Lasry-Lions Envelopes and Nonconvex Optimization: A Homotopy Approach

Fuente: arXiv
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Autori principali: Simões, Miguel, Themelis, Andreas, Patrinos, Panagiotis
Natura: Preprint
Pubblicazione: 2021
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author Simões, Miguel
Themelis, Andreas
Patrinos, Panagiotis
author_facet Simões, Miguel
Themelis, Andreas
Patrinos, Panagiotis
contents In large-scale optimization, the presence of nonsmooth and nonconvex terms in a given problem typically makes it hard to solve. A popular approach to address nonsmooth terms in convex optimization is to approximate them with their respective Moreau envelopes. In this work, we study the use of Lasry-Lions double envelopes to approximate nonsmooth terms that are also not convex. These envelopes are an extension of the Moreau ones but exhibit an additional smoothness property that makes them amenable to fast optimization algorithms. Lasry-Lions envelopes can also be seen as an "intermediate" between a given function and its convex envelope, and we make use of this property to develop a method that builds a sequence of approximate subproblems that are easier to solve than the original problem. We discuss convergence properties of this method when used to address composite minimization problems; additionally, based on a number of experiments, we discuss settings where it may be more useful than classical alternatives in two domains: signal decoding and spectral unmixing.
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id arxiv_https___arxiv_org_abs_2103_08533
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Lasry-Lions Envelopes and Nonconvex Optimization: A Homotopy Approach
Simões, Miguel
Themelis, Andreas
Patrinos, Panagiotis
Optimization and Control
Computer Vision and Pattern Recognition
Signal Processing
Machine Learning
In large-scale optimization, the presence of nonsmooth and nonconvex terms in a given problem typically makes it hard to solve. A popular approach to address nonsmooth terms in convex optimization is to approximate them with their respective Moreau envelopes. In this work, we study the use of Lasry-Lions double envelopes to approximate nonsmooth terms that are also not convex. These envelopes are an extension of the Moreau ones but exhibit an additional smoothness property that makes them amenable to fast optimization algorithms. Lasry-Lions envelopes can also be seen as an "intermediate" between a given function and its convex envelope, and we make use of this property to develop a method that builds a sequence of approximate subproblems that are easier to solve than the original problem. We discuss convergence properties of this method when used to address composite minimization problems; additionally, based on a number of experiments, we discuss settings where it may be more useful than classical alternatives in two domains: signal decoding and spectral unmixing.
title Lasry-Lions Envelopes and Nonconvex Optimization: A Homotopy Approach
topic Optimization and Control
Computer Vision and Pattern Recognition
Signal Processing
Machine Learning
url https://arxiv.org/abs/2103.08533