Self-concordant smoothing in proximal quasi-Newton algorithms for large-scale convex composite optimization

Fuente: arXiv
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Main Authors: Adeoye, Adeyemi D., Bemporad, Alberto
Format: Preprint
Published: 2023
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author Adeoye, Adeyemi D.
Bemporad, Alberto
author_facet Adeoye, Adeyemi D.
Bemporad, Alberto
contents We introduce a notion of self-concordant smoothing for minimizing the sum of two convex functions, one of which is smooth and the other nonsmooth. The key highlight is a natural property of the resulting problem's structure that yields a variable metric selection method and a step length rule especially suited to proximal quasi-Newton algorithms. Also, we efficiently handle specific structures promoted by the nonsmooth term, such as l1-regularization and group lasso penalties. A convergence analysis for the class of proximal quasi-Newton methods covered by our framework is presented. In particular, we obtain guarantees, under standard assumptions, for two algorithms: Prox-N-SCORE (a proximal Newton method) and Prox-GGN-SCORE (a proximal generalized Gauss-Newton method). The latter uses a low-rank approximation of the Hessian inverse, reducing most of the cost of matrix inversion and making it effective for overparameterized machine learning models. Numerical experiments on synthetic and real data demonstrate the efficiency of both algorithms against state-of-the-art approaches. A Julia implementation is publicly available at https://github.com/adeyemiadeoye/SelfConcordantSmoothOptimization.jl.
format Preprint
id arxiv_https___arxiv_org_abs_2309_01781
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Self-concordant smoothing in proximal quasi-Newton algorithms for large-scale convex composite optimization
Adeoye, Adeyemi D.
Bemporad, Alberto
Optimization and Control
Machine Learning
65K05 90C06 49M15
We introduce a notion of self-concordant smoothing for minimizing the sum of two convex functions, one of which is smooth and the other nonsmooth. The key highlight is a natural property of the resulting problem's structure that yields a variable metric selection method and a step length rule especially suited to proximal quasi-Newton algorithms. Also, we efficiently handle specific structures promoted by the nonsmooth term, such as l1-regularization and group lasso penalties. A convergence analysis for the class of proximal quasi-Newton methods covered by our framework is presented. In particular, we obtain guarantees, under standard assumptions, for two algorithms: Prox-N-SCORE (a proximal Newton method) and Prox-GGN-SCORE (a proximal generalized Gauss-Newton method). The latter uses a low-rank approximation of the Hessian inverse, reducing most of the cost of matrix inversion and making it effective for overparameterized machine learning models. Numerical experiments on synthetic and real data demonstrate the efficiency of both algorithms against state-of-the-art approaches. A Julia implementation is publicly available at https://github.com/adeyemiadeoye/SelfConcordantSmoothOptimization.jl.
title Self-concordant smoothing in proximal quasi-Newton algorithms for large-scale convex composite optimization
topic Optimization and Control
Machine Learning
65K05 90C06 49M15
url https://arxiv.org/abs/2309.01781