The Annals of Statistics
- Ann. Statist.
- Volume 42, Number 6 (2014), 2164-2201.
Optimal computational and statistical rates of convergence for sparse nonconvex learning problems
Zhaoran Wang, Han Liu, and Tong Zhang
Abstract
We provide theoretical analysis of the statistical and computational properties of penalized $M$-estimators that can be formulated as the solution to a possibly nonconvex optimization problem. Many important estimators fall in this category, including least squares regression with nonconvex regularization, generalized linear models with nonconvex regularization and sparse elliptical random design regression. For these problems, it is intractable to calculate the global solution due to the nonconvex formulation. In this paper, we propose an approximate regularization path-following method for solving a variety of learning problems with nonconvex objective functions. Under a unified analytic framework, we simultaneously provide explicit statistical and computational rates of convergence for any local solution attained by the algorithm. Computationally, our algorithm attains a global geometric rate of convergence for calculating the full regularization path, which is optimal among all first-order algorithms. Unlike most existing methods that only attain geometric rates of convergence for one single regularization parameter, our algorithm calculates the full regularization path with the same iteration complexity. In particular, we provide a refined iteration complexity bound to sharply characterize the performance of each stage along the regularization path. Statistically, we provide sharp sample complexity analysis for all the approximate local solutions along the regularization path. In particular, our analysis improves upon existing results by providing a more refined sample complexity bound as well as an exact support recovery result for the final estimator. These results show that the final estimator attains an oracle statistical property due to the usage of nonconvex penalty.
Article information
Source
Ann. Statist. Volume 42, Number 6 (2014), 2164-2201.
Dates
First available in Project Euclid: 20 October 2014
Permanent link to this document
http://projecteuclid.org/euclid.aos/1413810725
Digital Object Identifier
doi:10.1214/14-AOS1238
Mathematical Reviews number (MathSciNet)
MR3269977
Zentralblatt MATH identifier
1302.62066
Subjects
Primary: 62F30: Inference under constraints 90C26: Nonconvex programming, global optimization
Secondary: 62J12: Generalized linear models 90C52: Methods of reduced gradient type
Keywords
Nonconvex regularized $M$-estimation path-following method geometric computational rate optimal statistical rate
Citation
Wang, Zhaoran; Liu, Han; Zhang, Tong. Optimal computational and statistical rates of convergence for sparse nonconvex learning problems. Ann. Statist. 42 (2014), no. 6, 2164--2201. doi:10.1214/14-AOS1238. http://projecteuclid.org/euclid.aos/1413810725.
Supplemental materials
- Supplementary material: Optimal computational and statistical rates of convergence for sparse nonconvex learning problems. We provide the detailed proof in the supplement [Wang, Liu and Zhang (2014)].Digital Object Identifier: doi:10.1214/14-AOS1238SUPPSupplemental files available for subscribers.

