A Geometric Modeling of Occam's Razor in Deep Learning
This work addresses a foundational theoretical problem in machine learning, offering insights into model selection for deep learning, though it is incremental in building on existing geometric frameworks.
The paper tackles the problem of why deep neural networks perform well despite high parameter complexity by proposing a geometric information-theoretic approach, resulting in derived complexity measures that explain their good performance.
Why do deep neural networks (DNNs) benefit from very high dimensional parameter spaces? Their huge parameter complexities vs stunning performance in practice is all the more intriguing and not explainable using the standard theory of model selection for regular models. In this work, we propose a geometrically flavored information-theoretic approach to study this phenomenon. With the belief that simplicity is linked to better generalization, as grounded in the theory of minimum description length, the objective of our analysis is to examine and bound the complexity of DNNs. We introduce the locally varying dimensionality of the parameter space of neural network models by considering the number of significant dimensions of the Fisher information matrix, and model the parameter space as a manifold using the framework of singular semi-Riemannian geometry. We derive model complexity measures which yield short description lengths for deep neural network models based on their singularity analysis thus explaining the good performance of DNNs despite their large number of parameters.