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We propose and analyze novel adaptive algorithms for the numerical solution of elliptic partial differential equations with parametric uncertainty. Four different marking strategies are employed for refinement of stochastic Galerkin finite…

Numerical Analysis · Mathematics 2019-10-08 Alex Bespalov , Dirk Praetorius , Leonardo Rocchi , Michele Ruggeri

We study a recent timestep adaptation technique for hyperbolic conservation laws. The key tool is a space-time splitting of adjoint error representations for target functionals due to S\"uli and Hartmann. It provides an efficient choice of…

Numerical Analysis · Mathematics 2014-05-27 Christina Steiner , Sebastian Noelle

The convergence of an adaptive mixed finite element method for general second order linear elliptic problems defined on simply connected bounded polygonal domains is analyzed in this paper. The main difficulties in the analysis are posed by…

Numerical Analysis · Mathematics 2014-02-14 Asha K. Dond , Neela Nataraj , Amiya K. Pani

Fractional differential equations provide a tractable mathematical framework to describe anomalous behavior in complex physical systems, yet they introduce new sensitive model parameters, i.e. derivative orders, in addition to model…

Numerical Analysis · Mathematics 2018-06-05 Ehsan Kharazmi , Mohsen Zayernouri

This paper presents a hybridized formulation for the weak Galerkin finite element method for the biharmonic equation. The hybridized weak Galerkin scheme is based on the use of a Lagrange multiplier defined on the element boundaries. The…

Numerical Analysis · Mathematics 2014-02-06 Chunmei Wang , Junping Wang

Inverse design has greatly expanded nanophotonic devices and brought optimized performance. However, the use of inverse design for plasmonic structures has been challenging due to local field concentrations that can lead to errors in…

Computational Physics · Physics 2020-12-14 Zhou Zeng , Xianfan Xu

We propose a novel class of temporal high-order parametric finite element methods for solving a wide range of geometric flows of curves and surfaces. By incorporating the backward differentiation formulae (BDF) for time discretization into…

Numerical Analysis · Mathematics 2024-08-21 Wei Jiang , Chunmei Su , Ganghui Zhang

We consider the damped time-harmonic Galbrun's equation, which is used to model stellar oscillations. We introduce a discontinuous Galerkin finite element method (DGFEM) with $H(\operatorname{div})$-elements, which is nonconform with…

Numerical Analysis · Mathematics 2023-06-07 Martin Halla

In this paper we consider the inverse problem of identifying the initial data in a fractionally damped wave equation from time trace measurements on a surface, as relevant in photoacoustic or thermoacoustic tomography. We derive and analyze…

Numerical Analysis · Mathematics 2021-11-24 Barbara Kaltenbacher , Anna Schlintl

In this article we develop a convergence theory for goal-oriented adaptive finite element algorithms designed for a class of second-order semilinear elliptic equations. We briefly discuss the target problem class, and introduce several…

Numerical Analysis · Mathematics 2014-04-24 Michael Holst , Sara Pollock , Yunrong Zhu

In the present paper, we consider large-scale differential Lyapunov matrix equations having a low rank constant term. We present two new approaches for the numerical resolution of such differential matrix equations. The first approach is…

Numerical Analysis · Mathematics 2017-05-30 M. Hached , K. Jbilou

This paper presents and analyzes a parallelizable iterative procedure based on domain decomposition for primal-dual weak Galerkin (PDWG) finite element methods applied to the Poisson equation. The existence and uniqueness of the PDWG…

Numerical Analysis · Mathematics 2024-07-02 Chunmei Wang , Junping Wang

In this work, we propose and develop an arbitrary-order adaptive discontinuous Petrov-Galerkin (DPG) method for the nonlinear Grad-Shafranov equation. An ultraweak formulation of the DPG scheme for the equation is given based on a minimal…

Numerical Analysis · Mathematics 2020-07-14 Zhichao Peng , Qi Tang , Xian-Zhu Tang

We devise the fast adjoint response algorithm for the gradient of physical measures (long-time-average statistics) of discrete-time hyperbolic chaos with respect to many system parameters. Its cost is independent of the number of…

Dynamical Systems · Mathematics 2022-09-13 Angxiu Ni

We propose and analyze a finite element method for a semi-stationary Stokes system modeling compressible fluid flow subject to a Navier-slip boundary condition. The velocity (momentum) equation is approximated by a mixed finite element…

Numerical Analysis · Mathematics 2009-04-07 Kenneth H. Karlsen , Trygve K. Karper

We propose a variational form of the BDF2 method as an alternative to the commonly used minimizing movement scheme for the time-discrete approximation of gradient flows in abstract metric spaces. Assuming uniform semi-convexity --- but no…

Analysis of PDEs · Mathematics 2017-12-25 Daniel Matthes , Simon Plazotta

This paper introduces a numerical scheme for time harmonic Maxwell's equations by using weak Galerkin (WG) finite element methods. The WG finite element method is based on two operators: discrete weak curl and discrete weak gradient, with…

Numerical Analysis · Mathematics 2013-12-10 Lin Mu , Junping Wang , Xiu Ye , Shangyou Zhang

Diffusion approximation provides weak approximation for stochastic gradient descent algorithms in a finite time horizon. In this paper, we introduce new tools motivated by the backward error analysis of numerical stochastic differential…

Machine Learning · Computer Science 2019-09-05 Yuanyuan Feng , Tingran Gao , Lei Li , Jian-Guo Liu , Yulong Lu

This paper considers a class of structured fractional minimization problems. The numerator consists of a differentiable function, a simple nonconvex nonsmooth function, a concave nonsmooth function, and a convex nonsmooth function composed…

Optimization and Control · Mathematics 2025-04-01 Ganzhao Yuan

The generalized weak Galerkin (gWG) finite element method is proposed and analyzed for the biharmonic equation. A new generalized discrete weak second order partial derivative is introduced in the gWG scheme to allow arbitrary combinations…

Numerical Analysis · Mathematics 2023-02-14 Dan Li , Chunmei Wang , Junping Wang
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