Optimal Complexity in Byzantine-Robust Distributed Stochastic Optimization with Data Heterogeneity

Fuente: arXiv
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Main Authors: Shi, Qiankun, Peng, Jie, Yuan, Kun, Wang, Xiao, Ling, Qing
Format: Preprint
Published: 2025
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author Shi, Qiankun
Peng, Jie
Yuan, Kun
Wang, Xiao
Ling, Qing
author_facet Shi, Qiankun
Peng, Jie
Yuan, Kun
Wang, Xiao
Ling, Qing
contents In this paper, we establish tight lower bounds for Byzantine-robust distributed first-order stochastic optimization methods in both strongly convex and non-convex stochastic optimization. We reveal that when the distributed nodes have heterogeneous data, the convergence error comprises two components: a non-vanishing Byzantine error and a vanishing optimization error. We establish the lower bounds on the Byzantine error and on the minimum number of queries to a stochastic gradient oracle required to achieve an arbitrarily small optimization error. Nevertheless, we identify significant discrepancies between our established lower bounds and the existing upper bounds. To fill this gap, we leverage the techniques of Nesterov's acceleration and variance reduction to develop novel Byzantine-robust distributed stochastic optimization methods that provably match these lower bounds, up to logarithmic factors, implying that our established lower bounds are tight.
format Preprint
id arxiv_https___arxiv_org_abs_2503_16337
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimal Complexity in Byzantine-Robust Distributed Stochastic Optimization with Data Heterogeneity
Shi, Qiankun
Peng, Jie
Yuan, Kun
Wang, Xiao
Ling, Qing
Optimization and Control
Machine Learning
In this paper, we establish tight lower bounds for Byzantine-robust distributed first-order stochastic optimization methods in both strongly convex and non-convex stochastic optimization. We reveal that when the distributed nodes have heterogeneous data, the convergence error comprises two components: a non-vanishing Byzantine error and a vanishing optimization error. We establish the lower bounds on the Byzantine error and on the minimum number of queries to a stochastic gradient oracle required to achieve an arbitrarily small optimization error. Nevertheless, we identify significant discrepancies between our established lower bounds and the existing upper bounds. To fill this gap, we leverage the techniques of Nesterov's acceleration and variance reduction to develop novel Byzantine-robust distributed stochastic optimization methods that provably match these lower bounds, up to logarithmic factors, implying that our established lower bounds are tight.
title Optimal Complexity in Byzantine-Robust Distributed Stochastic Optimization with Data Heterogeneity
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2503.16337