REPRESENTATION COMPRESSION AND GENERALIZATION IN DEEP NEURAL NETWORKS
Authors: Ravid Shwartz-Ziv, Amichai Painsky, Naftali Tishby
Keywords: Deep neural network, information theory, training dynamics
TL;DR: Introduce an information theoretic viewpoint on the behavior of deep networks optimization processes and their generalization abilities
Abstract: Understanding the groundbreaking performance of Deep Neural Networks is one
of the greatest challenges to the scientific community today. In this work, we
introduce an information theoretic viewpoint on the behavior of deep networks
optimization processes and their generalization abilities. By studying the Information
Plane, the plane of the mutual information between the input variable and
the desired label, for each hidden layer. Specifically, we show that the training of
the network is characterized by a rapid increase in the mutual information (MI)
between the layers and the target label, followed by a longer decrease in the MI
between the layers and the input variable. Further, we explicitly show that these
two fundamental information-theoretic quantities correspond to the generalization
error of the network, as a result of introducing a new generalization bound that is
exponential in the representation compression. The analysis focuses on typical
patterns of large-scale problems. For this purpose, we introduce a novel analytic
bound on the mutual information between consecutive layers in the network.
An important consequence of our analysis is a super-linear boost in training time
with the number of non-degenerate hidden layers, demonstrating the computational
benefit of the hidden layers.