Stacked LoRA: Isolated Low-Rank Adaptation for Lifelong Knowledge Management

Heramb Vivek Patil, Vaishnavee Sanam, Minakshi Pradeep Atre


Abstract
Continual learning (CL) presents a significant challenge for large pre-trained models, primarily due to catastrophic forgetting and the high computational cost of sequential knowledge updating. Parameter-Efficient Transfer Learning (PETL) methods offer reduced computational burdens but often struggle to effectively mitigate forgetting. This paper introduces Stacked Low-Rank Adaptation (SLoRA), a novel parameter-efficient approach that leverages the additive composition of task-specific, frozen low-rank adapters to enable modular continual learning with inherent support for explicit knowledge modification. SLoRA was evaluated on vision benchmarks, BERT-base, and the 1-billion-parameter Llama-3.2-1B model. Experiments demonstrated that SLoRA almost completely eliminated catastrophic forgetting, achieving a final average accuracy of 92.75% on Llama-3.2-1B while perfectly preserving prior task performance. Furthermore, SLoRA is computationally efficient, enabling up to a 15x training speed-up over full fine-tuning with 99.7% fewer trainable parameters per update. SLoRA offers a compelling balance of forgetting mitigation, parameter efficiency, and modularity, representing a promising direction for developing adaptable and efficient lifelong knowledgeable foundation models.
Anthology ID:
2025.ijcnlp-srw.4
Volume:
The 14th International Joint Conference on Natural Language Processing and The 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics
Month:
December
Year:
2025
Address:
Mumbai, India
Editors:
Santosh T.y.s.s, Shuichiro Shimizu, Yifan Gong
Venue:
IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
36–46
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URL:
https://preview.aclanthology.org/ingest-ijcnlp-aacl/2025.ijcnlp-srw.4/
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Cite (ACL):
Heramb Vivek Patil, Vaishnavee Sanam, and Minakshi Pradeep Atre. 2025. Stacked LoRA: Isolated Low-Rank Adaptation for Lifelong Knowledge Management. In The 14th International Joint Conference on Natural Language Processing and The 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics, pages 36–46, Mumbai, India. Association for Computational Linguistics.
Cite (Informal):
Stacked LoRA: Isolated Low-Rank Adaptation for Lifelong Knowledge Management (Patil et al., IJCNLP 2025)
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https://preview.aclanthology.org/ingest-ijcnlp-aacl/2025.ijcnlp-srw.4.pdf