Tied-Lora: Enhancing parameter efficiency of LoRA with weight tying
Adithya Renduchintala, Tugrul Konuk, Oleksii Kuchaiev
TL;DR
<3-5 sentence high-level summary> Tied-LoRA introduces weight tying across all layers and selective training to drastically reduce trainable parameters in LoRA-like fine-tuning. By sharing low-rank projections A and B and optionally freezing components, TL configurations (notably TL6) achieve performance close to or sometimes surpassing LoRA while using a fraction of the parameters, especially at higher ranks. The approach is evaluated across five diverse tasks using two base LMs (GPT-2B-001 and LLaMA2-7B), showing task-dependent optimal ranks and robust efficiency gains, with translation showing notable parameter reductions (as low as 12.5%). The work suggests that weight tying plus selective training is a promising direction for scalable, cost-effective customization of large language models, with future work extending to larger bases and other PEFT methods including adapters and prefix-tuning.
Abstract
We introduce Tied-LoRA, a novel paradigm leveraging weight tying and selective training to enhance the parameter efficiency of Low-rank Adaptation (LoRA). Our exploration encompasses different plausible combinations of parameter training and freezing, coupled with weight tying, aimed at identifying the optimal trade-off between performance and the count of trainable parameters. Across $5$ diverse tasks and two foundational language models with different parameter counts, our experiments provide comprehensive insights into the inherent trade-offs between efficiency and performance. Our findings reveal a specific Tied-LoRA configuration that distinguishes itself by showcasing comparable performance to LoRA across multiple tasks while utilizing only a fraction of the parameters employed by the standard LoRA method, particularly at elevated ranks. This underscores the efficacy of Tied-LoRA in achieving impressive results with significantly reduced model complexity.
