CoMoL: Efficient Mixture of LoRA Experts via Dynamic Core Space Merging

Fuente: arXiv
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Main Authors: Cao, Jie, Fan, Zhenxuan, Wang, Zhuonan, Lin, Tianwei, Zhao, Ziyuan, Yan, Rolan, Zhang, Wenqiao, Shao, Feifei, Wang, Hongwei, Xiao, Jun, Tang, Siliang
Format: Preprint
Published: 2026
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author Cao, Jie
Fan, Zhenxuan
Wang, Zhuonan
Lin, Tianwei
Zhao, Ziyuan
Yan, Rolan
Zhang, Wenqiao
Shao, Feifei
Wang, Hongwei
Xiao, Jun
Tang, Siliang
author_facet Cao, Jie
Fan, Zhenxuan
Wang, Zhuonan
Lin, Tianwei
Zhao, Ziyuan
Yan, Rolan
Zhang, Wenqiao
Shao, Feifei
Wang, Hongwei
Xiao, Jun
Tang, Siliang
contents Large language models (LLMs) achieve remarkable performance on diverse downstream and domain-specific tasks via parameter-efficient fine-tuning (PEFT). However, existing PEFT methods, particularly MoE-LoRA architectures, suffer from limited parameter efficiency and coarse-grained adaptation due to the proliferation of LoRA experts and instance-level routing. To address these issues, we propose Core Space Mixture of LoRA (\textbf{CoMoL}), a novel MoE-LoRA framework that incorporates expert diversity, parameter efficiency, and fine-grained adaptation. Specifically, CoMoL introduces two key components: core space experts and core space routing. Core space experts store each expert in a compact core matrix, preserving diversity while controlling parameter growth. Core space routing dynamically selects and activates the appropriate core experts for each token, enabling fine-grained, input-adaptive routing. Activated core experts are then merged via a soft-merging strategy into a single core expert, which is combined with a shared LoRA to form a specialized LoRA module. Besides, the routing network is projected into the same low-rank space as the LoRA matrices, further reducing parameter overhead without compromising expressiveness. Extensive experiments demonstrate that CoMoL retains the adaptability of MoE-LoRA architectures while achieving parameter efficiency comparable to standard LoRA, consistently outperforming existing methods across multiple tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2603_00573
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CoMoL: Efficient Mixture of LoRA Experts via Dynamic Core Space Merging
Cao, Jie
Fan, Zhenxuan
Wang, Zhuonan
Lin, Tianwei
Zhao, Ziyuan
Yan, Rolan
Zhang, Wenqiao
Shao, Feifei
Wang, Hongwei
Xiao, Jun
Tang, Siliang
Computation and Language
Large language models (LLMs) achieve remarkable performance on diverse downstream and domain-specific tasks via parameter-efficient fine-tuning (PEFT). However, existing PEFT methods, particularly MoE-LoRA architectures, suffer from limited parameter efficiency and coarse-grained adaptation due to the proliferation of LoRA experts and instance-level routing. To address these issues, we propose Core Space Mixture of LoRA (\textbf{CoMoL}), a novel MoE-LoRA framework that incorporates expert diversity, parameter efficiency, and fine-grained adaptation. Specifically, CoMoL introduces two key components: core space experts and core space routing. Core space experts store each expert in a compact core matrix, preserving diversity while controlling parameter growth. Core space routing dynamically selects and activates the appropriate core experts for each token, enabling fine-grained, input-adaptive routing. Activated core experts are then merged via a soft-merging strategy into a single core expert, which is combined with a shared LoRA to form a specialized LoRA module. Besides, the routing network is projected into the same low-rank space as the LoRA matrices, further reducing parameter overhead without compromising expressiveness. Extensive experiments demonstrate that CoMoL retains the adaptability of MoE-LoRA architectures while achieving parameter efficiency comparable to standard LoRA, consistently outperforming existing methods across multiple tasks.
title CoMoL: Efficient Mixture of LoRA Experts via Dynamic Core Space Merging
topic Computation and Language
url https://arxiv.org/abs/2603.00573