Martingale Posterior Neural Networks for Fast Sequential Decision Making

Fuente: arXiv
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Auteurs principaux: Duran-Martin, Gerardo, Sánchez-Betancourt, Leandro, Cartea, Álvaro, Murphy, Kevin
Format: Preprint
Publié: 2025
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author Duran-Martin, Gerardo
Sánchez-Betancourt, Leandro
Cartea, Álvaro
Murphy, Kevin
author_facet Duran-Martin, Gerardo
Sánchez-Betancourt, Leandro
Cartea, Álvaro
Murphy, Kevin
contents We introduce scalable algorithms for online learning of neural network parameters and Bayesian sequential decision making. Unlike classical Bayesian neural networks, which induce predictive uncertainty through a posterior over model parameters, our methods adopt a predictive-first perspective based on martingale posteriors. In particular, we work directly with the one-step-ahead posterior predictive, which we parameterize with a neural network and update sequentially with incoming observations. This decouples Bayesian decision-making from parameter-space inference: we sample from the posterior predictive for decision making, and update the parameters of the posterior predictive via fast, frequentist Kalman-filter-like recursions. Our algorithms operate in a fully online, replay-free setting, providing principled uncertainty quantification without costly posterior sampling. Empirically, they achieve competitive performance-speed trade-offs in non-stationary contextual bandits and Bayesian optimization, offering 10-100 times faster inference than classical Thompson sampling while maintaining comparable or superior decision performance.
format Preprint
id arxiv_https___arxiv_org_abs_2506_11898
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Martingale Posterior Neural Networks for Fast Sequential Decision Making
Duran-Martin, Gerardo
Sánchez-Betancourt, Leandro
Cartea, Álvaro
Murphy, Kevin
Machine Learning
We introduce scalable algorithms for online learning of neural network parameters and Bayesian sequential decision making. Unlike classical Bayesian neural networks, which induce predictive uncertainty through a posterior over model parameters, our methods adopt a predictive-first perspective based on martingale posteriors. In particular, we work directly with the one-step-ahead posterior predictive, which we parameterize with a neural network and update sequentially with incoming observations. This decouples Bayesian decision-making from parameter-space inference: we sample from the posterior predictive for decision making, and update the parameters of the posterior predictive via fast, frequentist Kalman-filter-like recursions. Our algorithms operate in a fully online, replay-free setting, providing principled uncertainty quantification without costly posterior sampling. Empirically, they achieve competitive performance-speed trade-offs in non-stationary contextual bandits and Bayesian optimization, offering 10-100 times faster inference than classical Thompson sampling while maintaining comparable or superior decision performance.
title Martingale Posterior Neural Networks for Fast Sequential Decision Making
topic Machine Learning
url https://arxiv.org/abs/2506.11898