AdvantageFlow: Advantage-Weighted Least Squares for RL in Flow Models

Fuente: arXiv
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Autores principales: Kveton, Branislav, Rao, Anup, Mukherjee, Subhojyoti, Singh, Krishna Kumar, Lai, Viet Dac
Formato: Preprint
Publicado: 2026
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author Kveton, Branislav
Rao, Anup
Mukherjee, Subhojyoti
Singh, Krishna Kumar
Lai, Viet Dac
author_facet Kveton, Branislav
Rao, Anup
Mukherjee, Subhojyoti
Singh, Krishna Kumar
Lai, Viet Dac
contents We introduce AdvantageFlow, a forward-process reinforcement learning algorithm for rectified flow models. Unlike Flow-GRPO, which optimizes the reverse process, we optimize an advantage-weighted forward-process prediction loss. This optimization problem is unstable when advantages are negative and the loss becomes non-convex. We stabilize it by rollout policy regularization, which reduces variance and arises from fitting a local reward-improving target distribution. We evaluate AdvantageFlow on image generation tasks with Stable Diffusion 3.5 Medium. It outperforms both Flow-GRPO and a state-of-the-art forward-process RL baseline based on negative-aware fine-tuning.
format Preprint
id arxiv_https___arxiv_org_abs_2605_26013
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle AdvantageFlow: Advantage-Weighted Least Squares for RL in Flow Models
Kveton, Branislav
Rao, Anup
Mukherjee, Subhojyoti
Singh, Krishna Kumar
Lai, Viet Dac
Machine Learning
Artificial Intelligence
Computer Vision and Pattern Recognition
We introduce AdvantageFlow, a forward-process reinforcement learning algorithm for rectified flow models. Unlike Flow-GRPO, which optimizes the reverse process, we optimize an advantage-weighted forward-process prediction loss. This optimization problem is unstable when advantages are negative and the loss becomes non-convex. We stabilize it by rollout policy regularization, which reduces variance and arises from fitting a local reward-improving target distribution. We evaluate AdvantageFlow on image generation tasks with Stable Diffusion 3.5 Medium. It outperforms both Flow-GRPO and a state-of-the-art forward-process RL baseline based on negative-aware fine-tuning.
title AdvantageFlow: Advantage-Weighted Least Squares for RL in Flow Models
topic Machine Learning
Artificial Intelligence
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.26013