Accelerated Gradient Methods for Sparse Statistical Learning with Nonconvex Penalties

Fuente: arXiv
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Autores principales: Yang, Kai, Asgharian, Masoud, Bhatnagar, Sahir
Formato: Preprint
Publicado: 2020
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author Yang, Kai
Asgharian, Masoud
Bhatnagar, Sahir
author_facet Yang, Kai
Asgharian, Masoud
Bhatnagar, Sahir
contents Nesterov's accelerated gradient (AG) is a popular technique to optimize objective functions comprising two components: a convex loss and a penalty function. While AG methods perform well for convex penalties, such as the LASSO, convergence issues may arise when it is applied to nonconvex penalties, such as SCAD. A recent proposal generalizes Nesterov's AG method to the nonconvex setting. The proposed algorithm requires specification of several hyperparameters for its practical application. Aside from some general conditions, there is no explicit rule for selecting the hyperparameters, and how different selection can affect convergence of the algorithm. In this article, we propose a hyperparameter setting based on the complexity upper bound to accelerate convergence, and consider the application of this nonconvex AG algorithm to high-dimensional linear and logistic sparse learning problems. We further establish the rate of convergence and present a simple and useful bound to characterize our proposed optimal damping sequence. Simulation studies show that convergence can be made, on average, considerably faster than that of the conventional proximal gradient algorithm. Our experiments also show that the proposed method generally outperforms the current state-of-the-art methods in terms of signal recovery.
format Preprint
id arxiv_https___arxiv_org_abs_2009_10629
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Accelerated Gradient Methods for Sparse Statistical Learning with Nonconvex Penalties
Yang, Kai
Asgharian, Masoud
Bhatnagar, Sahir
Optimization and Control
Computation
Machine Learning
Nesterov's accelerated gradient (AG) is a popular technique to optimize objective functions comprising two components: a convex loss and a penalty function. While AG methods perform well for convex penalties, such as the LASSO, convergence issues may arise when it is applied to nonconvex penalties, such as SCAD. A recent proposal generalizes Nesterov's AG method to the nonconvex setting. The proposed algorithm requires specification of several hyperparameters for its practical application. Aside from some general conditions, there is no explicit rule for selecting the hyperparameters, and how different selection can affect convergence of the algorithm. In this article, we propose a hyperparameter setting based on the complexity upper bound to accelerate convergence, and consider the application of this nonconvex AG algorithm to high-dimensional linear and logistic sparse learning problems. We further establish the rate of convergence and present a simple and useful bound to characterize our proposed optimal damping sequence. Simulation studies show that convergence can be made, on average, considerably faster than that of the conventional proximal gradient algorithm. Our experiments also show that the proposed method generally outperforms the current state-of-the-art methods in terms of signal recovery.
title Accelerated Gradient Methods for Sparse Statistical Learning with Nonconvex Penalties
topic Optimization and Control
Computation
Machine Learning
url https://arxiv.org/abs/2009.10629