def _resolve_parameters(dim,
                        reflection,
                        expansion,
                        contraction,
                        shrinkage,
                        dtype):
  """Applies the [Gao and Han][3] presciption to the unspecified parameters."""
  dim = tf.cast(dim, dtype=dtype)
  reflection = 1. if reflection is None else reflection
  expansion = (1. + 2. / dim) if expansion is None else expansion
  contraction = (0.75 - 1. / (2 * dim)) if contraction is None else contraction
  shrinkage = (1. - 1. / dim) if shrinkage is None else shrinkage
  return reflection, expansion, contraction, shrinkage