RePO: Understanding Preference Learning Through ReLU-Based Optimization

Fuente: arXiv
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Hauptverfasser: Wu, Junkang, Huang, Kexin, Wang, Xue, Gao, Jinyang, Ding, Bolin, Wu, Jiancan, He, Xiangnan, Wang, Xiang
Format: Preprint
Veröffentlicht: 2025
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author Wu, Junkang
Huang, Kexin
Wang, Xue
Gao, Jinyang
Ding, Bolin
Wu, Jiancan
He, Xiangnan
Wang, Xiang
author_facet Wu, Junkang
Huang, Kexin
Wang, Xue
Gao, Jinyang
Ding, Bolin
Wu, Jiancan
He, Xiangnan
Wang, Xiang
contents Aligning large language models (LLMs) with human preferences is critical for real-world deployment, yet existing methods like RLHF face computational and stability challenges. While DPO establishes an offline paradigm with single hyperparameter $β$, subsequent methods like SimPO reintroduce complexity through dual parameters ($β$, $γ$). We propose {ReLU-based Preference Optimization (RePO)}, a streamlined algorithm that eliminates $β$ via two advances: (1) retaining SimPO's reference-free margins but removing $β$ through gradient analysis, and (2) adopting a ReLU-based max-margin loss that naturally filters trivial pairs. Theoretically, RePO is characterized as SimPO's limiting case ($β\to \infty$), where the logistic weighting collapses to binary thresholding, forming a convex envelope of the 0-1 loss. Empirical results on AlpacaEval 2 and Arena-Hard show that RePO outperforms DPO and SimPO across multiple base models, requiring only one hyperparameter to tune.
format Preprint
id arxiv_https___arxiv_org_abs_2503_07426
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle RePO: Understanding Preference Learning Through ReLU-Based Optimization
Wu, Junkang
Huang, Kexin
Wang, Xue
Gao, Jinyang
Ding, Bolin
Wu, Jiancan
He, Xiangnan
Wang, Xiang
Machine Learning
Artificial Intelligence
Aligning large language models (LLMs) with human preferences is critical for real-world deployment, yet existing methods like RLHF face computational and stability challenges. While DPO establishes an offline paradigm with single hyperparameter $β$, subsequent methods like SimPO reintroduce complexity through dual parameters ($β$, $γ$). We propose {ReLU-based Preference Optimization (RePO)}, a streamlined algorithm that eliminates $β$ via two advances: (1) retaining SimPO's reference-free margins but removing $β$ through gradient analysis, and (2) adopting a ReLU-based max-margin loss that naturally filters trivial pairs. Theoretically, RePO is characterized as SimPO's limiting case ($β\to \infty$), where the logistic weighting collapses to binary thresholding, forming a convex envelope of the 0-1 loss. Empirical results on AlpacaEval 2 and Arena-Hard show that RePO outperforms DPO and SimPO across multiple base models, requiring only one hyperparameter to tune.
title RePO: Understanding Preference Learning Through ReLU-Based Optimization
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2503.07426