8.3.1.4. Lennard-Jones
**********************

class LennardJonesParameters(settings=None, eps_initial=0.0003, eps_range=(0.0001, 0.001), eps_is_variable=True, rmin_initial=3.0, rmin_range=(0.5, 10.0), rmin_is_variable=True)

   A class representing the parameterization of a Lennard-Jones
   potential engine in AMS.

   __init__(settings=None, eps_initial=0.0003, eps_range=(0.0001, 0.001), eps_is_variable=True, rmin_initial=3.0, rmin_range=(0.5, 10.0), rmin_is_variable=True)

      Constructs a new parameterization for a Lennard-Jones engine.

      Parameters:
         * **settings** -- an optional Settings instance used for the
           engines returned by this class.

         * **eps_initial** -- the initial value for the potential
           depth \epsilon

         * **eps_range** -- a tuple (min, max) for the allowed range
           of the potential depth \epsilon

         * **eps_variable** -- whether the potential depth \epsilon is
           a variable parameter

         * **rmin_initial** -- the initial value for the equilibrium
           distance r_\text{min}

         * **rmin_range** -- a tuple (min, max) for the allowed range
           of the equilibrium distance r_\text{min}

         * **rmin_variable** -- whether the equilibrium distance
           r_\text{min} is a variable parameter

   get_engine(parameters=None, path=None, write=False)

      Given a set of parameters returns a ready-to-run LennardJones
      Engine.

      Note that len(params) should be equal to
      len(self.num_parameters).

      Note: "path" and "write" are ignored for this engine, since the
      parameters are included in the engine block.

      Returns:
         an Engine instance for the given parameters

   write(path, parameters=None)

      Writes the parameterization to disk.

      Since the AMS Lennard-Jones does not use parameter files, the
      file written is just a text file containing the Lennard-Jones
      engine block to include in the input file.
