On-the-fly Preference Alignment via Principle-Guided Decoding

Fuente: arXiv
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Auteurs principaux: Zhu, Mingye, Liu, Yi, Zhang, Lei, Guo, Junbo, Mao, Zhendong
Format: Preprint
Publié: 2025
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author Zhu, Mingye
Liu, Yi
Zhang, Lei
Guo, Junbo
Mao, Zhendong
author_facet Zhu, Mingye
Liu, Yi
Zhang, Lei
Guo, Junbo
Mao, Zhendong
contents With the rapidly expanding landscape of large language models, aligning model generations with human values and preferences is becoming increasingly important. Popular alignment methods, such as Reinforcement Learning from Human Feedback, have shown significant success in guiding models with greater control. However, these methods require considerable computational resources, which is inefficient, and substantial collection of training data to accommodate the diverse and pluralistic nature of human preferences, which is impractical. These limitations significantly constrain the scope and efficacy of both task-specific and general preference alignment methods. In this work, we introduce On-the-fly Preference Alignment via Principle-Guided Decoding (OPAD) to directly align model outputs with human preferences during inference, eliminating the need for fine-tuning. Our approach involves first curating a surrogate solution to an otherwise infeasible optimization problem and then designing a principle-guided reward function based on this surrogate. The final aligned policy is derived by maximizing this customized reward, which exploits the discrepancy between the constrained policy and its unconstrained counterpart. OPAD directly modifies the model's predictions during inference, ensuring principle adherence without incurring the computational overhead of retraining or fine-tuning. Experiments show that OPAD achieves competitive or superior performance in both general and personalized alignment tasks, demonstrating its efficiency and effectiveness compared to state-of-the-art baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2502_14204
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On-the-fly Preference Alignment via Principle-Guided Decoding
Zhu, Mingye
Liu, Yi
Zhang, Lei
Guo, Junbo
Mao, Zhendong
Computation and Language
Artificial Intelligence
With the rapidly expanding landscape of large language models, aligning model generations with human values and preferences is becoming increasingly important. Popular alignment methods, such as Reinforcement Learning from Human Feedback, have shown significant success in guiding models with greater control. However, these methods require considerable computational resources, which is inefficient, and substantial collection of training data to accommodate the diverse and pluralistic nature of human preferences, which is impractical. These limitations significantly constrain the scope and efficacy of both task-specific and general preference alignment methods. In this work, we introduce On-the-fly Preference Alignment via Principle-Guided Decoding (OPAD) to directly align model outputs with human preferences during inference, eliminating the need for fine-tuning. Our approach involves first curating a surrogate solution to an otherwise infeasible optimization problem and then designing a principle-guided reward function based on this surrogate. The final aligned policy is derived by maximizing this customized reward, which exploits the discrepancy between the constrained policy and its unconstrained counterpart. OPAD directly modifies the model's predictions during inference, ensuring principle adherence without incurring the computational overhead of retraining or fine-tuning. Experiments show that OPAD achieves competitive or superior performance in both general and personalized alignment tasks, demonstrating its efficiency and effectiveness compared to state-of-the-art baselines.
title On-the-fly Preference Alignment via Principle-Guided Decoding
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2502.14204