def _prepare_args_with_initial_vertex(objective_function,
                                      initial_vertex,
                                      step_sizes,
                                      objective_at_initial_vertex,
                                      batch_evaluate_objective):
  """"""
  dim = tf.size(input=initial_vertex)
  num_vertices = dim + 1
  unit_vectors_along_axes = tf.reshape(
      tf.eye(dim, dim, dtype=initial_vertex.dtype.base_dtype),
      tf.concat([[dim], tf.shape(input=initial_vertex)], axis=0))

  # If step_sizes does not broadcast to initial_vertex, the multiplication
  # in the second term will fail.
  simplex_face = initial_vertex + step_sizes * unit_vectors_along_axes
  simplex = tf.concat([tf.expand_dims(initial_vertex, axis=0),
                       simplex_face], axis=0)
  num_evaluations = 0
  # Evaluate the objective function at the simplex vertices.
  if objective_at_initial_vertex is None:
    objective_at_initial_vertex = objective_function(initial_vertex)
    num_evaluations += 1

  objective_at_simplex_face, num_evals = _evaluate_objective_multiple(
      objective_function, simplex_face, batch_evaluate_objective)
  num_evaluations += num_evals

  objective_at_simplex = tf.concat(
      [
          tf.expand_dims(objective_at_initial_vertex, axis=0),
          objective_at_simplex_face
      ], axis=0)

  return (dim,
          num_vertices,
          simplex,
          objective_at_simplex,
          num_evaluations)