SAMoRA: Semantic-Aware Mixture of LoRA Experts for Task-Adaptive Learning
Paper · 2026 · Boyan Shi, Wei Chen, Shuyuan Zhao et al.
Summary
Combining Mixture-of-Experts with LoRA (MoE-LoRA) is a common way to fine-tune LLMs on many tasks at once. The authors identify two weaknesses in this approach. First, MLP routers assign inputs to experts without explicitly considering what each expert is good at, so the experts tend to become alike. Second, a single fixed LoRA scaling factor applies the same update strength to easy and hard tasks.
SAMoRA addresses both problems. It uses an asymmetric design, borrowed from HydraLoRA, with one shared matrix A and several specialized B experts. The shared A doubles as a semantic encoder whose output is compared against learned expert keys to make routing decisions. A Task-Adaptive Scaling module turns task embeddings into sigmoid-bounded diagonal scaling factors. Two auxiliary losses, one for orthogonality and one for semantic matching, push experts toward distinct roles.
On Commonsense Reasoning and GLUE with 8B-scale models, SAMoRA outperforms several LoRA-family baselines while training fewer parameters. This makes it a practical option for efficient multi-task adaptation.
Key points
- Baselines: LoRA, MultiLoRA, MTL-LoRA, MoELoRA, HydraLoRA and MoORE. The authors attribute MoORE's weak results to its small trainable budget, since it trains only the router.
- Ablation on CoLA: Removing task-adaptive scaling causes the largest drop, from 69.75% to 66.43%. Removing the semantic router, L_orth or L_match also lowers scores.
- Expert specialization: PCA plots on Commonsense Reasoning show clearly separated clusters for 8 experts under SAMoRA. The MLP router produces entangled clusters.
- Scaling behavior: On Qwen3-8B, the learned scaling factors for the q/k/v/o projections differ across tasks. Sensitivity tests (N, r, d_g, λ_orth, λ_KL, τ) indicate the method is robust and that small task embeddings are sufficient.
- Limitations and code: The method has not been tested on models of 70B or larger, nor in multimodal settings. Code is available at github.com/boyan-code/SAMoRA.
Institutions
Fields, topics and concepts
📚 Shelves 5The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 worksComputer Vision and Pattern Recognition · 2,869 works
Cite
Cite as Boyan Shi, Wei Chen, Shuyuan Zhao, Junfeng Shen, Shengnan Guo, Shaojiang Wang and Huaiyu Wan. 2026. SAMoRA: Semantic-Aware Mixture of LoRA Experts for Task-Adaptive Learning. Findings of the Association for Computational Linguistics: ACL 2026.
@inproceedings{shi2026samora,
title = {{SAMoRA: Semantic-Aware Mixture of LoRA Experts for Task-Adaptive Learning}},
author = {Boyan Shi, Wei Chen, Shuyuan Zhao, Junfeng Shen, Shengnan Guo, Shaojiang Wang and Huaiyu Wan},
booktitle = {Findings of the Association for Computational Linguistics: ACL 2026},
year = {2026},
doi = {10.18653/v1/2026.findings-acl.1404},
url = {https://doi.org/10.18653/v1/2026.findings-acl.1404}
}References
- Yonatan Bisk, Rowan Zellers, Ronan Le Bras, Jianfeng Gao, and Yejin Choi. 2020. PIQA: reasoning about physical commonsense in natural language. In The Thirty-Fourth AAAI Conference on Artificial Intelligence, AAAI 2020, The Thirty-Second Innovative Applications of Artificial Intelligence Conference,…
- Jiali Chen, Xusen Hei, Yuqi Xue, Zihan Wu, Jiayuan Xie, and Yi Cai. 2025a. Classic4children: Adapting chinese literary classics for children with large language model. In Findings of the Association for Computational Linguistics: NAACL 2025, Albuquerque, New Mexico, USA, April 29 - May 4, 2025, Find… find
- Jiali Chen, Yujie Jia, Zihan Wu, Jinyu Yang, Jianpeng Chen, Xusen Hei, Jiayuan Xie, Yi Cai, and Qing Li. 2025b. Expstar: Towards automatic commentary generation for multi-discipline scientific experiments. In Proceedings of the 33rd ACM International Conference on Multimedia, MM 2025, Dublin, Irelan… find
- Peter Clark, Isaac Cowhey, Oren Etzioni, Tushar Khot, Ashish Sabharwal, Carissa Schoenick, and Oyvind Tafjord. 2018. Think you have solved question answering? try arc, the AI2 reasoning challenge. CoRR, abs/1803.05457.
