Policy Gradient Guidance Enables Test Time Control

Fuente: arXiv
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Main Authors: Qi, Jianing, Tang, Hao, Zhu, Zhigang
Format: Preprint
Published: 2025
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author Qi, Jianing
Tang, Hao
Zhu, Zhigang
author_facet Qi, Jianing
Tang, Hao
Zhu, Zhigang
contents We introduce Policy Gradient Guidance (PGG), a simple extension of classifier-free guidance from diffusion models to classical policy gradient methods. PGG augments the policy gradient with an unconditional branch and interpolates conditional and unconditional branches, yielding a test-time control knob that modulates behavior without retraining. We provide a theoretical derivation showing that the additional normalization term vanishes under advantage estimation, leading to a clean guided policy gradient update. Empirically, we evaluate PGG on discrete and continuous control benchmarks. We find that conditioning dropout-central to diffusion guidance-offers gains in simple discrete tasks and low sample regimes, but dropout destabilizes continuous control. Training with modestly larger guidance ($γ>1$) consistently improves stability, sample efficiency, and controllability. Our results show that guidance, previously confined to diffusion policies, can be adapted to standard on-policy methods, opening new directions for controllable online reinforcement learning.
format Preprint
id arxiv_https___arxiv_org_abs_2510_02148
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Policy Gradient Guidance Enables Test Time Control
Qi, Jianing
Tang, Hao
Zhu, Zhigang
Machine Learning
We introduce Policy Gradient Guidance (PGG), a simple extension of classifier-free guidance from diffusion models to classical policy gradient methods. PGG augments the policy gradient with an unconditional branch and interpolates conditional and unconditional branches, yielding a test-time control knob that modulates behavior without retraining. We provide a theoretical derivation showing that the additional normalization term vanishes under advantage estimation, leading to a clean guided policy gradient update. Empirically, we evaluate PGG on discrete and continuous control benchmarks. We find that conditioning dropout-central to diffusion guidance-offers gains in simple discrete tasks and low sample regimes, but dropout destabilizes continuous control. Training with modestly larger guidance ($γ>1$) consistently improves stability, sample efficiency, and controllability. Our results show that guidance, previously confined to diffusion policies, can be adapted to standard on-policy methods, opening new directions for controllable online reinforcement learning.
title Policy Gradient Guidance Enables Test Time Control
topic Machine Learning
url https://arxiv.org/abs/2510.02148