A Parareal Algorithm with Low-Rank Coarse Solvers

Fuente: arXiv
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Autori principali: Gander, Martin J., Ohlberger, Mario, Rave, Stephan
Natura: Preprint
Pubblicazione: 2025
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author Gander, Martin J.
Ohlberger, Mario
Rave, Stephan
author_facet Gander, Martin J.
Ohlberger, Mario
Rave, Stephan
contents We consider a new class of Parareal algorithms, which use ideas from localized reduced basis methods to construct the coarse solver from truncated SVD approximations of the transfer operators mapping initial values for a given time interval to the solution at the end of the interval. By leveraging randomized singular value decompositions, these low-rank approximations are obtained embarrassingly parallel by computing local fine solutions for random initial values. We show a priori and a posteriori error bounds in terms of the computed singular values of the transfer operators. Our numerical experiments demonstrate that our approach can significantly outperform Parareal with single-step coarse solvers. At the same time, it permits to further increase parallelism in Parareal by trading global iterations for a larger number of independent local solves.
format Preprint
id arxiv_https___arxiv_org_abs_2508_08873
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Parareal Algorithm with Low-Rank Coarse Solvers
Gander, Martin J.
Ohlberger, Mario
Rave, Stephan
Numerical Analysis
65M20, 65M55, 65Y05, 65Y20
We consider a new class of Parareal algorithms, which use ideas from localized reduced basis methods to construct the coarse solver from truncated SVD approximations of the transfer operators mapping initial values for a given time interval to the solution at the end of the interval. By leveraging randomized singular value decompositions, these low-rank approximations are obtained embarrassingly parallel by computing local fine solutions for random initial values. We show a priori and a posteriori error bounds in terms of the computed singular values of the transfer operators. Our numerical experiments demonstrate that our approach can significantly outperform Parareal with single-step coarse solvers. At the same time, it permits to further increase parallelism in Parareal by trading global iterations for a larger number of independent local solves.
title A Parareal Algorithm with Low-Rank Coarse Solvers
topic Numerical Analysis
65M20, 65M55, 65Y05, 65Y20
url https://arxiv.org/abs/2508.08873