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In this work, we revisit the adaptive L1 time-stepping scheme for solving the time-fractional Allen-Cahn equation in the Caputo's form. The L1 implicit scheme is shown to preserve a variational energy dissipation law on arbitrary nonuniform…

Numerical Analysis · Mathematics 2023-01-31 Hong-lin Liao , Xiaohan Zhu , Jindi Wang

A fast two-level linearized scheme with unequal time-steps is constructed and analyzed for an initial-boundary-value problem of semilinear subdiffusion equations. The two-level fast L1 formula of the Caputo derivative is derived based on…

Numerical Analysis · Mathematics 2020-12-23 Hong-lin Liao , Yonggui Yan , Jiwei Zhang

We consider difference schemes for the time-fractional diffusion equation with variable coefficients and nonlocal boundary conditions containing real parameters $\alpha$, $\beta$ and $\gamma$. By the method of energy inequalities, for the…

Numerical Analysis · Mathematics 2014-05-02 A. A. Alikhanov

This paper focuses on a nonlinear convection-diffusion equation with space and time-fractional Laplacian operators of orders $1<\beta<2$ and $0<\alpha\leq1$, respectively. We develop local discontinuous Galerkin methods, including Legendre…

Numerical Analysis · Mathematics 2026-02-11 Majid Rajabzadeh , Moein Khalighi

We consider the initial-boundary value problem for a quasilinear time-fractional diffusion equation, and develop a fully discrete solver combining the parareal algorithm in time with a L1 finite-difference approximation of the Caputo…

Numerical Analysis · Mathematics 2025-10-14 Josefa Caballero , Łukasz Płociniczak , Kishin Sadarangani

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

In this paper, we propose and analyze a time-stepping method for the time fractional Allen-Cahn equation. The key property of the proposed method is its unconditional stability for general meshes, including the graded mesh commonly used for…

Numerical Analysis · Mathematics 2021-04-27 Dianming Hou , Chuanju Xu

Can graded meshes yield more accurate numerical solution than uniform meshes? A time-dependent nonlocal diffusion problem with a weakly singular kernel is considered using collocation method. For its steady-state counterpart, under the…

Numerical Analysis · Mathematics 2024-02-01 Minghua Chen , Chao Min , Jiankang Shi , Jizeng Wang

We couple the L1 discretization of the Caputo fractional derivative in time with the Galerkin scheme to devise a linear numerical method for the semilinear subdiffusion equation. Two important points that we make are: nonsmooth initial data…

Numerical Analysis · Mathematics 2025-04-21 Łukasz Płociniczak , Kacper Taźbierski

Lie group method provides an efficient tool to solve a differential equation. This paper suggests a fractional partner for fractional partial differential equations using a fractional characteristic method. A space-time fractional diffusion…

Mathematical Physics · Physics 2010-09-22 Guo-cheng Wu

We prove optimal estimates for the decay in time of solutions to a rather general class of non-local in time subdiffusion equations in $\mathbb{R}^d$. An important special case is the time-fractional diffusion equation, which has seen much…

Analysis of PDEs · Mathematics 2014-03-10 Jukka Kemppainen , Juhana Siljander , Vicente Vergara , Rico Zacher

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

This paper establishes the convergence of a time-steeping scheme for time fractional diffusion problems with nonsmooth data. We first analyze the regularity of the model problem with nonsmooth data, and then prove that the time-steeping…

Numerical Analysis · Mathematics 2018-04-30 Binjie Li , Hao Luo , Xiaoping Xie

Volterra subdiffusion problems with weakly singular kernel describe the dynamics of subdiffusion processes well.The graded $L1$ scheme is often chosen to discretize such problems since it can handle the singularity of the solution near $t =…

Numerical Analysis · Mathematics 2024-03-20 Yong-Liang Zhao , Xian-Ming Gu , Alexander Ostermann

In the present article, we study the diffusion equations with fractional time derivatives. The aim of this paper is to investigate the best possible regularity for the initial value/boundary value problems with non-homogeneous Dirichlet…

Analysis of PDEs · Mathematics 2015-01-08 Kenichi Fujishiro

This paper deals with the multi-term generalisation of the time-fractional diffusion-wave equation for general operators with discrete spectrum, as well as for positive hypoelliptic operators, with homogeneous multi-point time-nonlocal…

Analysis of PDEs · Mathematics 2020-05-05 Michael Ruzhansky , Niyaz Tokmagambetov , Berikbol T. Torebek

We consider the initial/boundary value problem for the fractional diffusion and diffusion-wave equations involving a Caputo fractional derivative in time. We develop two "simple" fully discrete schemes based on the Galerkin finite element…

Numerical Analysis · Mathematics 2015-10-13 Bangti Jin , Raytcho Lazarov , Zhi Zhou

We begin with a treatment of the Caputo time-fractional diffusion equation, by using the Laplace transform, to obtain a Volterra intego-differential equation where we may examine the weakly singular nature of this convolution…

Numerical Analysis · Mathematics 2020-01-27 Wesley Davis , Richard Noren , Ke Shi

We study solution techniques for parabolic equations with fractional diffusion and Caputo fractional time derivative, the latter being discretized and analyzed in a general Hilbert space setting. The spatial fractional diffusion is realized…

Numerical Analysis · Mathematics 2015-03-05 Ricardo H. Nochetto , Enrique Otarola , Abner J. Salgado

We study solution techniques for an evolution equation involving second order derivative in time and the spectral fractional powers, of order $s \in (0,1)$, of symmetric, coercive, linear, elliptic, second-order operators in bounded domains…

Numerical Analysis · Mathematics 2018-06-18 Lehel Banjai , Enrique Otarola