Finite Sample Analysis and Bounds of Generalization Error of Gradient Descent in In-Context Linear Regression

Fuente: arXiv
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Autore principale: Duraisamy, Karthik
Natura: Preprint
Pubblicazione: 2024
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author Duraisamy, Karthik
author_facet Duraisamy, Karthik
contents Recent studies show that transformer-based architectures emulate gradient descent during a forward pass, contributing to in-context learning capabilities - an ability where the model adapts to new tasks based on a sequence of prompt examples without being explicitly trained or fine tuned to do so. This work investigates the generalization properties of a single step of gradient descent in the context of linear regression with well-specified models. A random design setting is considered and analytical expressions are derived for the statistical properties and bounds of generalization error in a non-asymptotic (finite sample) setting. These expressions are notable for avoiding arbitrary constants, and thus offer robust quantitative information and scaling relationships. These results are contrasted with those from classical least squares regression (for which analogous finite sample bounds are also derived), shedding light on systematic and noise components, as well as optimal step sizes. Additionally, identities involving high-order products of Gaussian random matrices are presented as a byproduct of the analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2405_02462
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Finite Sample Analysis and Bounds of Generalization Error of Gradient Descent in In-Context Linear Regression
Duraisamy, Karthik
Statistics Theory
Numerical Analysis
Probability
62J05, 68T10
Recent studies show that transformer-based architectures emulate gradient descent during a forward pass, contributing to in-context learning capabilities - an ability where the model adapts to new tasks based on a sequence of prompt examples without being explicitly trained or fine tuned to do so. This work investigates the generalization properties of a single step of gradient descent in the context of linear regression with well-specified models. A random design setting is considered and analytical expressions are derived for the statistical properties and bounds of generalization error in a non-asymptotic (finite sample) setting. These expressions are notable for avoiding arbitrary constants, and thus offer robust quantitative information and scaling relationships. These results are contrasted with those from classical least squares regression (for which analogous finite sample bounds are also derived), shedding light on systematic and noise components, as well as optimal step sizes. Additionally, identities involving high-order products of Gaussian random matrices are presented as a byproduct of the analysis.
title Finite Sample Analysis and Bounds of Generalization Error of Gradient Descent in In-Context Linear Regression
topic Statistics Theory
Numerical Analysis
Probability
62J05, 68T10
url https://arxiv.org/abs/2405.02462