Author: Brandon S Runnels (brunnels@uccs.edu),
        The University of Colorado Colorado Springs
Date: 2019-06-04
Version: 001

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*                       Summary of input variables                           *
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In this Test Driver (TD), the user specifies the following variables through
stdin using a Jinja template file named 'pipeline.stdin.tpl' contained in the
directory of a Test which uses this TD (the sequence in which they are
specified must be the same as below, with 'modelname' being the first):

modelname: string
  Contains the extended-id of a valid KIM Model.  This can be specified by '@<
  MODELNAME >@' in pipeline.stdin.tpl.  When the pipeline mates a Model with
  the Test, it will automatically replace '@< MODELNAME >@' with the Model's
  extended-ID.

a1: 3D integer-valued vector
  The miller indices corresponding to the vector that is initially in the GB
  (along the x direction)

a2: 3D integer-valued vector
  The miller indices corresponding to the vector that is initially normal to
  the GB (along the y direction)

a3: 3D integer-valued vector
  The miller indices corresponding to the tilt direction (along the z
  direction)

  Note: a1, a2, a3 must be mutually orthogonal and must obey the
  right hand rule. Normality is not enforced.

species: string
  The name of the material

theta_min: double
  The initial tilt angle (in degrees)

theta_max: double
  The final tilt angle (in degrees)

max_denominator: int
  The maximum width (in number of latice spacings) of a repeating unit cell.
  The choice of this variable determines the number of GB orientations that
  will be considered.

short_name: string
  The name of the crystal structure: should be fcc, bcc, or sc

cutoff_distance: double
  The threshold for initially deleting atomns. Units are in terms of lattice
  spacings, for instance, a value of 0.5 would delete atoms that are closer
  than 0.5*a.

x_repeat: integer
  Number of repeating cells in the x direction

z_repeat: integer
  Number of repeating cells in the z direction

min_cell_height: float
  Minimum height of the unit cell (direction normal to interface). The number
  of repeating cells in the y direction is determined based on this value.

offset_top: 3D float vector
  Initial offset of the top crystal

offset_bottom: 3D float vector
  Initial offset of the bottom crystal

a: double
  The lattice constant

cohesive_energy: float
  The cohesive energy of the lattice

mass: double
  The molar mass (in g/mol) of the element specified by 'element', e.g. 39.948
  for Argon.