Space-Time Block Preconditioning for Incompressible Resistive Magnetohydrodynamics

Fuente: arXiv
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Autores principales: Danieli, Federico, Southworth, Ben S., Schroder, Jacob B.
Formato: Preprint
Publicado: 2023
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author Danieli, Federico
Southworth, Ben S.
Schroder, Jacob B.
author_facet Danieli, Federico
Southworth, Ben S.
Schroder, Jacob B.
contents This work develops an all-at-once space-time preconditioning approach for resistive magnetohydrodynamics (MHD). We consider parallel-in-time due to the long time domains required to capture the physics of interest, as well as the complexity of the underlying system and thereby computational cost of long-time integration. To ameliorate this cost by using many processors, we thus develop a novel approach to solving the whole space-time system that is parallelizable in both space and time. We develop a space-time block preconditioning for resistive MHD, following the space-time block preconditioning concept first introduced by Danieli et al. in 2022 for incompressible flow, where an effective preconditioner for classic sequential time-stepping is extended to the space-time setting. The starting point for our derivation is the continuous Schur complement preconditioner by Cyr et al. in 2021, which we proceed to generalise in order to produce, to our knowledge, the first space-time block preconditioning approach for the challenging equations governing incompressible resistive MHD. The numerical results are promising for the model problems of island coalescence and tearing mode, which we investigate numerically in a mixed regime, where advective and diffusive forces are both present. The overhead computational cost associated with space-time preconditioning versus sequential time-stepping is modest and primarily in the range of 2x-5x, which is low for parallel-in-time schemes in general. Additionally, the scaling results for inner (linear) and outer (nonlinear) iterations are flat in the case of fixed time-step size and only grow very slowly in the case of time-step refinement.
format Preprint
id arxiv_https___arxiv_org_abs_2309_00768
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Space-Time Block Preconditioning for Incompressible Resistive Magnetohydrodynamics
Danieli, Federico
Southworth, Ben S.
Schroder, Jacob B.
Numerical Analysis
65F08, 65Y05, 76W05, 65M60, 65M22
This work develops an all-at-once space-time preconditioning approach for resistive magnetohydrodynamics (MHD). We consider parallel-in-time due to the long time domains required to capture the physics of interest, as well as the complexity of the underlying system and thereby computational cost of long-time integration. To ameliorate this cost by using many processors, we thus develop a novel approach to solving the whole space-time system that is parallelizable in both space and time. We develop a space-time block preconditioning for resistive MHD, following the space-time block preconditioning concept first introduced by Danieli et al. in 2022 for incompressible flow, where an effective preconditioner for classic sequential time-stepping is extended to the space-time setting. The starting point for our derivation is the continuous Schur complement preconditioner by Cyr et al. in 2021, which we proceed to generalise in order to produce, to our knowledge, the first space-time block preconditioning approach for the challenging equations governing incompressible resistive MHD. The numerical results are promising for the model problems of island coalescence and tearing mode, which we investigate numerically in a mixed regime, where advective and diffusive forces are both present. The overhead computational cost associated with space-time preconditioning versus sequential time-stepping is modest and primarily in the range of 2x-5x, which is low for parallel-in-time schemes in general. Additionally, the scaling results for inner (linear) and outer (nonlinear) iterations are flat in the case of fixed time-step size and only grow very slowly in the case of time-step refinement.
title Space-Time Block Preconditioning for Incompressible Resistive Magnetohydrodynamics
topic Numerical Analysis
65F08, 65Y05, 76W05, 65M60, 65M22
url https://arxiv.org/abs/2309.00768