cessors
  so will not get same answers independent of # of processors
for replace and langevin styles, RNG states are not saved in restart file,
  so cannot do an exact restart
for langevin style, damping parameter means small value -> less damping
for nose/hoover style, frequency constant is like an inverse 
  &quot;piston&quot; mass which determines how rapidly the temperature 
  fluctuates in response to a restoring force, large frequency -&gt; 
  small mass -&gt; rapid fluctations
for nose/hoover style,