Low-rank-modified Galerkin methods for the Lyapunov equation

Fuente: arXiv
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Autori principali: Lund, Kathryn, Palitta, Davide
Natura: Preprint
Pubblicazione: 2023
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author Lund, Kathryn
Palitta, Davide
author_facet Lund, Kathryn
Palitta, Davide
contents Of all the possible projection methods for solving large-scale Lyapunov matrix equations, Galerkin approaches remain much more popular than minimal-residual ones. This is mainly due to the different nature of the projected problems stemming from these two families of methods. While a Galerkin approach leads to the solution of a low-dimensional matrix equation per iteration, a matrix least-squares problem needs to be solved per iteration in a minimal-residual setting. The significant computational cost of these least-squares problems has steered researchers towards Galerkin methods in spite of the appealing properties of minimal-residual schemes. In this paper we introduce a framework that allows for modifying the Galerkin approach by low-rank, additive corrections to the projected matrix equation problem with the two-fold goal of attaining monotonic convergence rates similar to those of minimal-residual schemes while maintaining essentially the same computational cost of the original Galerkin method. We analyze the well-posedness of our framework and determine possible scenarios where we expect the residual norm attained by two low-rank-modified variants to behave similarly to the one computed by a minimal-residual technique. A panel of diverse numerical examples shows the behavior and potential of our new approach.
format Preprint
id arxiv_https___arxiv_org_abs_2312_00463
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Low-rank-modified Galerkin methods for the Lyapunov equation
Lund, Kathryn
Palitta, Davide
Numerical Analysis
65F45, 65F50, 65F10, 65N22, 65J10
Of all the possible projection methods for solving large-scale Lyapunov matrix equations, Galerkin approaches remain much more popular than minimal-residual ones. This is mainly due to the different nature of the projected problems stemming from these two families of methods. While a Galerkin approach leads to the solution of a low-dimensional matrix equation per iteration, a matrix least-squares problem needs to be solved per iteration in a minimal-residual setting. The significant computational cost of these least-squares problems has steered researchers towards Galerkin methods in spite of the appealing properties of minimal-residual schemes. In this paper we introduce a framework that allows for modifying the Galerkin approach by low-rank, additive corrections to the projected matrix equation problem with the two-fold goal of attaining monotonic convergence rates similar to those of minimal-residual schemes while maintaining essentially the same computational cost of the original Galerkin method. We analyze the well-posedness of our framework and determine possible scenarios where we expect the residual norm attained by two low-rank-modified variants to behave similarly to the one computed by a minimal-residual technique. A panel of diverse numerical examples shows the behavior and potential of our new approach.
title Low-rank-modified Galerkin methods for the Lyapunov equation
topic Numerical Analysis
65F45, 65F50, 65F10, 65N22, 65J10
url https://arxiv.org/abs/2312.00463