A robust estimator of mutual information for deep learning interpretability. Issue 2 (1st June 2023)

• Record Type: Journal Article
• Authors: Piras, Davide; Peiris, Hiranya V; Pontzen, Andrew; Lucie-Smith, Luisa; Guo, Ningyuan; Nord, Brian
• Is Part Of: Machine learning: science and technology. Volume 4:Issue 2(2023)
• Publication Date: 2023-06-01
• Subjects: deep learning -- mutual information -- interpretability -- representation learning; 006.31
• DOI: 10.1088/2632-2153/acc444
• Languages: English
• ISSNs: 2632-2153

Abstract

Abstract: We develop the use of mutual information (MI), a well-established metric in information theory, to interpret the inner workings of deep learning (DL) models. To accurately estimate MI from a finite number of samples, we present GMM-MI (pronounced 'Jimmie'), an algorithm based on Gaussian mixture models that can be applied to both discrete and continuous settings. GMM-MI is computationally efficient, robust to the choice of hyperparameters and provides the uncertainty on the MI estimate due to the finite sample size. We extensively validate GMM-MI on toy data for which the ground truth MI is known, comparing its performance against established MI estimators. We then demonstrate the use of our MI estimator in the context of representation learning, working with synthetic data and physical datasets describing highly non-linear processes. We train DL models to encode high-dimensional data within a meaningful compressed (latent) representation, and use GMM-MI to quantify both the level of disentanglement between the latent variables, and their association with relevant physical quantities, thus unlocking the interpretability of the latent representation. We make GMM-MI publicly available in this GitHub repository.