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Autori principali: Karmarkar, Tanmaya, Lucet, Yves
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2505.06442
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author Karmarkar, Tanmaya
Lucet, Yves
author_facet Karmarkar, Tanmaya
Lucet, Yves
contents We propose the first linear-time algorithm to compute the conjugate of (nonconvex) bivariate piecewise linear-quadratic (PLQ) functions (bivariate quadratic functions defined on a polyhedral subdivision). Our algorithm starts with computing the convex envelope of each quadratic piece obtaining rational functions (quadratic over linear) defined over a polyhedral subdivision. Then we compute the conjugate of each resulting piece to obtain piecewise quadratic functions defined over a parabolic subdivision. Finally we compute the maximum of all those functions to obtain the conjugate as a piecewise quadratic function defined on a parabolic subdivision. The resulting algorithm runs in linear time if the initial subdivision is a triangulation (or has a uniform upper bound on the number of vertexes for each piece). Our open-source implementation in MATLAB uses symbolic computation and rational numbers to avoid floating-point errors, and merges pieces as soon as possible to minimize computation time.
format Preprint
id arxiv_https___arxiv_org_abs_2505_06442
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A linear-time algorithm to compute the conjugate of nonconvex bivariate piecewise linear-quadratic functions
Karmarkar, Tanmaya
Lucet, Yves
Optimization and Control
Symbolic Computation
90C25, 65K10, 49M29, 26B25
We propose the first linear-time algorithm to compute the conjugate of (nonconvex) bivariate piecewise linear-quadratic (PLQ) functions (bivariate quadratic functions defined on a polyhedral subdivision). Our algorithm starts with computing the convex envelope of each quadratic piece obtaining rational functions (quadratic over linear) defined over a polyhedral subdivision. Then we compute the conjugate of each resulting piece to obtain piecewise quadratic functions defined over a parabolic subdivision. Finally we compute the maximum of all those functions to obtain the conjugate as a piecewise quadratic function defined on a parabolic subdivision. The resulting algorithm runs in linear time if the initial subdivision is a triangulation (or has a uniform upper bound on the number of vertexes for each piece). Our open-source implementation in MATLAB uses symbolic computation and rational numbers to avoid floating-point errors, and merges pieces as soon as possible to minimize computation time.
title A linear-time algorithm to compute the conjugate of nonconvex bivariate piecewise linear-quadratic functions
topic Optimization and Control
Symbolic Computation
90C25, 65K10, 49M29, 26B25
url https://arxiv.org/abs/2505.06442