Fixed-Mean Gaussian Processes for Post-hoc Bayesian Deep Learning

Fuente: arXiv
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Main Authors: Ortega, Luis A., Rodríguez-Santana, Simón, Hernández-Lobato, Daniel
Format: Preprint
Published: 2024
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author Ortega, Luis A.
Rodríguez-Santana, Simón
Hernández-Lobato, Daniel
author_facet Ortega, Luis A.
Rodríguez-Santana, Simón
Hernández-Lobato, Daniel
contents Recently, there has been an increasing interest in performing post-hoc uncertainty estimation about the predictions of pre-trained deep neural networks (DNNs). Given a pre-trained DNN via back-propagation, these methods enhance the original network by adding output confidence measures, such as error bars, without compromising its initial accuracy. In this context, we introduce a novel family of sparse variational Gaussian processes (GPs), where the posterior mean is fixed to any continuous function when using a universal kernel. Specifically, we fix the mean of this GP to the output of the pre-trained DNN, allowing our approach to effectively fit the GP's predictive variances to estimate the DNN prediction uncertainty. Our approach leverages variational inference (VI) for efficient stochastic optimization, with training costs that remain independent of the number of training points, scaling efficiently to large datasets such as ImageNet. The proposed method, called fixed-mean GP (FMGP), is architecture-agnostic, relying solely on the pre-trained model's outputs to adjust the predictive variances. Experimental results demonstrate that FMGP improves both uncertainty estimation and computational efficiency when compared to state-of-the-art methods for DNN post-hoc Bayesian inference.
format Preprint
id arxiv_https___arxiv_org_abs_2412_04177
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fixed-Mean Gaussian Processes for Post-hoc Bayesian Deep Learning
Ortega, Luis A.
Rodríguez-Santana, Simón
Hernández-Lobato, Daniel
Machine Learning
Recently, there has been an increasing interest in performing post-hoc uncertainty estimation about the predictions of pre-trained deep neural networks (DNNs). Given a pre-trained DNN via back-propagation, these methods enhance the original network by adding output confidence measures, such as error bars, without compromising its initial accuracy. In this context, we introduce a novel family of sparse variational Gaussian processes (GPs), where the posterior mean is fixed to any continuous function when using a universal kernel. Specifically, we fix the mean of this GP to the output of the pre-trained DNN, allowing our approach to effectively fit the GP's predictive variances to estimate the DNN prediction uncertainty. Our approach leverages variational inference (VI) for efficient stochastic optimization, with training costs that remain independent of the number of training points, scaling efficiently to large datasets such as ImageNet. The proposed method, called fixed-mean GP (FMGP), is architecture-agnostic, relying solely on the pre-trained model's outputs to adjust the predictive variances. Experimental results demonstrate that FMGP improves both uncertainty estimation and computational efficiency when compared to state-of-the-art methods for DNN post-hoc Bayesian inference.
title Fixed-Mean Gaussian Processes for Post-hoc Bayesian Deep Learning
topic Machine Learning
url https://arxiv.org/abs/2412.04177