Revisiting Natural Gradient for Deep Networks
Authors: Razvan Pascanu, Yoshua Bengio

Abstract: The aim of this paper is three-fold. First we show that Hessian-Free (Martens, 2010) and Krylov Subspace Descent (Vinyals and Povey, 2012) can be described as implementations of natural gradient descent due to their use of the extended Gauss-Newton approximation of the Hessian. Secondly we re-derive natural gradient from basic principles, contrasting the difference between two versions of the algorithm found in the neural network literature, as well as highlighting a few differences between natural gradient and typical second order methods. Lastly we show empirically that natural gradient can be robust to overfitting and particularly it can be robust to the order in which the training data is presented to the model.

Decision: submitted, no decision