Error estimates for the discretization of bilinear control problems governed by semilinear elliptic PDEs

Fuente: arXiv
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Auteurs principaux: Casas, Eduardo, Chrysafinos, Konstantinos, Mateos, Mariano
Format: Preprint
Publié: 2024
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author Casas, Eduardo
Chrysafinos, Konstantinos
Mateos, Mariano
author_facet Casas, Eduardo
Chrysafinos, Konstantinos
Mateos, Mariano
contents This paper studies an optimal control problem governed by a semilinear elliptic equation, in which the control acts in a multiplicative or bilinear way as the reaction coefficient of the equation. We focus on the numerical discretization of the problem. The discretization is carried out by using the finite element method, with piecewise constant functions for the control and continuous piecewise linear functions for the state and the adjoint state. We first prove convergence of the solutions of the discrete problems to solutions of the continuous problem. We also demonstrate that strict local solutions of the continuous problem can be approximated by local solutions of the discrete problems. Next we obtain an error estimate of order $O(h)$ for the difference between continuous and discrete locally optimal controls. To obtain this result we assume no-gap second order sufficient optimality conditions. As it is usual in this kind of discretization, a superconvergence phenomenon of order $O(h^2)$ is observed in numerical experiments for the error estimates of the state and adjoint state. The last part of the paper is dedicated to explain this behaviour. A numerical experiment confirming these results is included.
format Preprint
id arxiv_https___arxiv_org_abs_2404_05658
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Error estimates for the discretization of bilinear control problems governed by semilinear elliptic PDEs
Casas, Eduardo
Chrysafinos, Konstantinos
Mateos, Mariano
Optimization and Control
65N30, 49M25, 35J61
This paper studies an optimal control problem governed by a semilinear elliptic equation, in which the control acts in a multiplicative or bilinear way as the reaction coefficient of the equation. We focus on the numerical discretization of the problem. The discretization is carried out by using the finite element method, with piecewise constant functions for the control and continuous piecewise linear functions for the state and the adjoint state. We first prove convergence of the solutions of the discrete problems to solutions of the continuous problem. We also demonstrate that strict local solutions of the continuous problem can be approximated by local solutions of the discrete problems. Next we obtain an error estimate of order $O(h)$ for the difference between continuous and discrete locally optimal controls. To obtain this result we assume no-gap second order sufficient optimality conditions. As it is usual in this kind of discretization, a superconvergence phenomenon of order $O(h^2)$ is observed in numerical experiments for the error estimates of the state and adjoint state. The last part of the paper is dedicated to explain this behaviour. A numerical experiment confirming these results is included.
title Error estimates for the discretization of bilinear control problems governed by semilinear elliptic PDEs
topic Optimization and Control
65N30, 49M25, 35J61
url https://arxiv.org/abs/2404.05658