Accurate and Efficient Low-Rank Model Merging in Core Space

Fuente: arXiv
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Main Authors: Panariello, Aniello, Marczak, Daniel, Magistri, Simone, Porrello, Angelo, Twardowski, Bartłomiej, Bagdanov, Andrew D., Calderara, Simone, van de Weijer, Joost
Format: Preprint
Published: 2025
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author Panariello, Aniello
Marczak, Daniel
Magistri, Simone
Porrello, Angelo
Twardowski, Bartłomiej
Bagdanov, Andrew D.
Calderara, Simone
van de Weijer, Joost
author_facet Panariello, Aniello
Marczak, Daniel
Magistri, Simone
Porrello, Angelo
Twardowski, Bartłomiej
Bagdanov, Andrew D.
Calderara, Simone
van de Weijer, Joost
contents In this paper, we address the challenges associated with merging low-rank adaptations of large neural networks. With the rise of parameter-efficient adaptation techniques, such as Low-Rank Adaptation (LoRA), model fine-tuning has become more accessible. While fine-tuning models with LoRA is highly efficient, existing merging methods often sacrifice this efficiency by merging fully-sized weight matrices. We propose the Core Space merging framework, which enables the merging of LoRA-adapted models within a common alignment basis, thereby preserving the efficiency of low-rank adaptation while substantially improving accuracy across tasks. We further provide a formal proof that projection into Core Space ensures no loss of information and provide a complexity analysis showing the efficiency gains. Extensive empirical results demonstrate that Core Space significantly improves existing merging techniques and achieves state-of-the-art results on both vision and language tasks while utilizing a fraction of the computational resources. Codebase is available at https://github.com/apanariello4/core-space-merging.
format Preprint
id arxiv_https___arxiv_org_abs_2509_17786
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Accurate and Efficient Low-Rank Model Merging in Core Space
Panariello, Aniello
Marczak, Daniel
Magistri, Simone
Porrello, Angelo
Twardowski, Bartłomiej
Bagdanov, Andrew D.
Calderara, Simone
van de Weijer, Joost
Computer Vision and Pattern Recognition
Artificial Intelligence
In this paper, we address the challenges associated with merging low-rank adaptations of large neural networks. With the rise of parameter-efficient adaptation techniques, such as Low-Rank Adaptation (LoRA), model fine-tuning has become more accessible. While fine-tuning models with LoRA is highly efficient, existing merging methods often sacrifice this efficiency by merging fully-sized weight matrices. We propose the Core Space merging framework, which enables the merging of LoRA-adapted models within a common alignment basis, thereby preserving the efficiency of low-rank adaptation while substantially improving accuracy across tasks. We further provide a formal proof that projection into Core Space ensures no loss of information and provide a complexity analysis showing the efficiency gains. Extensive empirical results demonstrate that Core Space significantly improves existing merging techniques and achieves state-of-the-art results on both vision and language tasks while utilizing a fraction of the computational resources. Codebase is available at https://github.com/apanariello4/core-space-merging.
title Accurate and Efficient Low-Rank Model Merging in Core Space
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2509.17786