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Main Authors: Xu, Xiaoang, Wang, Shuo, Han, Xu, Liu, Zhenghao, Wu, Huijia, Li, Peipei, Liu, Zhiyuan, Sun, Maosong, He, Zhaofeng
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2505.24550
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author Xu, Xiaoang
Wang, Shuo
Han, Xu
Liu, Zhenghao
Wu, Huijia
Li, Peipei
Liu, Zhiyuan
Sun, Maosong
He, Zhaofeng
author_facet Xu, Xiaoang
Wang, Shuo
Han, Xu
Liu, Zhenghao
Wu, Huijia
Li, Peipei
Liu, Zhiyuan
Sun, Maosong
He, Zhaofeng
contents Large Reasoning Models (LRMs) achieve superior performance by extending the thought length. However, a lengthy thinking trajectory leads to reduced efficiency. Most of the existing methods are stuck in the assumption of overthinking and attempt to reason efficiently by compressing the Chain-of-Thought, but this often leads to performance degradation. To address this problem, we introduce A*-Thought, an efficient tree search-based unified framework designed to identify and isolate the most essential thoughts from the extensive reasoning chains produced by these models. It formulates the reasoning process of LRMs as a search tree, where each node represents a reasoning span in the giant reasoning space. By combining the A* search algorithm with a cost function specific to the reasoning path, it can efficiently compress the chain of thought and determine a reasoning path with high information density and low cost. In addition, we also propose a bidirectional importance estimation mechanism, which further refines this search process and enhances its efficiency beyond uniform sampling. Extensive experiments on several advanced math tasks show that A*-Thought effectively balances performance and efficiency over a huge search space. Specifically, A*-Thought can improve the performance of QwQ-32B by 2.39$\times$ with low-budget and reduce the length of the output token by nearly 50% with high-budget. The proposed method is also compatible with several other LRMs, demonstrating its generalization capability. The code can be accessed at: https://github.com/AI9Stars/AStar-Thought.
format Preprint
id arxiv_https___arxiv_org_abs_2505_24550
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A*-Thought: Efficient Reasoning via Bidirectional Compression for Low-Resource Settings
Xu, Xiaoang
Wang, Shuo
Han, Xu
Liu, Zhenghao
Wu, Huijia
Li, Peipei
Liu, Zhiyuan
Sun, Maosong
He, Zhaofeng
Computation and Language
Large Reasoning Models (LRMs) achieve superior performance by extending the thought length. However, a lengthy thinking trajectory leads to reduced efficiency. Most of the existing methods are stuck in the assumption of overthinking and attempt to reason efficiently by compressing the Chain-of-Thought, but this often leads to performance degradation. To address this problem, we introduce A*-Thought, an efficient tree search-based unified framework designed to identify and isolate the most essential thoughts from the extensive reasoning chains produced by these models. It formulates the reasoning process of LRMs as a search tree, where each node represents a reasoning span in the giant reasoning space. By combining the A* search algorithm with a cost function specific to the reasoning path, it can efficiently compress the chain of thought and determine a reasoning path with high information density and low cost. In addition, we also propose a bidirectional importance estimation mechanism, which further refines this search process and enhances its efficiency beyond uniform sampling. Extensive experiments on several advanced math tasks show that A*-Thought effectively balances performance and efficiency over a huge search space. Specifically, A*-Thought can improve the performance of QwQ-32B by 2.39$\times$ with low-budget and reduce the length of the output token by nearly 50% with high-budget. The proposed method is also compatible with several other LRMs, demonstrating its generalization capability. The code can be accessed at: https://github.com/AI9Stars/AStar-Thought.
title A*-Thought: Efficient Reasoning via Bidirectional Compression for Low-Resource Settings
topic Computation and Language
url https://arxiv.org/abs/2505.24550