Embedding-perturbed Exploration Preference Optimization for Flow Models

Fuente: arXiv
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Autori principali: Hu, Sujie, Chen, Chubin, Zhu, Jiashu, Wu, Jiahong, Chu, Xiangxiang, Li, Xiu
Natura: Preprint
Pubblicazione: 2026
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author Hu, Sujie
Chen, Chubin
Zhu, Jiashu
Wu, Jiahong
Chu, Xiangxiang
Li, Xiu
author_facet Hu, Sujie
Chen, Chubin
Zhu, Jiashu
Wu, Jiahong
Chu, Xiangxiang
Li, Xiu
contents Recent advancements have established Reinforcement Learning (RL) as a pivotal paradigm for aligning generative models with human intent. However, group-based optimization frameworks (e.g., GRPO) face a critical limitation: the rapid decay of intra-group variance. As the distinctiveness among samples within a group diminishes, the variance approaches zero. This eliminates the very learning signal required for optimization, rendering the process unstable and forcing the policy into premature stagnation or reward hacking. Existing strategies, such as varying the initial noise or increasing group sizes, often fail to address this fundamental issue, resulting in training instability or diminishing returns. To overcome these challenges, we propose $\textbf{Embedding-perturbed Exploration Preference Optimization (}E^2\textbf{PO)}$, a novel framework that sustains optimization through embedding-level perturbation. Our method introduces structured, embedding-level perturbations within sample groups, guaranteeing a robust variance that preserves the discriminative signal throughout the training process. Extensive experiments demonstrate that our approach significantly outperforms state-of-the-art baselines, achieving a more faithful alignment with human preference.
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id arxiv_https___arxiv_org_abs_2605_15803
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publishDate 2026
record_format arxiv
spellingShingle Embedding-perturbed Exploration Preference Optimization for Flow Models
Hu, Sujie
Chen, Chubin
Zhu, Jiashu
Wu, Jiahong
Chu, Xiangxiang
Li, Xiu
Computer Vision and Pattern Recognition
Machine Learning
Recent advancements have established Reinforcement Learning (RL) as a pivotal paradigm for aligning generative models with human intent. However, group-based optimization frameworks (e.g., GRPO) face a critical limitation: the rapid decay of intra-group variance. As the distinctiveness among samples within a group diminishes, the variance approaches zero. This eliminates the very learning signal required for optimization, rendering the process unstable and forcing the policy into premature stagnation or reward hacking. Existing strategies, such as varying the initial noise or increasing group sizes, often fail to address this fundamental issue, resulting in training instability or diminishing returns. To overcome these challenges, we propose $\textbf{Embedding-perturbed Exploration Preference Optimization (}E^2\textbf{PO)}$, a novel framework that sustains optimization through embedding-level perturbation. Our method introduces structured, embedding-level perturbations within sample groups, guaranteeing a robust variance that preserves the discriminative signal throughout the training process. Extensive experiments demonstrate that our approach significantly outperforms state-of-the-art baselines, achieving a more faithful alignment with human preference.
title Embedding-perturbed Exploration Preference Optimization for Flow Models
topic Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2605.15803