delta_v = dynamics_.back ()->volume_ - dynamics_[0]->volume_;
Moment start = dynamics_[0]->get_column ()->when ();
Real total_t = moment_to_real (dynamics_.back ()->get_column ()->when () - start);
delta_v = dynamics_.back ()->volume_ - dynamics_[0]->volume_;
Moment start = dynamics_[0]->get_column ()->when ();
Real total_t = moment_to_real (dynamics_.back ()->get_column ()->when () - start);