Entropy-Regularized Process Reward Model

Fuente: arXiv
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Main Authors: Zhang, Hanning, Wang, Pengcheng, Diao, Shizhe, Lin, Yong, Pan, Rui, Dong, Hanze, Zhang, Dylan, Molchanov, Pavlo, Zhang, Tong
Format: Preprint
Published: 2024
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author Zhang, Hanning
Wang, Pengcheng
Diao, Shizhe
Lin, Yong
Pan, Rui
Dong, Hanze
Zhang, Dylan
Molchanov, Pavlo
Zhang, Tong
author_facet Zhang, Hanning
Wang, Pengcheng
Diao, Shizhe
Lin, Yong
Pan, Rui
Dong, Hanze
Zhang, Dylan
Molchanov, Pavlo
Zhang, Tong
contents Large language models (LLMs) have shown promise in performing complex multi-step reasoning, yet they continue to struggle with mathematical reasoning, often making systematic errors. A promising solution is reinforcement learning (RL) guided by reward models, particularly those focusing on process rewards, which score each intermediate step rather than solely evaluating the final outcome. This approach is more effective at guiding policy models towards correct reasoning trajectories. In this work, we propose an entropy-regularized process reward model (ER-PRM) that integrates KL-regularized Markov Decision Processes (MDP) to balance policy optimization with the need to prevent the policy from shifting too far from its initial distribution. We derive a novel reward construction method based on the theoretical results. Our theoretical analysis shows that we could derive the optimal reward model from the initial policy sampling. Our empirical experiments on the MATH and GSM8K benchmarks demonstrate that ER-PRM consistently outperforms existing process reward models, achieving 1% improvement on GSM8K and 2-3% improvement on MATH under best-of-N evaluation, and more than 1% improvement under RLHF. These results highlight the efficacy of entropy-regularization in enhancing LLMs' reasoning capabilities.
format Preprint
id arxiv_https___arxiv_org_abs_2412_11006
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Entropy-Regularized Process Reward Model
Zhang, Hanning
Wang, Pengcheng
Diao, Shizhe
Lin, Yong
Pan, Rui
Dong, Hanze
Zhang, Dylan
Molchanov, Pavlo
Zhang, Tong
Machine Learning
Computation and Language
Large language models (LLMs) have shown promise in performing complex multi-step reasoning, yet they continue to struggle with mathematical reasoning, often making systematic errors. A promising solution is reinforcement learning (RL) guided by reward models, particularly those focusing on process rewards, which score each intermediate step rather than solely evaluating the final outcome. This approach is more effective at guiding policy models towards correct reasoning trajectories. In this work, we propose an entropy-regularized process reward model (ER-PRM) that integrates KL-regularized Markov Decision Processes (MDP) to balance policy optimization with the need to prevent the policy from shifting too far from its initial distribution. We derive a novel reward construction method based on the theoretical results. Our theoretical analysis shows that we could derive the optimal reward model from the initial policy sampling. Our empirical experiments on the MATH and GSM8K benchmarks demonstrate that ER-PRM consistently outperforms existing process reward models, achieving 1% improvement on GSM8K and 2-3% improvement on MATH under best-of-N evaluation, and more than 1% improvement under RLHF. These results highlight the efficacy of entropy-regularization in enhancing LLMs' reasoning capabilities.
title Entropy-Regularized Process Reward Model
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2412.11006