led by the fractional
  amount (0.0 to 1.0), e.g. a value of 0.5 means set the velocities
  to halfway between the current and target temperature
for rescale style, it can be used as a coarse temperature rescaler,
  for example "rescale 200.0 300.0 100 10.0 1.0" will ramp the temperature
  up during the simulation, resetting it to the target temperature as needed
for rescale style, it can be used to create an instantaneous
  drag force that slowly rescales the temperature without oscillation,
  for example 