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Main Authors: de Lara, Nathan Samuel, Shkurti, Florian
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.17632
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author de Lara, Nathan Samuel
Shkurti, Florian
author_facet de Lara, Nathan Samuel
Shkurti, Florian
contents Modern offline Reinforcement Learning (RL) methods find performant actor-critics, however, fine-tuning these actor-critics online with value-based RL algorithms typically causes immediate drops in performance. We provide evidence consistent with the hypothesis that, in the loss landscape, offline maxima for prior algorithms and online maxima are separated by low-performance valleys that gradient-based fine-tuning traverses. Following this, we present Score Matched Actor-Critic (SMAC), an offline RL method designed to learn actor-critics that transition to online value-based RL algorithms with no drop in performance. SMAC avoids valleys between offline and online maxima by regularizing the Q-function during the offline phase to respect a first-order derivative equality between the score of the policy and action-gradient of the Q-function. We experimentally demonstrate that SMAC converges to offline maxima that are connected to better online maxima via paths with monotonically increasing reward found by first-order optimization. SMAC achieves smooth transfer to Soft Actor-Critic and TD3 in 6/6 D4RL tasks. In 4/6 environments, it reduces regret by 34-58% over the best baseline.
format Preprint
id arxiv_https___arxiv_org_abs_2602_17632
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle SMAC: Score-Matched Actor-Critics for Robust Offline-to-Online Transfer
de Lara, Nathan Samuel
Shkurti, Florian
Machine Learning
Artificial Intelligence
Modern offline Reinforcement Learning (RL) methods find performant actor-critics, however, fine-tuning these actor-critics online with value-based RL algorithms typically causes immediate drops in performance. We provide evidence consistent with the hypothesis that, in the loss landscape, offline maxima for prior algorithms and online maxima are separated by low-performance valleys that gradient-based fine-tuning traverses. Following this, we present Score Matched Actor-Critic (SMAC), an offline RL method designed to learn actor-critics that transition to online value-based RL algorithms with no drop in performance. SMAC avoids valleys between offline and online maxima by regularizing the Q-function during the offline phase to respect a first-order derivative equality between the score of the policy and action-gradient of the Q-function. We experimentally demonstrate that SMAC converges to offline maxima that are connected to better online maxima via paths with monotonically increasing reward found by first-order optimization. SMAC achieves smooth transfer to Soft Actor-Critic and TD3 in 6/6 D4RL tasks. In 4/6 environments, it reduces regret by 34-58% over the best baseline.
title SMAC: Score-Matched Actor-Critics for Robust Offline-to-Online Transfer
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.17632