Dynamical Low-Rank Approximation for Stochastic Differential Equations

Fuente: arXiv
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Autores principales: Kazashi, Yoshihito, Nobile, Fabio, Zoccolan, Fabio
Formato: Preprint
Publicado: 2023
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author Kazashi, Yoshihito
Nobile, Fabio
Zoccolan, Fabio
author_facet Kazashi, Yoshihito
Nobile, Fabio
Zoccolan, Fabio
contents In this paper, we set the mathematical foundations of the Dynamical Low-Rank Approximation (DLRA) method for stochastic differential equations (SDEs). DLRA aims at approximating the solution as a linear combination of a small number of basis vectors with random coefficients (low rank format) with the peculiarity that both the basis vectors and the random coefficients vary in time. While the formulation and properties of DLRA are now well understood for random/parametric equations, the same cannot be said for SDEs and this work aims to fill this gap. We start by rigorously formulating a Dynamically Orthogonal (DO) approximation (an instance of DLRA successfully used in applications) for SDEs, which we then generalize to define a parametrization independent DLRA for SDEs. We show local well-posedness of the DO equations and their equivalence with the DLRA formulation. We also characterize the explosion time of the DO solution by a loss of linear independence of the random coefficients defining the solution expansion and give sufficient conditions for global existence.
format Preprint
id arxiv_https___arxiv_org_abs_2308_11581
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Dynamical Low-Rank Approximation for Stochastic Differential Equations
Kazashi, Yoshihito
Nobile, Fabio
Zoccolan, Fabio
Numerical Analysis
58J65, 60H10, 60H35, 65C30
In this paper, we set the mathematical foundations of the Dynamical Low-Rank Approximation (DLRA) method for stochastic differential equations (SDEs). DLRA aims at approximating the solution as a linear combination of a small number of basis vectors with random coefficients (low rank format) with the peculiarity that both the basis vectors and the random coefficients vary in time. While the formulation and properties of DLRA are now well understood for random/parametric equations, the same cannot be said for SDEs and this work aims to fill this gap. We start by rigorously formulating a Dynamically Orthogonal (DO) approximation (an instance of DLRA successfully used in applications) for SDEs, which we then generalize to define a parametrization independent DLRA for SDEs. We show local well-posedness of the DO equations and their equivalence with the DLRA formulation. We also characterize the explosion time of the DO solution by a loss of linear independence of the random coefficients defining the solution expansion and give sufficient conditions for global existence.
title Dynamical Low-Rank Approximation for Stochastic Differential Equations
topic Numerical Analysis
58J65, 60H10, 60H35, 65C30
url https://arxiv.org/abs/2308.11581