Title
Linear Convergence of First- and Zeroth-Order Primal–Dual Algorithms for Distributed Nonconvex Optimization
Abstract
This article considers the distributed nonconvex optimization problem of minimizing a global cost function formed by a sum of local cost functions by using local information exchange. We first consider a distributed first-order primal–dual algorithm. We show that it converges sublinearly to a stationary point if each local cost function is smooth and linearly to a global optimum under an additional condition that the global cost function satisfies the Polyak–Łojasiewicz condition. This condition is weaker than strong convexity, which is a standard condition for proving linear convergence of distributed optimization algorithms, and the global minimizer is not necessarily unique. Motivated by the situations where the gradients are unavailable, we then propose a distributed zeroth-order algorithm, derived from the considered first-order algorithm by using a deterministic gradient estimator, and show that it has the same convergence properties as the considered first-order algorithm under the same conditions. The theoretical results are illustrated by numerical simulations.
Year
DOI
Venue
2022
10.1109/TAC.2021.3108501
IEEE Transactions on Automatic Control
Keywords
DocType
Volume
Distributed nonconvex optimization,first-order algorithm,linear convergence,primal–dual algorithm,zeroth-order algorithm
Journal
67
Issue
ISSN
Citations 
8
0018-9286
1
PageRank 
References 
Authors
0.36
33
5
Name
Order
Citations
PageRank
Xinlei Yi11169.37
Shengjun Zhang210.36
Tao Yang316076.32
Tianyou Chai4135.59
Karl Henrik Johansson53996322.75