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We present a finite element discretization of a non-linear diffusion equation used in the field of critical phenomena and, more recently, in the context of Dynamic Density Functional Theory. The discretized equation preserves the structure…

Statistical Mechanics · Physics 2015-06-23 J. A. de la Torre , Pep Español , Aleksandar Donev

We propose nonlinear semi-discrete and discrete models for the elastic energy induced by a finite systems of edge dislocations in two dimensions. Within the dilute regime, we analyze the asymptotic behavior of the nonlinear elastic energy,…

Analysis of PDEs · Mathematics 2023-05-04 Roberto Alicandro , Lucia De Luca , Mariapia Palombaro , Marcello Ponsiglione

A multigrid framework is described for multiphysics applications. The framework allows one to construct, adapt, and tailor a monolithic multigrid methodology to different linear systems coming from discretized partial differential…

Numerical Analysis · Mathematics 2021-03-24 Peter Ohm , Tobias Wiesner , Eric C. Cyr , Jonathan J. Hu , John N. Shadid , Raymond S. Tuminaro

In this paper we consider a wide class of discrete diffusion load balancing algorithms. The problem is defined as follows. We are given an interconnection network and a number of load items, which are arbitrarily distributed among the nodes…

Distributed, Parallel, and Cluster Computing · Computer Science 2014-12-23 Hoda Akbari , Petra Berenbrink , Robert Elsässer , Dominik Kaaser

In this paper we present a Local Fourier Analysis of a space-time multigrid solver for a hyperbolic test problem. The space-time discretization is based on arbitrarily high order discontinuous Galerkin spectral element methods in time and a…

Numerical Analysis · Mathematics 2021-12-07 Lea M. Versbach , Philipp Birken , Viktor Linders , Gregor Gassner

We apply geometric multigrid methods for the finite element approximation of flow problems governed by Darcy and Brinkman systems used in modeling highly heterogeneous porous media. The method is based on divergence-conforming discontinuous…

Numerical Analysis · Mathematics 2021-02-02 Guido Kanschat , Raytcho Lazarov , Youli Mao

Developments in dynamical systems theory provides new support for the discretisation of \pde{}s and other microscale systems. By systematically resolving subgrid microscale dynamics the new approach constructs asymptotically accurate,…

Numerical Analysis · Mathematics 2009-04-07 Tony MacKenzie , A. J. Roberts

Space and time scales are not independent in diffusion. In fact, numerical simulations show that different patterns are obtained when space and time steps ($\Delta x$ and $\Delta t$) are varied independently. On the other hand, anisotropy…

patt-sol · Physics 2015-06-26 Rui Dilao , Joaquim Sainhas

By the use of Green's second integral identity we determine the field scattered from a two-dimensional randomly rough isotropic or anisotropic Dirichlet or Neumann surface when it is illuminated by a scalar Gaussian beam. The integral…

Subsurface flows are commonly modeled by advection-diffusion equations. Insufficient measurements or uncertain material procurement may be accounted for by random coefficients. To represent, for example, transitions in heterogeneous media,…

Numerical Analysis · Mathematics 2021-01-25 Andrea Barth , Andreas Stein

The efficient solution of sparse, linear systems resulting from the discretization of partial differential equations is crucial to the performance of many physics-based simulations. The algorithmic optimality of multilevel approaches for…

Mathematical Software · Computer Science 2018-03-08 Andrew Reisner , Luke N. Olson , J. David Moulton

We consider variational problems that model the bending behavior of curves that are constrained to belong to given hypersurfaces. Finite element discretizations of corresponding functionals are justified rigorously via Gamma-convergence.…

Numerical Analysis · Mathematics 2020-04-24 Sören Bartels

The present work develops hybrid multigrid methods for high-order discontinuous Galerkin discretizations of elliptic problems. Fast matrix-free operator evaluation on tensor product elements is used to devise a computationally efficient PDE…

Computational Physics · Physics 2020-06-24 Niklas Fehn , Peter Munch , Wolfgang A. Wall , Martin Kronbichler

Heterogeneous anisotropic diffusion problems arise in the various areas of science and engineering including plasma physics, petroleum engineering, and image processing. Standard numerical methods can produce spurious oscillations when they…

Numerical Analysis · Mathematics 2015-05-18 Xianping Li , Weizhang Huang

In this paper, we study the equilibria of an anisotropic, nonlocal aggregation equation with nonlinear diffusion which does not possess a gradient flow structure. Here, the anisotropy is induced by an underlying tensor field. Anisotropic…

Analysis of PDEs · Mathematics 2021-04-08 José A. Carrillo , Bertram Düring , Lisa Maria Kreusser , Carola-Bibiane Schönlieb

This paper addresses the topological structure of steady, anisotropic, inhomogeneous diffusion problems. Two discrete formulations: a) mixed and b) direct formulations are discussed. Differential operators are represented by sparse…

Numerical Analysis · Mathematics 2018-02-14 Marc Gerritsma , Artur Palha , Varun Jain , Yi Zhang

Coherency misfit stresses and their related anisotropies are known to influence the equilibrium shapes of precipitates. Additionally, mechanical properties of the alloys are also dependent on the shapes of the precipitates. Therefore, in…

Materials Science · Physics 2018-08-29 Bhalchandra Bhadak , R. Sankarasubramanian , Abhik Choudhury

In this paper, we develop multigrid solvers for the biharmonic problem in the framework of isogeometric analysis (IgA). In this framework, one typically sets up B-splines on the unit square or cube and transforms them to the domain of…

Numerical Analysis · Mathematics 2019-06-18 Jarle Sogn , Stefan Takacs

Effective Hamiltonians can explain in a much simpler way the physics behind a scattering process. Chaotic scattering is directly related to Lorentzian Hamiltonians which, because of their properties, can be reduced to a $2\times 2$ matrix…

Disordered Systems and Neural Networks · Physics 2013-04-03 Adel Abbout , Peng Mei

$L^1$ based optimization is widely used in image denoising, machine learning and related applications. One of the main features of such approach is that it naturally provide a sparse structure in the numerical solutions. In this paper, we…

Numerical Analysis · Mathematics 2023-02-13 Weifeng Qiu , Jin Ren , Ke Shi , Yuesheng Xu