TRONTOR: To RoPE or Not to RoPE for Long-Context Modeling

Youngjun Son, Jongyeon Park, Jaejin Lee


Abstract
While Rotary Position Embedding (RoPE) is widely used in large language models, its inductive biases can impair long-context reasoning and lead to attention sinks. In this work, we propose TRONTOR, a method that effectively combines RoPE and No Positional Encoding (NoPE) through a simple fine-tuning phase, bypassing the need for expensive pretraining modifications. Our preliminary experiments demonstrate that mixing RoPE and NoPE at the attention-head level can enhance long-context capabilities, while static selection strategies fail to capture the varying complexity of inputs. Based on this observation, TRONTOR employs a lightweight context-aware routing method that dynamically switches each attention head between RoPE and NoPE at every token step. This router-only configuration provides an efficient operating point, yielding long-context performance gains with minimal inference overhead. For further gains, we extend TRONTOR to TRONTOR-Agg, which applies simple unweighted averaging over multiple RoPE bases within RoPE-active heads while avoiding learnable intra-head routing. Evaluated on the RULER benchmark using Llama-3.2 (1B and 3B) and Qwen3 (1.7B and 4B), TRONTOR improves long-context performance by mitigating attention sinks and dynamically reallocating attention toward relevant mid-context tokens.
Anthology ID:
2026.findings-emnlp.836
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
Note:
Pages:
17720–17733
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.836/
DOI:
Bibkey:
Cite (ACL):
Youngjun Son, Jongyeon Park, and Jaejin Lee. 2026. TRONTOR: To RoPE or Not to RoPE for Long-Context Modeling. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 17720–17733, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
TRONTOR: To RoPE or Not to RoPE for Long-Context Modeling (Son et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.836.pdf