Architecture-Conditioned Reinforcement Learning Makes Sliding-Window Attention Competitive in Math Reasoning

Kai Liu, Peijie Dong, Xie Xinchen, Jianfei Gao, Qipeng Guo, Xiaowen Chu, Shaoting Zhang, Kai Chen


Abstract
The rapid progress of reasoning and agentic large language models (LLMs) has increased the demand for long-context inference, but self-attention (SA) scales quadratically with context length. To address this, we propose SWARR (Sliding-Window Attention with Reinforced Adaptation for Math Reasoning), a practical recipe for adapting SWA models to mathematical reasoning. SWARR has two stages: (1) efficient conversion from a pretrained SA model to SWA with supervised fine-tuning (SFT), which avoids pretraining a new base model, and (2) architecture-aware policy adaptation with reinforcement learning (RL). We find that SWA still underperforms SA after SFT, and we hypothesize that this gap is caused in part by a data-architecture mismatch: most SFT data are prepared for SA models and may contain long-range dependencies that are difficult for SWA to model. Because RL is architecture-aware and optimizes self-generated trajectories under the SWA constraint, it can adapt training trajectories to better match the SWA architecture. Experiments on mathematical reasoning benchmarks show that this architecture-aware RL substantially narrows the gap between SWA and SA, recovering much of the accuracy lost during SWA conversion while preserving the efficiency benefits of linear-complexity attention.
Anthology ID:
2026.emnlp-main.851
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
19713–19731
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URL:
https://aclanthology.org/2026.emnlp-main.851/
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Cite (ACL):
Kai Liu, Peijie Dong, Xie Xinchen, Jianfei Gao, Qipeng Guo, Xiaowen Chu, Shaoting Zhang, and Kai Chen. 2026. Architecture-Conditioned Reinforcement Learning Makes Sliding-Window Attention Competitive in Math Reasoning. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 19713–19731, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Architecture-Conditioned Reinforcement Learning Makes Sliding-Window Attention Competitive in Math Reasoning (Liu et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.851.pdf