- William Fedus, Barret Zoph, and Noam Shazeer. 2022. Switch transformers: Scaling to trillion parameter models with simple and efficient sparsity. J. Mach. Learn. Res., 23:120:1–120:39. find
- Wenfeng Feng, Chuzhan Hao, Yuewei Zhang, Yu Han, and Hao Wang. 2024. Mixture-of-loras: An efficient multitask tuning method for large language models. In Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation, LREC/COLING 2024, 20-25 Ma… find
- Wenyi Hong, Wenmeng Yu, Xiaotao Gu, Guo Wang, Guobing Gan, Haomiao Tang, Jiale Cheng, Ji Qi, Junhui Ji, Lihang Pan, Shuaiqi Duan, Weihan Wang, Yan Wang, Yean Cheng, Zehai He, Zhe Su, Zhen Yang, Ziyang Pan, Aohan Zeng, and 58 others. 2025. Glm-4.1v-thinking: Towards versatile multimodal reasoning wit…
- Edward J. Hu, Yelong Shen, Phillip Wallis, Zeyuan Allen-Zhu, Yuanzhi Li, Shean Wang, Lu Wang, and Weizhu Chen. 2022. Lora: Low-rank adaptation of large language models. In The Tenth International Conference on Learning Representations, ICLR 2022, Virtual Event, April 25-29, 2022. OpenReview.net.
- Robert A. Jacobs, Michael I. Jordan, Steven J. Nowlan, and Geoffrey E. Hinton. 1991. Adaptive mixtures of local experts. Neural Comput., 3(1):79–87. find
- Dmitry Lepikhin, HyoukJoong Lee, Yuanzhong Xu, Dehao Chen, Orhan Firat, Yanping Huang, Maxim Krikun, Noam Shazeer, and Zhifeng Chen. 2021. Gshard: Scaling giant models with conditional computation and automatic sharding. In 9th International Conference on Learning Representations, ICLR 2021, Virtual… find
- Mengqi Liao, Wei Chen, Junfeng Shen, Shengnan Guo, and Huaiyu Wan. 2025. Hmora: Making llms more effective with hierarchical mixture of lora experts. In The Thirteenth International Conference on Learning Representations, ICLR 2025, Singapore, April 24-28, 2025. OpenReview.net. find
- Qidong Liu, Xian Wu, Xiangyu Zhao, Yuanshao Zhu, Derong Xu, Feng Tian, and Yefeng Zheng. 2024a. When MOE meets llms: Parameter efficient fine-tuning for multi-task medical applications. In Proceedings of the 47th International ACM SIGIR Conference on Research and Development in Information Retrieval… find
- Shih-Yang Liu, Chien-Yi Wang, Hongxu Yin, Pavlo Molchanov, Yu-Chiang Frank Wang, Kwang-Ting Cheng, and Min-Hung Chen. 2024b. Dora: Weight-decomposed low-rank adaptation. In Forty-first International Conference on Machine Learning, ICML 2024, Vienna, Austria, July 21-27, 2024. OpenReview.net. find
- Chunlin Tian, Zhan Shi, Zhijiang Guo, Li Li, and Cheng-Zhong Xu. 2024. Hydralora: An asymmetric lora architecture for efficient fine-tuning. In Advances in Neural Information Processing Systems 38: Annual Conference on Neural Information Processing Systems 2024, NeurIPS 2024, Vancouver, BC, Canada,… find
- Todor Mihaylov, Peter Clark, Tushar Khot, and Ashish Sabharwal. 2018. Can a suit of armor conduct electricity? A new dataset for open book question answering. CoRR, abs/1809.02789. find
- Alex Wang, Yada Pruksachatkun, Nikita Nangia, Amanpreet Singh, Julian Michael, Felix Hill, Omer Levy, and Samuel R. Bowman. 2019a. Superglue: A stickier benchmark for general-purpose language understanding systems. In Advances in Neural Information Processing Systems 32: Annual Conference on Neural…
- Mohammed Muqeeth, Haokun Liu, and Colin Raffel. 2024. Soft merging of experts with adaptive routing. find
- Trans. Mach. Learn. Res., 2024. find
- Chengwei Qin, Aston Zhang, Zhuosheng Zhang, Jiaao Chen, Michihiro Yasunaga, and Diyi Yang. 2023. Is chatgpt a general-purpose natural language processing task solver? In Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing, EMNLP 2023, Singapore, December 6-10, 2023…
- Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J. Liu. 2020. Exploring the limits of transfer learning with a unified text-to-text transformer. J. Mach. Learn. Res., 21:140:1–140:67.
