A data driven Koopman-Schur decomposition for computational analysis of nonlinear dynamics

Fuente: arXiv
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Main Authors: Drmač, Zlatko, Mezić, Igor
Format: Preprint
Published: 2023
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_version_ 1866916393059876864
author Drmač, Zlatko
Mezić, Igor
author_facet Drmač, Zlatko
Mezić, Igor
contents This paper introduces a new theoretical and computational framework for a data driven Koopman mode analysis of nonlinear dynamics. To alleviate the potential problem of ill-conditioned eigenvectors in the existing implementations of the Dynamic Mode Decomposition (DMD) and the Extended Dynamic Mode Decomposition (EDMD), the new method introduces a Koopman-Schur decomposition that is entirely based on unitary transformations. The analysis in terms of the eigenvectors as modes of a Koopman operator compression is replaced with a modal decomposition in terms of a flag of invariant subspaces that correspond to selected eigenvalues. The main computational tool from the numerical linear algebra is the partial ordered Schur decomposition that provides convenient orthonormal bases for these subspaces. In the case of real data, a real Schur form is used and the computation is based on real orthogonal transformations. The new computational scheme is presented in the framework of the Extended DMD and the kernel trick is used.
format Preprint
id arxiv_https___arxiv_org_abs_2312_15837
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A data driven Koopman-Schur decomposition for computational analysis of nonlinear dynamics
Drmač, Zlatko
Mezić, Igor
Numerical Analysis
37N30, 65P99, 37M05, 37M25
G.1.3; G.1.7; G.1.10
This paper introduces a new theoretical and computational framework for a data driven Koopman mode analysis of nonlinear dynamics. To alleviate the potential problem of ill-conditioned eigenvectors in the existing implementations of the Dynamic Mode Decomposition (DMD) and the Extended Dynamic Mode Decomposition (EDMD), the new method introduces a Koopman-Schur decomposition that is entirely based on unitary transformations. The analysis in terms of the eigenvectors as modes of a Koopman operator compression is replaced with a modal decomposition in terms of a flag of invariant subspaces that correspond to selected eigenvalues. The main computational tool from the numerical linear algebra is the partial ordered Schur decomposition that provides convenient orthonormal bases for these subspaces. In the case of real data, a real Schur form is used and the computation is based on real orthogonal transformations. The new computational scheme is presented in the framework of the Extended DMD and the kernel trick is used.
title A data driven Koopman-Schur decomposition for computational analysis of nonlinear dynamics
topic Numerical Analysis
37N30, 65P99, 37M05, 37M25
G.1.3; G.1.7; G.1.10
url https://arxiv.org/abs/2312.15837