A Mutual Information Lower Bound for Multimodal Regression Active Learning

Fuente: arXiv
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Autori principali: Guilhoto, Leonardo Ferreira, Kaushal, Akshat, Perdikaris, Paris
Natura: Preprint
Pubblicazione: 2026
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author Guilhoto, Leonardo Ferreira
Kaushal, Akshat
Perdikaris, Paris
author_facet Guilhoto, Leonardo Ferreira
Kaushal, Akshat
Perdikaris, Paris
contents Active learning for continuous regression has lacked an acquisition function that targets epistemic uncertainty when the predictive distribution is multimodal: variance misses modal disagreement, and information-theoretic targets like BALD are designed for discrete outputs. We introduce a Two-Index framework that makes this separation explicit: one stochastic index selects among competing model hypotheses (epistemic source), while a second governs within-hypothesis randomness (aleatoric source). An entropy decomposition within the framework identifies the mutual information between the output and the epistemic index as a principled acquisition objective, and we prove this quantity vanishes as the model is trained on growing datasets, confirming that it captures exactly the uncertainty data can resolve. Because this mutual information is intractable for continuous outputs, we derive the Mutual Information Lower Bound (MI-LB) acquisition function, a closed-form approximation for Mixture Density Network ensembles. On benchmarks featuring multimodal systems, MI-LB matches or beats every baseline evaluated and is the only method to do so consistently -- geometric and Fisher-based baselines compete only when the input space already encodes the multimodality, and collapse otherwise.
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id arxiv_https___arxiv_org_abs_2605_14917
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Mutual Information Lower Bound for Multimodal Regression Active Learning
Guilhoto, Leonardo Ferreira
Kaushal, Akshat
Perdikaris, Paris
Machine Learning
Computational Engineering, Finance, and Science
Information Theory
68T37 (Primary), 68T05 (Secondary)
G.3; J.2; I.2; E.m
Active learning for continuous regression has lacked an acquisition function that targets epistemic uncertainty when the predictive distribution is multimodal: variance misses modal disagreement, and information-theoretic targets like BALD are designed for discrete outputs. We introduce a Two-Index framework that makes this separation explicit: one stochastic index selects among competing model hypotheses (epistemic source), while a second governs within-hypothesis randomness (aleatoric source). An entropy decomposition within the framework identifies the mutual information between the output and the epistemic index as a principled acquisition objective, and we prove this quantity vanishes as the model is trained on growing datasets, confirming that it captures exactly the uncertainty data can resolve. Because this mutual information is intractable for continuous outputs, we derive the Mutual Information Lower Bound (MI-LB) acquisition function, a closed-form approximation for Mixture Density Network ensembles. On benchmarks featuring multimodal systems, MI-LB matches or beats every baseline evaluated and is the only method to do so consistently -- geometric and Fisher-based baselines compete only when the input space already encodes the multimodality, and collapse otherwise.
title A Mutual Information Lower Bound for Multimodal Regression Active Learning
topic Machine Learning
Computational Engineering, Finance, and Science
Information Theory
68T37 (Primary), 68T05 (Secondary)
G.3; J.2; I.2; E.m
url https://arxiv.org/abs/2605.14917