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Related papers: Fast multigrid solvers for conforming and non-conf…

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In recent publications, the author and his coworkers have proposed a multigrid method for solving linear systems arizing from the discretization of partial differential equations in isogeometric analysis and have proven that the convergence…

Numerical Analysis · Mathematics 2021-03-05 Stefan Takacs

We consider the linearized elasticity equation, discretized with multi-patch Isogeometric Analysis. A standard discretization error analysis is based on Korn's inequality, which degrades for certain geometries, such as long and thin…

Numerical Analysis · Mathematics 2023-05-10 Jarle Sogn , Stefan Takacs

We propose the first optimal geometric multigrid solver for hybrid high-order discretizations that can handle arbitrary polytopal agglomeration hierarchies in both two and three dimensions. The key ingredient is the use of modified skeleton…

Numerical Analysis · Mathematics 2026-03-03 Santiago Badia , Jordi Manyer

Isogeometric analysis (IGA) is a numerical method that connects computer-aided design (CAD) with finite element analysis (FEA). In CAD the computational domain is usually represented by B-spline or NURBS patches. Given a NURBS…

Numerical Analysis · Mathematics 2023-10-04 Somayeh Kargaran , Bert Jüttler , Thomas Takacs

We consider dual-primal isogeometric tearing and interconnection (IETI-DP) solvers for multi-patch geometries in Isogeometric Analysis. Recently, the authors have published a convergence analysis for those solvers that is explicit in both…

Numerical Analysis · Mathematics 2021-03-09 Rainer Schneckenleitner , Stefan Takacs

In Isogeometric Analysis, the computational domain is often described as multi-patch, where each patch is given by a tensor product spline/NURBS parametrization. In this work we propose a FETI-like solver where local inexact solvers exploit…

Numerical Analysis · Mathematics 2020-09-23 Michal Bosy , Monica Montardini , Giancarlo Sangalli , Mattia Tani

We develop a multigrid solver for the second biharmonic problem in the context of Isogeometric Analysis (IgA), where we also allow a zero-order term. In a previous paper, the authors have developed an analysis for the first biharmonic…

Numerical Analysis · Mathematics 2021-12-24 Jarle Sogn , Stefan Takacs

We present a framework for solving the triharmonic equation over bilinearly parameterized planar multi-patch domains by means of isogeometric analysis. Our approach is based on the construction of a globally $C^2$-smooth isogeometric spline…

Numerical Analysis · Mathematics 2018-08-21 Mario Kapl , Vito Vitrih

We present a novel isogeometric collocation method for solving the Poisson's and the biharmonic equation over planar bilinearly parameterized multi-patch geometries. The proposed approach relies on the use of a modified construction of the…

Numerical Analysis · Mathematics 2024-11-21 Mario Kapl , Aljaž Kosmač , Vito Vitrih

Ill-conditioning of the system matrix is a well-known complication in immersed finite element methods and trimmed isogeometric analysis. Elements with small intersections with the physical domain yield problematic eigenvalues in the system…

Numerical Analysis · Mathematics 2019-12-17 F. de Prenter , C. V. Verhoosel , E. H. van Brummelen , J. A. Evans , C. Messe , J. Benzaken , K. Maute

We present a systematic study on higher-order penalty techniques for isogeometric mortar methods. In addition to the weak-continuity enforced by a mortar method, normal derivatives across the interface are penalized. The considered…

Numerical Analysis · Mathematics 2018-07-04 Thomas Horger , Alessandro Reali , Barbara Wohlmuth , Linus Wunderlich

In isogeometric analysis, isogeometric function spaces are employed for accurately representing the solution to a partial differential equation (PDE) on a parameterized domain. They are generated from a tensor-product spline space by…

Numerical Analysis · Mathematics 2024-03-29 Dany Rios , Felix Scholz , Thomas Takacs

Over the years, Isogeometric Analysis has shown to be a successful alternative to the Finite Element Method (FEM). However, solving the resulting linear systems of equations efficiently remains a challenging task. In this paper, we consider…

Numerical Analysis · Mathematics 2023-07-19 R. Tielen , M. Möller , D. Göddeke , C. Vuik

We present a geometric multigrid solver based on adaptive smoothed aggregation suitable for Discontinuous Galerkin (DG) discretisations. Mesh hierarchies are formed via domain decomposition techniques, and the method is applicable to fully…

Numerical Analysis · Mathematics 2025-06-02 Yulong Pan , Michael Lindsey , Per-Olof Persson

Isogeometric analysis (IgA) offers enhanced approximation capabilities for the discretization of elliptic boundary-value problems, yet it results in large, sparse, and increasingly ill-conditioned linear systems due to higher…

Numerical Analysis · Mathematics 2026-05-01 Pasqua D'Ambra , Fabio Durastante , Salvatore Filippone

One key feature of isogeometric analysis is that it allows smooth shape functions. Indeed, when isogeometric spaces are constructed from $p$-degree splines (and extensions, such as NURBS), they enjoy up to $C^{p-1}$ continuity within each…

Numerical Analysis · Mathematics 2016-05-10 Annabelle Collin , Giancarlo Sangalli , Thomas Takacs

We present an isogeometric mortar method for the discretization of the biharmonic equation posed on multi-patch domains. We assume only $C^0$-conformity at interfaces and employs a mortar approach to weakly enforce $C^1$-continuity across…

Numerical Analysis · Mathematics 2025-10-08 Andrea Benvenuti , Gabriele Loli , Giancarlo Sangalli , Thomas Takacs

We propose and analyze a domain decomposition solver for the biharmonic problem. The problem is discretized in a conforming way using multi-patch Isogeometric Analysis. As first step, we discuss the setup of a sufficiently smooth…

Numerical Analysis · Mathematics 2025-11-10 Stefan Takacs

In the context of isogeometric analysis, we consider two discretization approaches that make the resulting stiffness matrix nonsymmetric even if the differential operator is self-adjoint. These are the collocation method and the…

Numerical Analysis · Mathematics 2017-05-15 Mattia Tani

We prove $p$-robust approximation error estimates for $H^2$-conforming isogeometric discretizations over planar multi-patch domains. Possible applications are fourth order boundary value problems, like the biharmonic equation or…

Numerical Analysis · Mathematics 2026-05-14 Fatima Hasanova , Stefan Takacs , Thomas Takacs