Stabilizing Temporal Difference Learning via Implicit Stochastic Recursion
Temporal difference (TD) learning is a foundational algorithm in reinforcement learning (RL). For nearly forty years, TD learning has served as a workhorse for applied RL as well as a building block for more complex and specialized algorithms. However, despite its widespread use, TD procedures are generally sensitive to step size specification. A poor choice of step size can dramatically increase variance and slow convergence in both on-policy and off-policy evaluation tasks. In practice, researchers use trial and error to identify stable step sizes, but these approaches tend to be ad hoc and inefficient. As an alternative, we propose implicit TD algorithms that reformulate TD updates into fixed point equations. Such updates are more stable and less sensitive to step size without sacrificing computational efficiency. Moreover, we derive asymptotic convergence guarantees and finite-time error bounds for our proposed implicit TD algorithms, which include implicit TD(0), TD($\lambda$), and TD with gradient correction (TDC). Our results show that implicit TD algorithms are applicable to a much broader range of step sizes, and thus provide a robust and versatile framework for policy evaluation and value approximation in modern RL tasks. We demonstrate these benefits empirically through extensive numerical examples spanning both on-policy and off-policy tasks.
Code (0)
등록된 구현이 없습니다.
Tasks
Computational EfficiencyOff-policy evaluationReinforcement Learning (RL)Methods 이 논문이 사용한 방법론
Similar Papers 제목 키워드 기반
Two Timescale Stochastic Approximation with Controlled Markov noise and Off-policy temporal difference learning
We present for the first time an asymptotic convergence analysis of two time-scale stochastic approximation driven by `controlled' Markov noise. In particular, both the faster and slower recursions have non-additive cont…
A Finite-Iteration Theory for Asynchronous Categorical Distributional Temporal-Difference Learning
We study finite-iteration behavior of the exact asynchronous recursions used by categorical distributional temporal-difference methods. The analysis covers scalar categorical TD in the Cramér geometry and multivariate si…
$N$-Timescale Stochastic Approximation: Stability and Convergence
This paper presents the first sufficient conditions that guarantee the stability and almost sure convergence of $N$-timescale stochastic approximation (SA) iterates for any $N\geq1$. It extends the existing results on On…
n-Step Temporal Difference Learning with Optimal n
We consider the problem of finding the optimal value of n in the n-step temporal difference (TD) learning algorithm. Our objective function for the optimization problem is the average root mean squared error (RMSE). We f…
Stochastic OptimizationStochastic Approximation with Markov Noise: Analysis and applications in reinforcement learning
We present for the first time an asymptotic convergence analysis of two time-scale stochastic approximation driven by "controlled" Markov noise. In particular, the faster and slower recursions have non-additive controlle…
reinforcement-learningReinforcement Learning (RL)