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The paper focuses on numerical solution of parametrized diffusion equations with scalar parameter-dependent coefficient function by the stochastic (spectral) Galerkin method. We study preconditioning of the related discretized problems…

Numerical Analysis · Mathematics 2020-01-20 Marie Kubínová , Ivana Pultarová

A spatially localized initial condition for an energy-conserving wave equation with periodic coefficients disperses (spatially spreads) and decays in amplitude as time advances. This dispersion is associated with the continuous spectrum of…

Mathematical Physics · Physics 2021-10-01 Vincent Duchêne , Iva Vukićević , Michael I. Weinstein

In this paper, we consider Caputo type fractional stochastic time-delay system with permutable matrices. We derive stochastic analogue of variation of constants formula via a newly defined delayed Mittag-Leffer type matrix function. Thus,…

Dynamical Systems · Mathematics 2020-09-23 Arzu Ahmadova , Ismail T. Huseynov , Nazim I. Mahmudov

Based on the weighted and shifted Gr\"{u}nwald difference (WSGD) operators [24], we further construct the compact finite difference discretizations for the fractional operators. Then the discretization schemes are used to approximate the…

Numerical Analysis · Mathematics 2014-01-30 Han Zhou , WenYi Tian , Weihua Deng

This paper presents the continuous and discrete variational formulations of simple thermodynamical systems whose configuration space is a (finite dimensional) Lie group. We follow the variational approach to nonequilibrium thermodynamics…

Dynamical Systems · Mathematics 2018-06-27 Benjamin Couéraud , François Gay-Balmaz

The finite-difference time-domain (FDTD) method is applied for modelling of wire media as artificial dielectrics. Both frequency dispersion and spatial dispersion effects in wire media are taken into account using the auxiliary differential…

Materials Science · Physics 2009-11-11 Yan Zhao , Pavel Belov , Yang Hao

We make the first steps towards diffusion models for unconditional generation of multivariate and Arctic-wide sea-ice states. While targeting to reduce the computational costs by diffusion in latent space, latent diffusion models also offer…

Machine Learning · Computer Science 2024-07-23 Tobias Sebastian Finn , Charlotte Durand , Alban Farchi , Marc Bocquet , Julien Brajard

This paper investigates the following question: given a Galerkin matrix corresponding to a finite-element discretisation of either the Helmholtz or time-harmonic Maxwell equations with variable coefficients, suppose that the coefficients of…

Numerical Analysis · Mathematics 2026-01-15 Euan A. Spence

The discrete complex Ginzburg-Landau equation is a fundamental model for the dynamics of nonlinear lattices incorporating competitive dissipation and energy gain effects. Such mechanisms are of particular importance for the study of…

Pattern Formation and Solitons · Physics 2023-05-03 Dirk Hennig , Nikos I. Karachalios , Jesús Cuevas-Maraver

The conditioning of the linear finite volume element discretization for general diffusion equations is studied on arbitrary simplicial meshes. The condition number is defined as the ratio of the maximal singular value of the stiffness…

Numerical Analysis · Mathematics 2020-04-20 Xiang Wang , Weizhang Huang , Yonghai Li

In this work, we consider a FDE (fractional diffusion equation) $${}^C D_t^\alpha u(x,t)-a(t)\mathcal{L} u(x,t)=F(x,t)$$ with a time-dependent diffusion coefficient $a(t)$. For the direct problem, given an $a(t),$ we establish the…

Analysis of PDEs · Mathematics 2019-04-08 Zhidong Zhang

We present a discretization of the linear advection of differential forms on bounded domains. The framework previously established is extended to incorporate the Lie derivative, $\mathcal L$, by means of Cartan's homotopy formula. The…

Numerical Analysis · Mathematics 2013-04-26 Artur Palha , Pedro Pinto Rebelo , Marc Gerritsma

This work deals with the isogeometric Galerkin discretization of the eigenvalue problem related to the Laplace operator subject to homogeneous Dirichlet boundary conditions on bounded intervals. This paper uses GLT theory to study the…

Numerical Analysis · Mathematics 2024-01-05 N. Lamsahel , A. El Akri , A. Ratnani

The paper focuses on developing and studying efficient block preconditioners based on classical algebraic multigrid for the large-scale sparse linear systems arising from the fully coupled and implicitly cell-centered finite volume…

Numerical Analysis · Mathematics 2021-02-03 Xiaoqiang Yue , Shulei Zhang , Xiaowen Xu , Shi Shu , Weidong Shi

Prior to the parallel solution of a large linear system, it is required to perform a partitioning of its equations/unknowns. Standard partitioning algorithms are designed using the considerations of the efficiency of the parallel…

Numerical Analysis · Mathematics 2013-11-19 Eugene Vecharynski , Yousef Saad , Masha Sosonkina

Obtaining stable diffusion-based samplers in high- and infinite-dimensional settings is challenging because errors can accumulate across high-frequency coordinates and make the dynamics unstable under refinement of the finite-dimensional…

Machine Learning · Statistics 2026-05-19 Lorenzo Baldassari , Josselin Garnier , Knut Solna , Maarten V. de Hoop

We present a solution of the full TDDFT eigenvalue equation in the linear response formalism exhibiting a linear-scaling computational complexity with system size, without relying on the simplifying Tamm-Dancoff approximation (TDA). The…

Computational Physics · Physics 2016-01-20 Tim J. Zuehlsdorff , Nicholas D. M. Hine , Mike C. Payne , Peter D. Haynes

Nonlinear time fractional partial differential equations are widely used in modeling and simulations. In many applications, there are high contrast changes in media properties. For solving these problems, one often uses coarse spatial grid…

Numerical Analysis · Mathematics 2022-07-13 Wenyuan Li , Anatoly Alikhanov , Yalchin Efendiev , Wing Tat Leung

The long time behavior of the dynamics of a fast-slow system of ordinary differential equations is examined. The system is derived from a spatial discretization of a Korteweg-de Vries-Burgers type equation, with fast dispersion and slow…

Numerical Analysis · Mathematics 2009-08-20 Zvi Artstein , C. William Gear , Ioannis G. Kevrekidis , Marshall Slemrod , Edriss S. Titi

The parameters in the governing system of partial differential equations of multicompartmental poroelastic models typically vary over several orders of magnitude making its stable discretization and efficient solution a challenging task. In…

Numerical Analysis · Mathematics 2018-06-12 Qinggou Hong , Johannes Kraus , Maria Lymbery , Fadi Philo