SemOPT: Fixing Semantic Errors in LLM-based Optimization Modeling via Reward-Guided Search

Zetong Zhou, Wentao Zhang, Jingyuan Wang, Yifan Yang, Zizhuo Wang, Shixi Hu


Abstract
Operations research supports decision-making in domains such as energy, economics, and healthcare. Solving operations research problems typically begins with optimization modeling, which translates a natural-language problem description into executable solver code. LLMs offer a promising way to automate this process, but they remain prone to errors. In practice, these errors can be divided into two categories: syntactic errors refer to solver code that fails to run successfully or is judged infeasible by the solver; semantic errors refer to solver code that successfully returns an objective value but violates the intent of the original problem. Since semantic errors do not trigger runtime failures, they are difficult to detect and rectify. To address this problem, we introduce SemOPT, a semantic-guided framework for correcting LLM-based optimization models. SemOPT combines a semantic reward model that distinguishes faithful math models from plausible but incorrect ones with an adaptive correction system that applies hierarchical reward-guided search over the modeling space. Experiments on seven optimization modeling benchmarks show that SemOPT establishes a new state of the art and achieves an average 7.6% accuracy improvement over the strongest baseline on complex datasets.
Anthology ID:
2026.findings-emnlp.185
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
3937–3953
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URL:
https://aclanthology.org/2026.findings-emnlp.185/
DOI:
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Cite (ACL):
Zetong Zhou, Wentao Zhang, Jingyuan Wang, Yifan Yang, Zizhuo Wang, and Shixi Hu. 2026. SemOPT: Fixing Semantic Errors in LLM-based Optimization Modeling via Reward-Guided Search. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 3937–3953, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SemOPT: Fixing Semantic Errors in LLM-based Optimization Modeling via Reward-Guided Search (Zhou et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.185.pdf