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This paper analyzes a time-stepping discontinuous Galerkin method for fractional diffusion-wave problems. This method uses piecewise constant functions in the temporal discretization and continuous piecewise linear functions in the spatial…

Numerical Analysis · Mathematics 2019-08-27 Binjie Li , Tao Wang , Xiaoping Xie

We propose and analyze a time-stepping discontinuous Petrov-Galerkin method combined with the continuous conforming finite element method in space for the numerical solution of time-fractional subdiffusion problems. We prove the existence,…

Numerical Analysis · Mathematics 2014-09-09 Kassem Mustapha , Basheer Abdallah , Khaled Furati

We consider the initial/boundary value problem for a diffusion equation involving multiple time-fractional derivatives on a bounded convex polyhedral domain. We analyze a space semidiscrete scheme based on the standard Galerkin finite…

Numerical Analysis · Mathematics 2015-06-18 Bangti Jin , Raytcho Lazarov , Yikan Liu , Zhi Zhou

We consider an initial-boundary value problem for $\partial_tu-\partial_t^{-\alpha}\nabla^2u=f(t)$, that is, for a fractional diffusion ($-1<\alpha<0$) or wave ($0<\alpha<1$) equation. A numerical solution is found by applying a…

Numerical Analysis · Mathematics 2016-02-02 Kassem Mustapha , William McLean

In this article we develop an $hp$-adaptive refinement procedure for Trefftz discontinuous Galerkin methods applied to the homogeneous Helmholtz problem. Our approach combines not only mesh subdivision (h-refinement) and local basis…

Numerical Analysis · Mathematics 2017-11-01 Scott Congreve , Paul Houston , Ilaria Perugia

We propose a new geometrically unfitted finite element method based on discontinuous Trefftz ansatz spaces. Trefftz methods allow for a reduction in the number of degrees of freedom in discontinuous Galerkin methods, thereby, the costs for…

Numerical Analysis · Mathematics 2023-10-12 Fabian Heimann , Christoph Lehrenfeld , Paul Stocker , Henry von Wahl

Error estimates are proved for finite element approximations to the solution of second-order hyperbolic partial differential equations with coefficients varying in both space and time. Optimal rates of convergence in the energy norm are…

Numerical Analysis · Mathematics 2026-03-17 Oussama Al Jarroudi , Marcus J. Grote

In this paper a finite difference/local discontinuous Galerkin method for the fractional diffusion-wave equation is presented and analyzed. We first propose a new finite difference method to approximate the time fractional derivatives, and…

Numerical Analysis · Mathematics 2015-07-29 Leilei Wei

We study the use of the hybridizable discontinuous Galerkin (HDG) method for numerically solving fractional diffusion equations of order $-\alpha$ with $-1<\alpha<0$. For exact time-marching, we derive optimal algebraic error estimates…

Numerical Analysis · Mathematics 2014-09-26 Bernardo Cockburn , Kassem Mustapha

We present a hybrid continuous and discontinuous Galerkin spectral element approximation that leverages the advantages of each approach. The continuous Galerkin approximation is used on interior element faces where the equation properties…

Numerical Analysis · Mathematics 2020-12-14 David A. Kopriva , Gregor J. Gassner

Trefftz schemes are high-order Galerkin methods whose discrete spaces are made of elementwise exact solutions of the underlying PDE. Trefftz basis functions can be easily computed for many PDEs that are linear, homogeneous, and have…

Numerical Analysis · Mathematics 2026-03-10 Lise-Marie Imbert-Gérard , Andrea Moiola , Chiara Perinati , Paul Stocker

We propose efficient and parallel algorithms for the implementation of the high-order continuous time Galerkin method for dissipative and wave propagation problems. By using Legendre polynomials as shape functions, we obtain a special…

Numerical Analysis · Mathematics 2023-03-10 Zhiming Chen , Yong Liu

A semidiscrete Galerkin finite element method applied to time-fractional diffusion equations with time-space dependent diffusivity on bounded convex spatial domains will be studied. The main focus is on achieving optimal error results with…

Numerical Analysis · Mathematics 2020-06-12 Kassem Mustapha

A conforming discontinuous Galerkin (DG) finite element method has been introduced in [21] on simplicial meshes, which has the flexibility of using discontinuous approximation and the simplicity in formulation of the classic continuous…

Numerical Analysis · Mathematics 2019-07-11 Xiu Ye , Shangyou Zhang

We introduce an $hp$-version discontinuous Galerkin finite element method (DGFEM) for the linear Boltzmann transport problem. A key feature of this new method is that, while offering arbitrary order convergence rates, it may be implemented…

Numerical Analysis · Mathematics 2024-07-18 Paul Houston , Matthew E. Hubbard , Thomas J. Radley , Oliver J. Sutton , Richard S. J. Widdowson

In the present work, strong approximation errors are analyzed for both the spatial semi-discretization and the spatio-temporal fully discretization of stochastic wave equations (SWEs) with cubic polynomial nonlinearities and additive…

Numerical Analysis · Mathematics 2024-11-08 Ruisheng Qi , Xiaojie Wang

We consider a system of second order non-linear elliptic partial differential equations that models the equilibrium configurations of a two dimensional planar bistable nematic liquid crystal device. Discontinuous Galerkin finite element…

Numerical Analysis · Mathematics 2020-05-29 Ruma Rani Maity , Apala Majumdar , Neela Nataraj

We study the hybridizable discontinuous Galerkin (HDG) method for the spatial discretization of time fractional diffusion models with Caputo derivative of order $0<\alpha<1$. For each time $t \in [0,T]$, the HDG approximations are taken to…

Numerical Analysis · Mathematics 2014-12-08 Kassem Mustapha , Maher Nour , Bernardo Cockburn

A conforming discontinuous Galerkin finite element method is introduced for solving the biharmonic equation. This method, by its name, uses discontinuous approximations and keeps simple formulation of the conforming finite element method at…

Numerical Analysis · Mathematics 2019-07-26 Xiu Ye , Shangyou 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