code: def bfgs(inv_H, delta_w, delta_grad, epsilon=1e-7):
      """
      It can suffer from round-off error and inaccurate line searches.
      """
      n_parameters = int(inv_H.shape[0])
  
      I = tf.eye(n_parameters)
      rho = safe_reciprocal(dot(delta_grad, delta_w), epsilon)
  
      X = I - outer(delta_w, delta_grad) * rho
      X_T = tf.transpose(X)
      Z = rho * outer(delta_w, delta_w)
  
      return tf.matmul(X, tf.matmul(inv_H, X_T)) + Z
  
file_path: neupy/neupy/algorithms/gd/quasi_newton.py
imports: import tensorflow
  from neupy.core.config import Configurable
  from neupy.core.properties import ChoiceProperty, NumberProperty, WithdrawProperty, IntProperty
  from neupy.utils.tf_utils import setup_parameter_updates
  from neupy.algorithms.minsearch.wolfe import line_search
  from neupy.utils import asfloat, dot, outer, as_tuple, function_name_scope, make_single_vector
  from .base import BaseOptimizer
label_desc: Use image node_id 3 for calling a global function with example usage: bfgs(inv_H, delta_w, delta_grad, epsilon) and returns: unknown