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For the solution of discrete ill-posed problems, in this paper a novel preconditioned iterative method based on the Arnoldi algorithm for matrix functions is presented. The method is also extended to work in connection with Tikhonov…

Numerical Analysis · Mathematics 2011-11-18 Paolo Novati , Michela Redivo-Zaglia , Maria Rosaria Russo

We consider systems of nonlinear magnetostatics and quasistatics that typically arise in the modeling and simulation of electric machines. The nonlinear problems, eventually obtained after time discretization, are usually solved by…

Numerical Analysis · Mathematics 2023-11-27 Herbert Egger , Felix Engertsberger , Bogdan Radu

In this paper, we propose fast solvers for Maxwell's equations in rectangular domains. We first discretize the simplified Maxwell's eigenvalue problems by employing the lowest-order rectangular N\'ed\'elec elements and derive the discrete…

Numerical Analysis · Mathematics 2025-03-14 Lixiu Wang , Lueling Jia , Zijian Cao , Huiyuan Li , Zhimin Zhang

We prove sharp wavenumber-explicit error bounds for first- or second-family-N\'ed\'elec-element (a.k.a. edge-element) conforming discretisations, of arbitrary (fixed) order, of the variable-coefficient time-harmonic Maxwell equations posed…

Numerical Analysis · Mathematics 2026-01-09 Théophile Chaumont-Frelet , Jeffrey Galkowski , Euan A. Spence

The Legendre spectral Galerkin method of self-adjoint second order elliptic equations usually results in a linear system with a dense and ill-conditioned coefficient matrix. In this paper, the linear system is solved by a preconditioned…

Numerical Analysis · Mathematics 2020-04-30 Xuhao Diao , Jun Hu , Suna Ma

We consider residual-based a posteriori error estimators for Galerkin-type discretizations of time-harmonic Maxwell's equations. We focus on configurations where the frequency is high, or close to a resonance frequency, and derive…

Numerical Analysis · Mathematics 2022-08-03 T. Chaumont-Frelet , P. Vega

To precondition a large and sparse linear system, two direct methods for approximate factoring of the inverse are devised. The algorithms are fully parallelizable and appear to be more robust than the iterative methods suggested for the…

Numerical Analysis · Mathematics 2012-08-20 Mikko Byckling , Marko Huhtanen

The performance of finite element solvers on modern computer architectures is typically memory bound for sufficiently large problems. The main cause for this is that loading matrix elements from RAM into CPU cache is significantly slower…

Numerical Analysis · Mathematics 2019-05-01 Denis Davydov , Jean-Paul Pelteret , Daniel Arndt , Paul Steinmann

We describe a fourth-order accurate finite-difference time-domain scheme for solving dispersive Maxwell's equations with nonlinear multi-level carrier kinetics models. The scheme is based on an efficient single-step three time-level…

We consider a lowest-order finite element discretization of the nonlinear system of Maxwell's and Landau-Lifshitz-Gilbert equations (MLLG). Two algorithms are proposed to numerically solve this problem, both of which only require the…

Numerical Analysis · Mathematics 2017-01-30 L'ubomir Banas , Marcus Page , Dirk Praetorius

This article deals with the study of electromagnetic waves equations and the Lorentz condition, as emergent properties of Maxwell's system in the context of systems theory. To do this, the wave equations and the Helmholtz equation are first…

Classical Physics · Physics 2020-10-28 Yudier Peña Pérez , Juan Bory Reyes

We review our recent work leading to steady-state solutions of the semiclassical (Maxwell-Bloch) equations of a laser. These are coupled non-linear partial differential equations in space and time which have previously been solved either by…

In recent years there have been tremendous advances in the theoretical understanding of boundary integral equations for Maxwell problems. In particular, stable dual pairing of discretisation spaces have been developed that allow robust…

Numerical Analysis · Mathematics 2020-05-14 Matthew Scroggs , Timo Betcke , Erik Burman , Wojciech Śmigaj , Elwin van 't Wout

We consider the approximation of the inverse of the finite element stiffness matrix in the data sparse $\mathcal{H}$-matrix format. For a large class of shape regular but possibly non-uniform meshes including graded meshes, we prove that…

Numerical Analysis · Mathematics 2024-07-25 Niklas Angleitner , Markus Faustmann , Jens Markus Melenk

A finite element method for the solution of the time-dependent Maxwell equations in mixed form is presented. The method allows for local $hp$-refinement in space and in time. To this end, a space-time Galerkin approach is employed. In…

Numerical Analysis · Mathematics 2014-12-18 Martin Lilienthal , Sascha M. Schnepp , Thomas Weiland

We propose a preconditioner to accelerate the convergence of the GMRES iterative method for solving the system of linear equations obtained from discretize-then-optimize approach applied to optimal control problems constrained by a partial…

Numerical Analysis · Mathematics 2019-11-15 Hamid Mirchi , Davod Khojasteh Salkuyeh

In this paper, we propose a new finite element approach to simulate the time-dependent Ginzburg-Landau equations under the temporal gauge, and design an efficient preconditioner for the Newton iteration of the resulting discrete system. The…

Numerical Analysis · Mathematics 2022-12-28 Qingguo Hong , Limin Ma , Jinchao Xu

We consider the time-harmonic Maxwell equations with impedance boundary conditions on a bounded Lipschitz domain $\Omega$ with analytic boundary $\Gamma$. We suppose that $\Omega$ consists of multiple subdomains, and that the permeability…

Numerical Analysis · Mathematics 2026-03-19 Jens Markus Melenk , David Wörgötter

The discretization of the double-layer potential integral equation for the interior Dirichlet Laplace problem in a domain with smooth boundary results in a linear system that has a bounded condition number. Thus, the number of iterations…

Numerical Analysis · Mathematics 2014-02-27 Bryan Quaife , George Biros

We study the time harmonic Maxwell equations in a meta-material consisting of perfect conductors and void space. The meta-material is assumed to be periodic with period $\eta > 0$; we study the behaviour of solutions $(E^{\eta}, H^{\eta})$…

Analysis of PDEs · Mathematics 2017-03-17 Ben Schweizer , Maik Urban