A Near-optimal Algorithm for Learning Margin Halfspaces with Massart Noise

Fuente: arXiv
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Auteurs principaux: Diakonikolas, Ilias, Zarifis, Nikos
Format: Preprint
Publié: 2025
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author Diakonikolas, Ilias
Zarifis, Nikos
author_facet Diakonikolas, Ilias
Zarifis, Nikos
contents We study the problem of PAC learning $γ$-margin halfspaces in the presence of Massart noise. Without computational considerations, the sample complexity of this learning problem is known to be $\widetildeΘ(1/(γ^2 ε))$. Prior computationally efficient algorithms for the problem incur sample complexity $\tilde{O}(1/(γ^4 ε^3))$ and achieve 0-1 error of $η+ε$, where $η<1/2$ is the upper bound on the noise rate. Recent work gave evidence of an information-computation tradeoff, suggesting that a quadratic dependence on $1/ε$ is required for computationally efficient algorithms. Our main result is a computationally efficient learner with sample complexity $\widetildeΘ(1/(γ^2 ε^2))$, nearly matching this lower bound. In addition, our algorithm is simple and practical, relying on online SGD on a carefully selected sequence of convex losses.
format Preprint
id arxiv_https___arxiv_org_abs_2501_09691
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Near-optimal Algorithm for Learning Margin Halfspaces with Massart Noise
Diakonikolas, Ilias
Zarifis, Nikos
Machine Learning
Data Structures and Algorithms
Statistics Theory
We study the problem of PAC learning $γ$-margin halfspaces in the presence of Massart noise. Without computational considerations, the sample complexity of this learning problem is known to be $\widetildeΘ(1/(γ^2 ε))$. Prior computationally efficient algorithms for the problem incur sample complexity $\tilde{O}(1/(γ^4 ε^3))$ and achieve 0-1 error of $η+ε$, where $η<1/2$ is the upper bound on the noise rate. Recent work gave evidence of an information-computation tradeoff, suggesting that a quadratic dependence on $1/ε$ is required for computationally efficient algorithms. Our main result is a computationally efficient learner with sample complexity $\widetildeΘ(1/(γ^2 ε^2))$, nearly matching this lower bound. In addition, our algorithm is simple and practical, relying on online SGD on a carefully selected sequence of convex losses.
title A Near-optimal Algorithm for Learning Margin Halfspaces with Massart Noise
topic Machine Learning
Data Structures and Algorithms
Statistics Theory
url https://arxiv.org/abs/2501.09691