MLorc: Momentum Low-rank Compression for Memory Efficient Large Language Model Adaptation

Kavli Affiliate: Kyle Shen

| First 5 Authors: Wei Shen, Wei Shen, , ,

| Summary:

With increasing size of large language models (LLMs), full-parameter fine-tuning imposes substantial memory demands. To alleviate this, we propose a novel memory-efficient training paradigm called Momentum Low-rank compression (MLorc). The key idea of MLorc is to compress and reconstruct the momentum of matrix parameters during training to reduce memory consumption. Compared to LoRA, MLorc avoids enforcing a fixed-rank constraint on weight update matrices and thus enables full-parameter learning. Compared to GaLore, MLorc directly compress the momentum rather than gradients, thereby better preserving the training dynamics of full-parameter fine-tuning. We provide a theoretical guarantee for its convergence under mild assumptions. Empirically, MLorc consistently outperforms other memory-efficient training methods, matches or even exceeds the performance of full fine-tuning at small ranks (e.g., $r=4$), and generalizes well across different optimizers — all while not compromising time or memory efficiency.

| Search Query: arXiv Query: search_query=au:Shen&id_list=&start=0&max_results=10

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