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Main Authors: Pan, Mingjun, Lin, Guanquan, Luo, You-Wei, Zhu, Bin, Dai, Zhien, Sun, Lijun, Yuan, Chun
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2505.08735
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author Pan, Mingjun
Lin, Guanquan
Luo, You-Wei
Zhu, Bin
Dai, Zhien
Sun, Lijun
Yuan, Chun
author_facet Pan, Mingjun
Lin, Guanquan
Luo, You-Wei
Zhu, Bin
Dai, Zhien
Sun, Lijun
Yuan, Chun
contents Reinforcement Learning (RL) has emerged as a powerful tool for neural combinatorial optimization, enabling models to learn heuristics that solve complex problems without requiring expert knowledge. Despite significant progress, existing RL approaches face challenges such as diminishing reward signals and inefficient exploration in vast combinatorial action spaces, leading to inefficiency. In this paper, we propose Preference Optimization, a novel method that transforms quantitative reward signals into qualitative preference signals via statistical comparison modeling, emphasizing the superiority among sampled solutions. Methodologically, by reparameterizing the reward function in terms of policy and utilizing preference models, we formulate an entropy-regularized RL objective that aligns the policy directly with preferences while avoiding intractable computations. Furthermore, we integrate local search techniques into the fine-tuning rather than post-processing to generate high-quality preference pairs, helping the policy escape local optima. Empirical results on various benchmarks, such as the Traveling Salesman Problem (TSP), the Capacitated Vehicle Routing Problem (CVRP) and the Flexible Flow Shop Problem (FFSP), demonstrate that our method significantly outperforms existing RL algorithms, achieving superior convergence efficiency and solution quality.
format Preprint
id arxiv_https___arxiv_org_abs_2505_08735
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Preference Optimization for Combinatorial Optimization Problems
Pan, Mingjun
Lin, Guanquan
Luo, You-Wei
Zhu, Bin
Dai, Zhien
Sun, Lijun
Yuan, Chun
Machine Learning
Reinforcement Learning (RL) has emerged as a powerful tool for neural combinatorial optimization, enabling models to learn heuristics that solve complex problems without requiring expert knowledge. Despite significant progress, existing RL approaches face challenges such as diminishing reward signals and inefficient exploration in vast combinatorial action spaces, leading to inefficiency. In this paper, we propose Preference Optimization, a novel method that transforms quantitative reward signals into qualitative preference signals via statistical comparison modeling, emphasizing the superiority among sampled solutions. Methodologically, by reparameterizing the reward function in terms of policy and utilizing preference models, we formulate an entropy-regularized RL objective that aligns the policy directly with preferences while avoiding intractable computations. Furthermore, we integrate local search techniques into the fine-tuning rather than post-processing to generate high-quality preference pairs, helping the policy escape local optima. Empirical results on various benchmarks, such as the Traveling Salesman Problem (TSP), the Capacitated Vehicle Routing Problem (CVRP) and the Flexible Flow Shop Problem (FFSP), demonstrate that our method significantly outperforms existing RL algorithms, achieving superior convergence efficiency and solution quality.
title Preference Optimization for Combinatorial Optimization Problems
topic Machine Learning
url https://arxiv.org/abs/2505.08735