SAMG: Offline-to-Online Reinforcement Learning via State-Action-Conditional Offline Model Guidance
Liyu Zhang, Haochi Wu, Xu Wan, Quan Kong, Ruilong Deng, Mingyang Sun
TL;DR
SAMG tackles inefficiency in offline-to-online RL by freezing a pre-trained offline critic and guiding online refinement through a state-action-conditional coefficient that weighs offline guidance. The method integrates a frozen Q^{off} with the online Q via a data-driven coefficient p(s,a) learned from a conditional VAE, enabling 100% online data usage and avoiding reliance on offline data during online learning. The authors provide contraction-based theoretical analysis showing convergence to the online optimal policy and faster convergence on in-distribution samples, plus empirical wins on D4RL benchmarks. Limitations arise when offline coverage is narrow, suggesting adaptive data-sharing or OOD strategies as future work.
Abstract
Offline-to-online (O2O) reinforcement learning (RL) pre-trains models on offline data and refines policies through online fine-tuning. However, existing O2O RL algorithms typically require maintaining the tedious offline datasets to mitigate the effects of out-of-distribution (OOD) data, which significantly limits their efficiency in exploiting online samples. To address this deficiency, we introduce a new paradigm for O2O RL called State-Action-Conditional Offline \Model Guidance (SAMG). It freezes the pre-trained offline critic to provide compact offline understanding for each state-action sample, thus eliminating the need for retraining on offline data. The frozen offline critic is incorporated with the online target critic weighted by a state-action-adaptive coefficient. This coefficient aims to capture the offline degree of samples at the state-action level, and is updated adaptively during training. In practice, SAMG could be easily integrated with Q-function-based algorithms. Theoretical analysis shows good optimality and lower estimation error. Empirically, SAMG outperforms state-of-the-art O2O RL algorithms on the D4RL benchmark.
