OMPHelper.h

// BSD 3-Clause License
//
// Copyright (c) 2019, Bailin Deng
// All rights reserved.
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// modification, are permitted provided that the following conditions are met:
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#ifndef OMPHELPER_H_
#define OMPHELPER_H_

#ifdef USE_OPENMP
#include <omp.h>
#ifdef USE_MSVC
#define OMP_PARALLEL __pragma(omp parallel)
#define OMP_FOR __pragma(omp for)
#define OMP_SINGLE __pragma(omp single)
#define OMP_SECTIONS __pragma(omp sections)
#define OMP_SECTION __pragma(omp section)
#define OMP_SECTIONS_NOWAIT __pragma(omp sections nowait)
#else
#define OMP_PARALLEL _Pragma("omp parallel")
#define OMP_FOR _Pragma("omp for")
#define OMP_SINGLE _Pragma("omp single")
#define OMP_SECTIONS _Pragma("omp sections")
#define OMP_SECTION _Pragma("omp section")
#define OMP_SECTIONS_NOWAIT _Pragma("omp sections nowait")
#endif

#else
#include <ctime>
#define OMP_PARALLEL
#define OMP_FOR
#define OMP_SINGLE
#define OMP_SECTIONS
#define OMP_SECTION
#define OMP_SECTIONS_NOWAIT
#endif

#include <cassert>
#include <vector>

class Timer {
 public:

  typedef int EventID;

  EventID get_time() {
    EventID id = time_values_.size();

#ifdef USE_OPENMP
    time_values_.push_back(omp_get_wtime());
#else
    time_values_.push_back(clock());
#endif

    return id;
  }

  double elapsed_time(EventID event1, EventID event2) {
    assert(event1 >= 0 && event1 < static_cast<EventID>(time_values_.size()));
    assert(event2 >= 0 && event2 < static_cast<EventID>(time_values_.size()));

#ifdef USE_OPENMP
    return time_values_[event2] - time_values_[event1];
#else
    return double(time_values_[event2] - time_values_[event1]) / CLOCKS_PER_SEC;
#endif
  }

  void reset() {
    time_values_.clear();
  }

 private:
#ifdef USE_OPENMP
  std::vector<double> time_values_;
#else
  std::vector<clock_t> time_values_;
#endif
};

#endif /* OMPHELPER_H_ */