QuAILoRA: Quantization-Aware Initialization for LoRA

Fuente: arXiv
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Autori principali: Lawton, Neal, Padmakumar, Aishwarya, Gaspers, Judith, FitzGerald, Jack, Kumar, Anoop, Steeg, Greg Ver, Galstyan, Aram
Natura: Preprint
Pubblicazione: 2024
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author Lawton, Neal
Padmakumar, Aishwarya
Gaspers, Judith
FitzGerald, Jack
Kumar, Anoop
Steeg, Greg Ver
Galstyan, Aram
author_facet Lawton, Neal
Padmakumar, Aishwarya
Gaspers, Judith
FitzGerald, Jack
Kumar, Anoop
Steeg, Greg Ver
Galstyan, Aram
contents QLoRA reduces the memory-cost of fine-tuning a large language model (LLM) with LoRA by quantizing the base LLM. However, quantization introduces quantization errors that negatively impact model performance after fine-tuning. In this paper we introduce QuAILoRA, a quantization-aware initialization for LoRA that mitigates this negative impact by decreasing quantization errors at initialization. Our method spends a small amount of computational overhead to compute this quantization-aware initialization, without increasing the memory-cost of fine-tuning. We evaluate our method on several causal language modeling and downstream evaluation tasks using several different model sizes and families. We observe that almost all LLMs fined-tuned with QuAILoRA achieve better validation perplexity. When evaluated on downstream tasks, we find that QuAILoRA yields improvements proportional to the negative effect of quantization error. On average, applying QuAILoRA to 4-bit QLoRA models yields 75% of the validation perplexity decrease and 86% of the downstream task accuracy increase as doubling the quantization precision to 8-bit, without increasing GPU memory utilization during fine-tuning.
format Preprint
id arxiv_https___arxiv_org_abs_2410_14713
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle QuAILoRA: Quantization-Aware Initialization for LoRA
Lawton, Neal
Padmakumar, Aishwarya
Gaspers, Judith
FitzGerald, Jack
Kumar, Anoop
Steeg, Greg Ver
Galstyan, Aram
Machine Learning
Computation and Language
68T50
QLoRA reduces the memory-cost of fine-tuning a large language model (LLM) with LoRA by quantizing the base LLM. However, quantization introduces quantization errors that negatively impact model performance after fine-tuning. In this paper we introduce QuAILoRA, a quantization-aware initialization for LoRA that mitigates this negative impact by decreasing quantization errors at initialization. Our method spends a small amount of computational overhead to compute this quantization-aware initialization, without increasing the memory-cost of fine-tuning. We evaluate our method on several causal language modeling and downstream evaluation tasks using several different model sizes and families. We observe that almost all LLMs fined-tuned with QuAILoRA achieve better validation perplexity. When evaluated on downstream tasks, we find that QuAILoRA yields improvements proportional to the negative effect of quantization error. On average, applying QuAILoRA to 4-bit QLoRA models yields 75% of the validation perplexity decrease and 86% of the downstream task accuracy increase as doubling the quantization precision to 8-bit, without increasing GPU memory utilization during fine-tuning.
title QuAILoRA: Quantization-Aware Initialization for LoRA
topic Machine Learning
Computation and Language
68T50
url https://arxiv.org/abs/2410.14713