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Main Authors: Malinovsky, Grigory, Michieli, Umberto, Hammoud, Hasan Abed Al Kader, Ceritli, Taha, Elesedy, Hayder, Ozay, Mete, Richtárik, Peter
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2410.08305
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author Malinovsky, Grigory
Michieli, Umberto
Hammoud, Hasan Abed Al Kader
Ceritli, Taha
Elesedy, Hayder
Ozay, Mete
Richtárik, Peter
author_facet Malinovsky, Grigory
Michieli, Umberto
Hammoud, Hasan Abed Al Kader
Ceritli, Taha
Elesedy, Hayder
Ozay, Mete
Richtárik, Peter
contents Fine-tuning has become a popular approach to adapting large foundational models to specific tasks. As the size of models and datasets grows, parameter-efficient fine-tuning techniques are increasingly important. One of the most widely used methods is Low-Rank Adaptation (LoRA), with adaptation update expressed as the product of two low-rank matrices. While LoRA was shown to possess strong performance in fine-tuning, it often under-performs when compared to full-parameter fine-tuning (FPFT). Although many variants of LoRA have been extensively studied empirically, their theoretical optimization analysis is heavily under-explored. The starting point of our work is a demonstration that LoRA and its two extensions, Asymmetric LoRA and Chain of LoRA, indeed encounter convergence issues. To address these issues, we propose Randomized Asymmetric Chain of LoRA (RAC-LoRA) -- a general optimization framework that rigorously analyzes the convergence rates of LoRA-based methods. Our approach inherits the empirical benefits of LoRA-style heuristics, but introduces several small but important algorithmic modifications which turn it into a provably convergent method. Our framework serves as a bridge between FPFT and low-rank adaptation. We provide provable guarantees of convergence to the same solution as FPFT, along with the rate of convergence. Additionally, we present a convergence analysis for smooth, non-convex loss functions, covering gradient descent, stochastic gradient descent, and federated learning settings. Our theoretical findings are supported by experimental results.
format Preprint
id arxiv_https___arxiv_org_abs_2410_08305
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Randomized Asymmetric Chain of LoRA: The First Meaningful Theoretical Framework for Low-Rank Adaptation
Malinovsky, Grigory
Michieli, Umberto
Hammoud, Hasan Abed Al Kader
Ceritli, Taha
Elesedy, Hayder
Ozay, Mete
Richtárik, Peter
Machine Learning
Optimization and Control
Fine-tuning has become a popular approach to adapting large foundational models to specific tasks. As the size of models and datasets grows, parameter-efficient fine-tuning techniques are increasingly important. One of the most widely used methods is Low-Rank Adaptation (LoRA), with adaptation update expressed as the product of two low-rank matrices. While LoRA was shown to possess strong performance in fine-tuning, it often under-performs when compared to full-parameter fine-tuning (FPFT). Although many variants of LoRA have been extensively studied empirically, their theoretical optimization analysis is heavily under-explored. The starting point of our work is a demonstration that LoRA and its two extensions, Asymmetric LoRA and Chain of LoRA, indeed encounter convergence issues. To address these issues, we propose Randomized Asymmetric Chain of LoRA (RAC-LoRA) -- a general optimization framework that rigorously analyzes the convergence rates of LoRA-based methods. Our approach inherits the empirical benefits of LoRA-style heuristics, but introduces several small but important algorithmic modifications which turn it into a provably convergent method. Our framework serves as a bridge between FPFT and low-rank adaptation. We provide provable guarantees of convergence to the same solution as FPFT, along with the rate of convergence. Additionally, we present a convergence analysis for smooth, non-convex loss functions, covering gradient descent, stochastic gradient descent, and federated learning settings. Our theoretical findings are supported by experimental results.
title Randomized Asymmetric Chain of LoRA: The First Meaningful Theoretical Framework for Low-Rank Adaptation
topic Machine Learning
Optimization and Control
url https://arxiv.org/abs/2410.08305