{

  t_start = t_stop = t_new;

}

/* ---------------------------------------------------------------------- */

void FixLangevin::reset_dt()

{

  for (int i = 1; i <= atom->ntypes; i++) {

    gfactor2[i] = sqrt(atom->mass[i]) * 

      sqrt(24.0*force->boltz/t_period/update->dt/force->mvv2e) / force->ftm2v;

    gfactor2[i] *= 1.0/sqrt(ratio[i]);

  }

}

  void post_force(int);

  void post_force_respa(int, int, int);

  void reset_target(double);

  void reset_dt();

 private:

  double t_start,t_stop,t_period;