Abstract
In this paper we study general \(l_p\) regularized unconstrained minimization problems. In particular, we derive lower bounds for nonzero entries of the first- and second-order stationary points and hence also of local minimizers of the \(l_p\) minimization problems. We extend some existing iterative reweighted \(l_1\) (\(\mathrm{IRL}_1\)) and \(l_2\) (\(\mathrm{IRL}_2\)) minimization methods to solve these problems and propose new variants for them in which each subproblem has a closed-form solution. Also, we provide a unified convergence analysis for these methods. In addition, we propose a novel Lipschitz continuous \({\epsilon }\)-approximation to \(\Vert x\Vert ^p_p\). Using this result, we develop new \(\mathrm{IRL}_1\) methods for the \(l_p\) minimization problems and show that any accumulation point of the sequence generated by these methods is a first-order stationary point, provided that the approximation parameter \({\epsilon }\) is below a computable threshold value. This is a remarkable result since all existing iterative reweighted minimization methods require that \({\epsilon }\) be dynamically updated and approach zero. Our computational results demonstrate that the new \(\mathrm{IRL}_1\) method and the new variants generally outperform the existing \(\mathrm{IRL}_1\) methods (Chen and Zhou in 2012; Foucart and Lai in Appl Comput Harmon Anal 26:395–407, 2009).
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This work was supported in part by NSERC Discovery Grant. Part of this work was conducted during the author’s sabbatical leave in the Department of Industrial and Systems Engineering at Texas A&M University. The author would like to thank them for hosting his visit.
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Lu, Z. Iterative reweighted minimization methods for \(l_p\) regularized unconstrained nonlinear programming. Math. Program. 147, 277–307 (2014). https://doi.org/10.1007/s10107-013-0722-4
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DOI: https://doi.org/10.1007/s10107-013-0722-4