A Stochastic Operator Framework for Optimization and Learning with Sub-Weibull Errors

Fuente: arXiv
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Main Authors: Bastianello, Nicola, Madden, Liam, Carli, Ruggero, Dall'Anese, Emiliano
Format: Preprint
Published: 2021
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author Bastianello, Nicola
Madden, Liam
Carli, Ruggero
Dall'Anese, Emiliano
author_facet Bastianello, Nicola
Madden, Liam
Carli, Ruggero
Dall'Anese, Emiliano
contents This paper proposes a framework to study the convergence of stochastic optimization and learning algorithms. The framework is modeled over the different challenges that these algorithms pose, such as (i) the presence of random additive errors (e.g. due to stochastic gradients), and (ii) random coordinate updates (e.g. due to asynchrony in distributed set-ups). The paper covers both convex and strongly convex problems, and it also analyzes online scenarios, involving changes in the data and costs. The paper relies on interpreting stochastic algorithms as the iterated application of stochastic operators, thus allowing us to use the powerful tools of operator theory. In particular, we consider operators characterized by additive errors with sub-Weibull distribution (which parameterize a broad class of errors by their tail probability), and random updates. In this framework we derive convergence results in mean and in high probability, by providing bounds to the distance of the current iteration from a solution of the optimization or learning problem. The contributions are discussed in light of federated learning applications.
format Preprint
id arxiv_https___arxiv_org_abs_2105_09884
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle A Stochastic Operator Framework for Optimization and Learning with Sub-Weibull Errors
Bastianello, Nicola
Madden, Liam
Carli, Ruggero
Dall'Anese, Emiliano
Optimization and Control
Systems and Control
This paper proposes a framework to study the convergence of stochastic optimization and learning algorithms. The framework is modeled over the different challenges that these algorithms pose, such as (i) the presence of random additive errors (e.g. due to stochastic gradients), and (ii) random coordinate updates (e.g. due to asynchrony in distributed set-ups). The paper covers both convex and strongly convex problems, and it also analyzes online scenarios, involving changes in the data and costs. The paper relies on interpreting stochastic algorithms as the iterated application of stochastic operators, thus allowing us to use the powerful tools of operator theory. In particular, we consider operators characterized by additive errors with sub-Weibull distribution (which parameterize a broad class of errors by their tail probability), and random updates. In this framework we derive convergence results in mean and in high probability, by providing bounds to the distance of the current iteration from a solution of the optimization or learning problem. The contributions are discussed in light of federated learning applications.
title A Stochastic Operator Framework for Optimization and Learning with Sub-Weibull Errors
topic Optimization and Control
Systems and Control
url https://arxiv.org/abs/2105.09884