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Autori principali: Huang, Kun, Pu, Shi, Nedić, Angelia
Natura: Preprint
Pubblicazione: 2024
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Accesso online:https://arxiv.org/abs/2412.13054
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author Huang, Kun
Pu, Shi
Nedić, Angelia
author_facet Huang, Kun
Pu, Shi
Nedić, Angelia
contents Consider $n$ agents connected over a network collaborating to minimize the average of their local cost functions combined with a common nonsmooth function. This paper introduces a unified algorithmic framework for solving such a problem through distributed stochastic proximal gradient methods, leveraging the normal map update scheme. Within this framework, we propose two new algorithms, termed Normal Map-based Distributed Stochastic Gradient Tracking (norM-DSGT) and Normal Map-based Exact Diffusion (norM-ED). We demonstrate that both methods can asymptotically achieve comparable convergence rates to the centralized stochastic proximal gradient descent method under a general variance condition on the stochastic gradients. Additionally, the number of iterations required for norM-ED to achieve such a rate (i.e., the transient time) behaves as $\mathcal{O}(n^{3}/(1-λ)^2)$ for minimizing composite objective functions, matching the performance of the non-proximal ED algorithm. Here $1-λ$ denotes the spectral gap of the mixing matrix related to the underlying network topology. To our knowledge, such a convergence result is state-of-the-art for the considered composite problem. Under the same condition, norM-DSGT enjoys a transient time of $\mathcal{O}(\max\{n^3/(1-λ)^2, n/(1-λ)^3\})$, which matches that of the non-proximal DSGT algorithm and norM-ED under the condition $(1-λ)^{-1}=\mathcal{O}(n^{2})$.
format Preprint
id arxiv_https___arxiv_org_abs_2412_13054
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Distributed Normal Map-based Stochastic Proximal Gradient Methods over Networks
Huang, Kun
Pu, Shi
Nedić, Angelia
Optimization and Control
Consider $n$ agents connected over a network collaborating to minimize the average of their local cost functions combined with a common nonsmooth function. This paper introduces a unified algorithmic framework for solving such a problem through distributed stochastic proximal gradient methods, leveraging the normal map update scheme. Within this framework, we propose two new algorithms, termed Normal Map-based Distributed Stochastic Gradient Tracking (norM-DSGT) and Normal Map-based Exact Diffusion (norM-ED). We demonstrate that both methods can asymptotically achieve comparable convergence rates to the centralized stochastic proximal gradient descent method under a general variance condition on the stochastic gradients. Additionally, the number of iterations required for norM-ED to achieve such a rate (i.e., the transient time) behaves as $\mathcal{O}(n^{3}/(1-λ)^2)$ for minimizing composite objective functions, matching the performance of the non-proximal ED algorithm. Here $1-λ$ denotes the spectral gap of the mixing matrix related to the underlying network topology. To our knowledge, such a convergence result is state-of-the-art for the considered composite problem. Under the same condition, norM-DSGT enjoys a transient time of $\mathcal{O}(\max\{n^3/(1-λ)^2, n/(1-λ)^3\})$, which matches that of the non-proximal DSGT algorithm and norM-ED under the condition $(1-λ)^{-1}=\mathcal{O}(n^{2})$.
title Distributed Normal Map-based Stochastic Proximal Gradient Methods over Networks
topic Optimization and Control
url https://arxiv.org/abs/2412.13054