arXiv Statistics ML
5d ago

Improved Regret Bounds for Gaussian Process Upper Confidence Bound in Bayesian Optimization

This paper tackles Bayesian optimization using Gaussian processes, focusing on minimizing regret when the objective function is drawn from a known GP. For a Matérn kernel with sufficient smoothness, the authors prove that the GP-UCB algorithm achieves a cumulative regret of “~O(√T) with high probability. They also establish an “O(√T ln²T)" regret bound for the squared exponential kernel, bridging the gap between previous upper bounds and Scarlett’s 2018 results. The analysis hinges on capturing the concentration of the input sequence generated by GP-UCB to refine the GP’s information‑gain estimates.

By Shogo Iwazaki
arXiv Machine Learning
Oct 8

Towards Regret Guarantees for One-Step Lookahead Bayesian Optimization

The paper investigates theoretical guarantees for a one‑step lookahead Bayesian optimization method called optimal‑point variance reduction (OVR). It derives a uniform Monte Carlo estimation error bound for the acquisition function and shows that a regularized version of OVR achieves a vanishing Bayesian expected simple regret bound. Numerical experiments validate the performance of both OVR and its regularized variant.

By Shion Takeno