Sculpting Subspaces: Constrained Full Fine-Tuning in LLMs for Continual Learning

Fuente: arXiv
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Main Authors: Nayak, Nikhil Shivakumar, Killamsetty, Krishnateja, Han, Ligong, Bhandwaldar, Abhishek, Chanda, Prateek, Xu, Kai, Wang, Hao, Pareja, Aldo, Silkin, Oleg, Eyceoz, Mustafa, Srivastava, Akash
Format: Preprint
Published: 2025
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author Nayak, Nikhil Shivakumar
Killamsetty, Krishnateja
Han, Ligong
Bhandwaldar, Abhishek
Chanda, Prateek
Xu, Kai
Wang, Hao
Pareja, Aldo
Silkin, Oleg
Eyceoz, Mustafa
Srivastava, Akash
author_facet Nayak, Nikhil Shivakumar
Killamsetty, Krishnateja
Han, Ligong
Bhandwaldar, Abhishek
Chanda, Prateek
Xu, Kai
Wang, Hao
Pareja, Aldo
Silkin, Oleg
Eyceoz, Mustafa
Srivastava, Akash
contents Continual learning in large language models (LLMs) is prone to catastrophic forgetting, where adapting to new tasks significantly degrades performance on previously learned ones. Existing methods typically rely on low-rank, parameter-efficient updates that limit the model's expressivity and introduce additional parameters per task, leading to scalability issues. To address these limitations, we propose a novel continual full fine-tuning approach leveraging adaptive singular value decomposition (SVD). Our method dynamically identifies task-specific low-rank parameter subspaces and constrains updates to be orthogonal to critical directions associated with prior tasks, thus effectively minimizing interference without additional parameter overhead or storing previous task gradients. We evaluate our approach extensively on standard continual learning benchmarks using both encoder-decoder (T5-Large) and decoder-only (LLaMA-2 7B) models, spanning diverse tasks including classification, generation, and reasoning. Empirically, our method achieves state-of-the-art results, up to 7% higher average accuracy than recent baselines like O-LoRA, and notably maintains the model's general linguistic capabilities, instruction-following accuracy, and safety throughout the continual learning process by reducing forgetting to near-negligible levels. Our adaptive SVD framework effectively balances model plasticity and knowledge retention, providing a practical, theoretically grounded, and computationally scalable solution for continual learning scenarios in large language models.
format Preprint
id arxiv_https___arxiv_org_abs_2504_07097
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sculpting Subspaces: Constrained Full Fine-Tuning in LLMs for Continual Learning
Nayak, Nikhil Shivakumar
Killamsetty, Krishnateja
Han, Ligong
Bhandwaldar, Abhishek
Chanda, Prateek
Xu, Kai
Wang, Hao
Pareja, Aldo
Silkin, Oleg
Eyceoz, Mustafa
Srivastava, Akash
Machine Learning
Artificial Intelligence
Computation and Language
Probability
68T50
I.2.0; G.3
Continual learning in large language models (LLMs) is prone to catastrophic forgetting, where adapting to new tasks significantly degrades performance on previously learned ones. Existing methods typically rely on low-rank, parameter-efficient updates that limit the model's expressivity and introduce additional parameters per task, leading to scalability issues. To address these limitations, we propose a novel continual full fine-tuning approach leveraging adaptive singular value decomposition (SVD). Our method dynamically identifies task-specific low-rank parameter subspaces and constrains updates to be orthogonal to critical directions associated with prior tasks, thus effectively minimizing interference without additional parameter overhead or storing previous task gradients. We evaluate our approach extensively on standard continual learning benchmarks using both encoder-decoder (T5-Large) and decoder-only (LLaMA-2 7B) models, spanning diverse tasks including classification, generation, and reasoning. Empirically, our method achieves state-of-the-art results, up to 7% higher average accuracy than recent baselines like O-LoRA, and notably maintains the model's general linguistic capabilities, instruction-following accuracy, and safety throughout the continual learning process by reducing forgetting to near-negligible levels. Our adaptive SVD framework effectively balances model plasticity and knowledge retention, providing a practical, theoretically grounded, and computationally scalable solution for continual learning scenarios in large language models.
title Sculpting Subspaces: Constrained Full Fine-Tuning in LLMs for Continual Learning
topic Machine Learning
Artificial Intelligence
Computation and Language
Probability
68T50
I.2.0; G.3
url https://arxiv.org/abs/2504.07097