macros for time evaluation

timer.h

#include <chrono>

/*! \brief Timer */
class Timer {
  using Clock = std::chrono::high_resolution_clock;
public:
  /*! \brief start or restart timer */
  inline void Tic() {
    start_ = Clock::now();
  }
  /*! \brief stop timer */
  inline void Toc() {
    end_ = Clock::now();
  }
  /*! \brief return time in ms */
  inline double Elasped() {
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end_ - start_);
    return duration.count();
  }

private:
  Clock::time_point start_, end_;
};