A geometrically informed algebraic multigrid preconditioned iterative approach for solving high-order finite element systems

Fuente: arXiv
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Autori principali: Xu, Songzhe, Rasouli, Majid, Kirby, Robert M., Moxey, David, Sundar, Hari
Natura: Preprint
Pubblicazione: 2025
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author Xu, Songzhe
Rasouli, Majid
Kirby, Robert M.
Moxey, David
Sundar, Hari
author_facet Xu, Songzhe
Rasouli, Majid
Kirby, Robert M.
Moxey, David
Sundar, Hari
contents Algebraic multigrid (AMG) is conventionally applied in a black-box fashion, agnostic to the underlying geometry. In this work, we propose that using geometric information -- when available -- to assist with setting up the AMG hierarchy is beneficial, especially for solving linear systems resulting from high-order finite element discretizations. High-order problems draw considerable interest to both the scientific and engineering communities, but lack efficient solvers, at least open-source codes, tailored for unstructured high-order discretizations targeting large-scale, real-world applications. For geometric multigrid, it is known that using p-coarsening before h-coarsening can provide better scalability, but setting up p-coarsening is non-trivial in AMG. We develop a geometrically informed algebraic multigrid (GIAMG) method, as well as an associated high-performance computing program, which is able to set up a grid hierarchy that includes p-coarsening at the top grids with minimal information of the geometry from the user. A major advantage of using p-coarsening with AMG -- beyond the benefits known in the context of geometric multigrid (GMG) -- is the increased sparsification of coarse grid operators. We extensively evaluate GIAMG by testing on the 3D Helmholtz and incompressible flow problems, and demonstrate mesh-independent convergence, and excellent parallel scalability. We also compare the performance of GIAMG with existing AMG packages, including Hypre and ML.
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id arxiv_https___arxiv_org_abs_2512_15121
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A geometrically informed algebraic multigrid preconditioned iterative approach for solving high-order finite element systems
Xu, Songzhe
Rasouli, Majid
Kirby, Robert M.
Moxey, David
Sundar, Hari
Numerical Analysis
Algebraic multigrid (AMG) is conventionally applied in a black-box fashion, agnostic to the underlying geometry. In this work, we propose that using geometric information -- when available -- to assist with setting up the AMG hierarchy is beneficial, especially for solving linear systems resulting from high-order finite element discretizations. High-order problems draw considerable interest to both the scientific and engineering communities, but lack efficient solvers, at least open-source codes, tailored for unstructured high-order discretizations targeting large-scale, real-world applications. For geometric multigrid, it is known that using p-coarsening before h-coarsening can provide better scalability, but setting up p-coarsening is non-trivial in AMG. We develop a geometrically informed algebraic multigrid (GIAMG) method, as well as an associated high-performance computing program, which is able to set up a grid hierarchy that includes p-coarsening at the top grids with minimal information of the geometry from the user. A major advantage of using p-coarsening with AMG -- beyond the benefits known in the context of geometric multigrid (GMG) -- is the increased sparsification of coarse grid operators. We extensively evaluate GIAMG by testing on the 3D Helmholtz and incompressible flow problems, and demonstrate mesh-independent convergence, and excellent parallel scalability. We also compare the performance of GIAMG with existing AMG packages, including Hypre and ML.
title A geometrically informed algebraic multigrid preconditioned iterative approach for solving high-order finite element systems
topic Numerical Analysis
url https://arxiv.org/abs/2512.15121