int autopas_get_thread_num() { return omp_get_thread_num(); }
 
inline int autopas_get_num_threads() { return omp_get_num_threads(); }
 
inline int autopas_get_max_threads() { return omp_get_max_threads(); }
 
inline void autopas_set_num_threads(int n) { omp_set_num_threads(n); }
 
class AutoPasLock {
 public:
  AutoPasLock() { omp_init_lock(&_lock); }
 
  AutoPasLock(AutoPasLock &&) noexcept { omp_init_lock(&_lock); }
 
  AutoPasLock(const AutoPasLock &) { omp_init_lock(&_lock); }
 
  AutoPasLock &operator=(AutoPasLock) = delete;
 
  ~AutoPasLock() { omp_destroy_lock(&_lock); }
 
  void lock() { omp_set_lock(&_lock); }
 
  void unlock() { omp_unset_lock(&_lock); }
 
 private:
  omp_lock_t _lock;
};
 
// reduction for merging vectors: {1,2} + {2,3} -> {1,2,2,3}
#pragma omp declare reduction(vecMerge : std::vector<size_t> : omp_out.insert(omp_out.end(), omp_in.begin(), omp_in.end()))
#pragma omp declare reduction(vecMerge : std::vector<double> : omp_out.insert(omp_out.end(), omp_in.begin(), omp_in.end()))
 
#else
 
#define AUTOPAS_OPENMP(args)
 
inline int autopas_get_thread_num() { return 0; }
 
inline int autopas_get_num_threads() { return 1; }
 
inline int autopas_get_max_threads() { return 1; }
 
inline void autopas_set_num_threads(int /* n */) {}
 
class AutoPasLock {
 public:
  AutoPasLock() { _locked = false; }
 
  AutoPasLock(AutoPasLock &&) noexcept { _locked = false; }
 
  AutoPasLock(AutoPasLock &) { _locked = false; }
 
  AutoPasLock &operator=(AutoPasLock) = delete;
 
  ~AutoPasLock() {
    if (_locked) {
      utils::ExceptionHandler::exception("AutoPasLocked destroyed in locked state.");
    }
  }
 
  void lock() {
    if (_locked) {
      utils::ExceptionHandler::exception("Tried to acquire a locked lock.");
    }
    _locked = true;
  }
 
  void unlock() {
    if (not _locked) {
      utils::ExceptionHandler::exception("Tried to release an unlocked lock.");
    }
    _locked = false;
  }
 
 private:
  // true if locked, false if unlocked
  bool _locked;
};
 
#endif
 
// These properties are needed because we use AutoPasLock in vectors on which we call resize().
static_assert(std::is_default_constructible_v<AutoPasLock>, "AutoPasLock needs to be default constructible!");
static_assert(std::is_move_constructible_v<AutoPasLock>, "AutoPasLock needs to be move constructible!");
 
}  // namespace autopas