Title
Structured Nonconvex and Nonsmooth Optimization: Algorithms and Iteration Complexity Analysis.
Abstract
Nonconvex and nonsmooth optimization problems are frequently encountered in much of statistics, business, science and engineering, but they are not yet widely recognized as a technology in the sense of scalability. A reason for this relatively low degree of popularity is the lack of a well developed system of theory and algorithms to support the applications, as is the case for its convex counterpart. This paper aims to take one step in the direction of disciplined nonconvex and nonsmooth optimization. In particular, we consider in this paper some constrained nonconvex optimization models in block decision variables, with or without coupled affine constraints. In the absence of coupled constraints, we show a sublinear rate of convergence to an \(\epsilon \)-stationary solution in the form of variational inequality for a generalized conditional gradient method, where the convergence rate is dependent on the Hölderian continuity of the gradient of the smooth part of the objective. For the model with coupled affine constraints, we introduce corresponding \(\epsilon \)-stationarity conditions, and apply two proximal-type variants of the ADMM to solve such a model, assuming the proximal ADMM updates can be implemented for all the block variables except for the last block, for which either a gradient step or a majorization–minimization step is implemented. We show an iteration complexity bound of \(O(1/\epsilon ^2)\) to reach an \(\epsilon \)-stationary solution for both algorithms. Moreover, we show that the same iteration complexity of a proximal BCD method follows immediately. Numerical results are provided to illustrate the efficacy of the proposed algorithms for tensor robust PCA and tensor sparse PCA problems.
Year
DOI
Venue
2019
10.1007/s10589-018-0034-y
Computational Optimization and Applications
Keywords
DocType
Volume
Structured nonconvex optimization, $$\epsilon $$ϵ-Stationary, Iteration complexity, Conditional gradient method, Alternating direction method of multipliers, Block coordinate descent method, 90C26, 90C06, 90C60
Journal
abs/1605.02408
Issue
ISSN
Citations 
1
0926-6003
12
PageRank 
References 
Authors
0.52
31
4
Name
Order
Citations
PageRank
Bo Jiang1625.55
Tianyi Lin214711.79
Shiqian Ma3106863.48
Shuzhong Zhang42808181.66