Evolutionary Guided Decoding: Iterative Value Refinement for LLMs

Fuente: arXiv
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Main Authors: Liu, Zhenhua, Li, Lijun, Chen, Ruizhe, Jiang, Yuxian, Zhu, Tong, Su, Zhaochen, Chen, Wenliang, Shao, Jing
Format: Preprint
Published: 2025
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_version_ 1866912628068057088
author Liu, Zhenhua
Li, Lijun
Chen, Ruizhe
Jiang, Yuxian
Zhu, Tong
Su, Zhaochen
Chen, Wenliang
Shao, Jing
author_facet Liu, Zhenhua
Li, Lijun
Chen, Ruizhe
Jiang, Yuxian
Zhu, Tong
Su, Zhaochen
Chen, Wenliang
Shao, Jing
contents While guided decoding, especially value-guided methods, has emerged as a cost-effective alternative for controlling language model outputs without re-training models, its effectiveness is limited by the accuracy of the value function. We identify that this inaccuracy stems from a core distributional gap: existing methods train static value functions on trajectories sampled exclusively from the base policy, which inherently confines their training to a narrow and suboptimal view of the potential output space. We propose Iterative Value Refinement, a novel framework designed to bridge this gap. It employs Value Exploration to provide a more comprehensive and robust training signal, complemented by Iterative Self-Refinement, which uses the improved value function from one iteration to guide the generation of higher-quality data for the next. Extensive experiments on text summarization, multi-turn dialogue, and instruction following demonstrate the effectiveness of our framework in aligning language models. Our approach not only achieves alignment but also significantly reduces computational costs by leveraging principled value function optimization for efficient and effective control.
format Preprint
id arxiv_https___arxiv_org_abs_2503_02368
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Evolutionary Guided Decoding: Iterative Value Refinement for LLMs
Liu, Zhenhua
Li, Lijun
Chen, Ruizhe
Jiang, Yuxian
Zhu, Tong
Su, Zhaochen
Chen, Wenliang
Shao, Jing
Computation and Language
Artificial Intelligence
Machine Learning
While guided decoding, especially value-guided methods, has emerged as a cost-effective alternative for controlling language model outputs without re-training models, its effectiveness is limited by the accuracy of the value function. We identify that this inaccuracy stems from a core distributional gap: existing methods train static value functions on trajectories sampled exclusively from the base policy, which inherently confines their training to a narrow and suboptimal view of the potential output space. We propose Iterative Value Refinement, a novel framework designed to bridge this gap. It employs Value Exploration to provide a more comprehensive and robust training signal, complemented by Iterative Self-Refinement, which uses the improved value function from one iteration to guide the generation of higher-quality data for the next. Extensive experiments on text summarization, multi-turn dialogue, and instruction following demonstrate the effectiveness of our framework in aligning language models. Our approach not only achieves alignment but also significantly reduces computational costs by leveraging principled value function optimization for efficient and effective control.
title Evolutionary Guided Decoding: Iterative Value Refinement for LLMs
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2503.02368