Optimal Rates for Bandit Nonstochastic Control

Y. Jennifer Sun, Stephen Newman, Elad Hazan

Keywords: Bandit control, online learning

Abstract: Linear Quadratic Regulator (LQR) and Linear Quadratic Gaussian (LQG) control are foundational and extensively researched problems in optimal control. We investigate LQR and LQG problems with semi-adversarial perturbations and time-varying adversarial bandit loss functions. The best-known sublinear regret algorithm~\cite{gradu2020non} has a $T^{\frac{3}{4}}$ time horizon dependence, and its authors posed an open question about whether a tight rate of $\sqrt{T}$ could be achieved. We answer in the affirmative, giving an algorithm for bandit LQR and LQG which attains optimal regret, up to logarithmic factors. A central component of our method is a new scheme for bandit convex optimization with memory, which is of independent interest.

Submission Number: 13656