- Alex Wang, Amanpreet Singh, Julian Michael, Felix Hill, Omer Levy, and Samuel R. Bowman. 2019b. GLUE: A multi-task benchmark and analysis platform for natural language understanding. In 7th International Conference on Learning Representations, ICLR 2019, New Orleans, LA, USA, May 6-9, 2019. OpenRevi…
- Yiming Wang, Yu Lin, Xiaodong Zeng, and Guannan Zhang. 2023. Multilora: Democratizing lora for better multi-task learning. CoRR, abs/2311.11501. — [arXiv:2311.11501](https://arxiv.org/abs/2311.11501) find
- Maarten Sap, Hannah Rashkin, Derek Chen, Ronan Le Bras, and Yejin Choi. 2019. Socialiqa: Commonsense reasoning about social interactions. CoRR, abs/1904.09728.
- Yubo Wang, Xueguang Ma, Ge Zhang, Yuansheng Ni, Abhranil Chandra, Shiguang Guo, Weiming Ren, Aaran Arulraj, Xuan He, Ziyan Jiang, Tianle Li, Max Ku, Kai Wang, Alex Zhuang, Rongqi Fan, Xiang Yue, and Wenhu Chen. 2024. Mmlu-pro: A more robust and challenging multi-task language understanding benchmark…
- Noam Shazeer, Azalia Mirhoseini, Krzysztof Maziarz, Andy Davis, Quoc V. Le, Geoffrey E. Hinton, and Jeff Dean. 2017. Outrageously large neural networks: The sparsely-gated mixture-of-experts layer. In 5th International Conference on Learning Representations, ICLR 2017, Toulon, France, April 24-26, 2… find
- Jason Wei, Maarten Bosma, Vincent Y. Zhao, Kelvin Guu, Adams Wei Yu, Brian Lester, Nan Du, Andrew M. Dai, and Quoc V. Le. 2022. Finetuned language models are zero-shot learners. In The Tenth International Conference on Learning Representations, ICLR 2022, Virtual Event, April 25-29, 2022. OpenReview…
- Alon Talmor, Jonathan Herzig, Nicholas Lourie, and Jonathan Berant. 2019. Commonsenseqa: A question answering challenge targeting commonsense knowledge. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies,…
- Lingling Xu, Haoran Xie, Si-Zhao Joe Qin, Xiaohui Tao, and Fu Lee Wang. 2023. Parameter-efficient fine-tuning methods for pretrained language models: A critical review and assessment. arXiv preprint arXiv:2312.12148. find
- Keisuke Sakaguchi, Ronan Le Bras, Chandra Bhagavatula, and Yejin Choi. 2021. Winogrande: an adversarial winograd schema challenge at scale. Commun. ACM, 64(9):99–106. find
- Llama Team. 2024. The llama 3 herd of models. CoRR, abs/2407.21783.
- Qwen Team. 2025. Qwen3 technical report. CoRR, abs/2505.09388.
- Yaming Yang, Dilxat Muhtar, Yelong Shen, Yuefeng Zhan, Jianfeng Liu, Yujing Wang, Hao Sun, Weiwei Deng, Feng Sun, Qi Zhang, Weizhu Chen, and Yunhai Tong. 2025. Mtl-lora: Low-rank adaptation for multi-task learning. In AAAI-25, Sponsored by the Association for the Advancement of Artificial Intelligen… find
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