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We study a multigrid method for solving large linear systems of equations with tensor product structure. Such systems are obtained from stochastic finite element discretization of stochastic partial differential equations such as the…

Numerical Analysis · Mathematics 2017-04-11 Howard C. Elman , Tengfei Su

This work deals with the efficient numerical solution of the time-fractional heat equation discretized on non-uniform temporal meshes. Non-uniform grids are essential to capture the singularities of "typical" solutions of time-fractional…

Numerical Analysis · Mathematics 2020-05-08 Xiaozhe Hu , Carmen Rodrigo , Francisco J. Gaspar

Due to the wide separation of time scales in geophysical fluid dynamics, semi-implicit time integrators are commonly used in operational atmospheric forecast models. They guarantee the stable treatment of fast (acoustic and gravity) waves,…

Computational Physics · Physics 2020-12-30 Christopher Maynard , Thomas Melvin , Eike Hermann Müller

Having in mind the modelling of marble degradation under chemical pollutants, e.g.~the sulfation process, we consider governing nonlinear diffusion equations and their numerical approximation.The space domain of a computation is the…

Numerical Analysis · Mathematics 2020-10-29 Armando Coco , Matteo Semplice , Stefano Serra-Capizzano

In this paper we want to propose practical numerical methods to solve a class of initial-boundary problem of space-time fractional advection-diffusion equations. To start with, an implicit method based on two-sided Gr\"unwald formulae is…

Numerical Analysis · Mathematics 2016-06-22 Zhi Zhao , Xiao-Qing Jin , Matthew M. Lin

Non-hydrostatic atmospheric models often use semi-implicit temporal discretisations in order to negate the time step limitation of explicitly resolving the fast acoustic and gravity waves. Solving the resulting system to machine precision…

Atmospheric and Oceanic Physics · Physics 2023-09-04 David Lee

L\'{e}vy flight models whose jumps have infinite moments are mathematically used to describe the superdiffusion in complex systems. Exponentially tempering the Levy measure of L\'{e}vy flights leads to the tempered stable L\'{e}vy processes…

Computational Physics · Physics 2016-05-19 Can Li , Weihua Deng

A new method is formulated and analyzed for the approximate solution of a two-dimensional time-fractional diffusion-wave equation. In this method, orthogonal spline collocation is used for the spatial discretization and, for the…

Numerical Analysis · Mathematics 2014-05-14 Graeme Fairweather , Xuehua Yang , Da Xu , Haixiang Zhang

We consider a recently introduced formulation for fluid-structure interaction problems which makes use of a distributed Lagrange multiplier in the spirit of the fictitious domain method. In this paper we focus on time integration methods of…

Numerical Analysis · Mathematics 2019-07-02 Daniele Boffi , Lucia Gastaldi , Sebastian Wolf

Efficient and energy stable high order time marching schemes are very important but not easy to construct for the study of nonlinear phase dynamics. In this paper, we propose and study two linearly stabilized second order semi-implicit…

Numerical Analysis · Mathematics 2019-09-04 Lin Wang , Haijun Yu

This article devotes to developing robust but simple correction techniques and efficient algorithms for a class of second-order time stepping methods, namely the shifted fractional trapezoidal rule (SFTR), for subdiffusion problems to…

Numerical Analysis · Mathematics 2020-10-26 Baoli Yin , Yang Liu , Hong Li , Zhimin Zhang

In the present paper we propose a coupled multigrid method for generalized Stokes flow problems. Such problems occur as subproblems in implicit time-stepping approaches for time-dependent Stokes problems. The discretized Stokes system is a…

Numerical Analysis · Mathematics 2016-01-08 Stefan Takacs

In the continuous time random walk model, the time-fractional operator usually expresses an infinite waiting time probability density. Different from that usual setting, this work considers the tempered time-fractional operator, which…

Numerical Analysis · Mathematics 2021-12-16 Libo Feng , Fawang Liu , Vo V. Anh , Shanlin Qin

We investigate a second-order accurate time-stepping scheme for solving a time-fractional diffusion equation with a Caputo derivative of order~$\alpha \in (0,1)$. The basic idea of our scheme is based on local integration followed by linear…

Numerical Analysis · Mathematics 2024-07-10 Kassem Mustapha , William McLean , Josef Dick

We expand the applicabilities and capabilities of an already existing space-time parallel method based on a block Jacobi smoother. First we formulate a more detailed criterion for spatial coarsening, which enables the method to deal with…

Computational Engineering, Finance, and Science · Computer Science 2019-11-22 Martin Neumüller , Martin Schwalsberger

An implicit method for the ohmic dissipation is proposed. The proposed method is based on the Crank-Nicolson method and exhibits second-order accuracy in time and space. The proposed method has been implemented in the SFUMATO adaptive mesh…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Tomoaki Matsumoto

The paper investigates a non-intrusive parallel time integration with multigrid for space-fractional diffusion equations in two spatial dimensions. We firstly obtain a fully discrete scheme via using the linear finite element method to…

Numerical Analysis · Mathematics 2018-05-18 Xiaoqiang Yue , Shi Shu , Xiaowen Xu , Weiping Bu , Kejia Pan

In this paper, a new type of the discrete fractional Gr{\"o}nwall inequality is developed, which is applied to analyze the stability and convergence of a Galerkin spectral method for a linear time-fractional subdiffusion equation. Based on…

Numerical Analysis · Mathematics 2024-12-20 Yubo Yang , Fanhai Zeng

This article presents a finite element scheme with Newton's method for solving the time-fractional nonlinear diffusion equation. For time discretization, we use the fractional Crank-Nicolson scheme based on backward Euler convolution…

Analysis of PDEs · Mathematics 2018-11-26 Dileep Kumar , Sudhakar Chaudhary , V. V. K Srinivas Kumar

In this paper, we study temporal splitting algorithms for multiscale problems. The exact fine-grid spatial problems typically require some reduction in degrees of freedom. Multiscale algorithms are designed to represent the fine-scale…

Numerical Analysis · Mathematics 2021-06-02 Yalchin Efendiev , Sai-Mang Pun , Petr N. Vabishchevich