Second-order Optimization under Heavy-Tailed Noise: Hessian Clipping and Sample Complexity Limits

Fuente: arXiv
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Auteurs principaux: Sadiev, Abdurakhmon, Richtárik, Peter, Fatkhullin, Ilyas
Format: Preprint
Publié: 2025
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author Sadiev, Abdurakhmon
Richtárik, Peter
Fatkhullin, Ilyas
author_facet Sadiev, Abdurakhmon
Richtárik, Peter
Fatkhullin, Ilyas
contents Heavy-tailed noise is pervasive in modern machine learning applications, arising from data heterogeneity, outliers, and non-stationary stochastic environments. While second-order methods can significantly accelerate convergence in light-tailed or bounded-noise settings, such algorithms are often brittle and lack guarantees under heavy-tailed noise -- precisely the regimes where robustness is most critical. In this work, we take a first step toward a theoretical understanding of second-order optimization under heavy-tailed noise. We consider a setting where stochastic gradients and Hessians have only bounded $p$-th moments, for some $p\in (1,2]$, and establish tight lower bounds on the sample complexity of any second-order method. We then develop a variant of normalized stochastic gradient descent that leverages second-order information and provably matches these lower bounds. To address the instability caused by large deviations, we introduce a novel algorithm based on gradient and Hessian clipping, and prove high-probability upper bounds that nearly match the fundamental limits. Our results provide the first comprehensive sample complexity characterization for second-order optimization under heavy-tailed noise. This positions Hessian clipping as a robust and theoretically sound strategy for second-order algorithm design in heavy-tailed regimes.
format Preprint
id arxiv_https___arxiv_org_abs_2510_10690
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Second-order Optimization under Heavy-Tailed Noise: Hessian Clipping and Sample Complexity Limits
Sadiev, Abdurakhmon
Richtárik, Peter
Fatkhullin, Ilyas
Optimization and Control
Machine Learning
Heavy-tailed noise is pervasive in modern machine learning applications, arising from data heterogeneity, outliers, and non-stationary stochastic environments. While second-order methods can significantly accelerate convergence in light-tailed or bounded-noise settings, such algorithms are often brittle and lack guarantees under heavy-tailed noise -- precisely the regimes where robustness is most critical. In this work, we take a first step toward a theoretical understanding of second-order optimization under heavy-tailed noise. We consider a setting where stochastic gradients and Hessians have only bounded $p$-th moments, for some $p\in (1,2]$, and establish tight lower bounds on the sample complexity of any second-order method. We then develop a variant of normalized stochastic gradient descent that leverages second-order information and provably matches these lower bounds. To address the instability caused by large deviations, we introduce a novel algorithm based on gradient and Hessian clipping, and prove high-probability upper bounds that nearly match the fundamental limits. Our results provide the first comprehensive sample complexity characterization for second-order optimization under heavy-tailed noise. This positions Hessian clipping as a robust and theoretically sound strategy for second-order algorithm design in heavy-tailed regimes.
title Second-order Optimization under Heavy-Tailed Noise: Hessian Clipping and Sample Complexity Limits
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2510.10690