tensorflow_probability/python/optimizer/nelder_mead.py
def _outside_contraction_fn(objective_function,
                            simplex,
                            objective_values,
                            face_centroid,
                            best_index,
                            worst_index,
                            reflected,
                            objective_at_reflected,
                            contraction,
                            shrinkage,
                            batch_evaluate_objective):
  """Creates the condition function pair for an outside contraction."""
  def _contraction():
    """Performs a contraction."""
    contracted = face_centroid + contraction * (reflected - face_centroid)
    objective_at_contracted = objective_function(contracted)
    is_contracted_acceptable = objective_at_contracted <= objective_at_reflected
    def _accept_contraction():
      next_simplex = _replace_at_index(simplex, worst_index, contracted)
      objective_at_next_simplex = _replace_at_index(
          objective_values,
          worst_index,
          objective_at_contracted)
      return (False,
              next_simplex,
              objective_at_next_simplex,
              1)

    def _reject_contraction():
      return _shrink_towards_best(objective_function,
                                  simplex,
                                  best_index,
                                  shrinkage,
                                  batch_evaluate_objective)

    return prefer_static.cond(is_contracted_acceptable,
                              _accept_contraction,
                              _reject_contraction)
  return _contraction
def _outside_contraction_fn(objective_function,
                            simplex,
                            objective_values,
                            face_centroid,
                            best_index,
                            worst_index,
                            reflected,
                            objective_at_reflected,
                            contraction,
                            shrinkage,
                            batch_evaluate_objective):
  """Creates the condition function pair for an outside contraction."""
  def _contraction():
    """Performs a contraction."""
    contracted = face_centroid + contraction * (reflected - face_centroid)
    objective_at_contracted = objective_function(contracted)
    is_contracted_acceptable = objective_at_contracted <= objective_at_reflected
    def _accept_contraction():
      next_simplex = _replace_at_index(simplex, worst_index, contracted)
      objective_at_next_simplex = _replace_at_index(
          objective_values,
          worst_index,
          objective_at_contracted)
      return (False,
              next_simplex,
              objective_at_next_simplex,
              1)

    def _reject_contraction():
      return _shrink_towards_best(objective_function,
                                  simplex,
                                  best_index,
                                  shrinkage,
                                  batch_evaluate_objective)

    return prefer_static.cond(is_contracted_acceptable,
                              _accept_contraction,
                              _reject_contraction)
  return _contraction
Creates the condition function pair for an outside contraction.