Sparse Covariance Matrix Estimation by DCA-Based Algorithms

This letter proposes a novel approach using the [Formula: see text]-norm regularization for the sparse covariance matrix estimation (SCME) problem. The objective function of SCME problem is composed of a nonconvex part and the [Formula: see text] term, which is discontinuous and difficult to tackle....

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Bibliographic Details
Published in:Neural computation Vol. 29; no. 11; p. 3040
Main Authors: Phan, Duy Nhat, Le Thi, Hoai An, Dinh, Tao Pham
Format: Journal Article
Language:English
Published: United States 01.11.2017
ISSN:1530-888X, 1530-888X
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Summary:This letter proposes a novel approach using the [Formula: see text]-norm regularization for the sparse covariance matrix estimation (SCME) problem. The objective function of SCME problem is composed of a nonconvex part and the [Formula: see text] term, which is discontinuous and difficult to tackle. Appropriate DC (difference of convex functions) approximations of [Formula: see text]-norm are used that result in approximation SCME problems that are still nonconvex. DC programming and DCA (DC algorithm), powerful tools in nonconvex programming framework, are investigated. Two DC formulations are proposed and corresponding DCA schemes developed. Two applications of the SCME problem that are considered are classification via sparse quadratic discriminant analysis and portfolio optimization. A careful empirical experiment is performed through simulated and real data sets to study the performance of the proposed algorithms. Numerical results showed their efficiency and their superiority compared with seven state-of-the-art methods.
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ISSN:1530-888X
1530-888X
DOI:10.1162/neco_a_01012