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arXiv 2402.08562cs.CLcs.AI
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较高层需要更多LoRA专家

Higher Layers Need More LoRA Experts

Northwestern University(西北大学);Mineral Research(矿物研究机构);Google DeepMind(谷歌DeepMind)

Chongyang Gao, Kezhen Chen, Jinmeng Rao, Baochen Sun, Ruibo Liu, Daiyi Peng, Yawen Zhang, Xiaoyuan Guo, Jie Yang, VS Subrahmanian

AI总结:

本文提出了一种新颖的参数高效MoE方法MoLA,通过为Transformer模型的不同层灵活分配不同数量的LoRA专家,发现在专家总数固定时向更高层分配更多专家可显著提升性能并减少参数,在多个基准上取得了优异表现。

摘要:

参数高效微调(PEFT)技术,如低秩适应(LoRA),在大型语言模型上提供了训练效率,但其对模型性能的影响仍然有限。近期的努力将LoRA与混合专家(Mixture-of-Experts, MoE)相结合,以提升PEFT方法的性能。尽管取得了有前景的结果,但关于利用MoE提升LoRA效率的研究仍处于早期阶段。近期研究表明,MoE架构中的专家具有不同的优势,并且也表现出一些冗余。这一结论是否也适用于参数高效的MoE?在本文中,我们提出了一种新颖的参数高效MoE方法,即带有分层专家分配的MoE-LoRA(MoLA),适用于基于Transformer的模型,其中每个模型层可以灵活地使用不同数量的LoRA专家。我们研究了几种具有不同分层专家配置的架构。在六个知名的NLP和常识问答基准上的实验表明,MoLA与所有基线相比取得了同等或更优的性能。我们发现,在专家总数固定的情况下,将更多的LoRA专家分配给较高层可以进一步提升模型的有效性。在参数数量大幅减少的情况下,这种分配策略优于在每一层分配相同数量专家的设置。这项工作可以作为一种即插即用的参数高效微调方法,广泛应用于各种应用中。代码可在https://github.com/GCYZSL/MoLA获取。

英文摘要:

Parameter-efficient tuning (PEFT) techniques like low-rank adaptation (LoRA) offer training efficiency on Large Language Models, but their impact on model performance remains limited. Recent efforts integrate LoRA and Mixture-of-Experts (MoE) to improve the performance of PEFT methods. Despite promising results, research on improving the efficiency of LoRA with MoE is still in its early stages. Recent studies have shown that experts in the MoE architecture have different strengths and also exhibit some redundancy. Does this statement also apply to parameter-efficient MoE? In this paper, we introduce a novel parameter-efficient MoE method, \textit{\textbf{M}oE-L\textbf{o}RA with \textbf{L}ayer-wise Expert \textbf{A}llocation (MoLA)} for Transformer-based models, where each model layer has the flexibility to employ a varying number of LoRA experts. We investigate several architectures with varying layer-wise expert configurations. Experiments on six well-known NLP and commonsense QA benchmarks demonstrate that MoLA achieves equal or superior performance compared to all baselines. We find that allocating more LoRA experts to higher layers further enhances the effectiveness of models with a certain number of experts in total. With much fewer parameters, this allocation strategy outperforms the setting with the same number of experts in every layer. This work can be widely used as a plug-and-play parameter-efficient tuning approach for various applications. The code is available at https://github.com/GCYZSL/MoLA.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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