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Multiphysics problems such as multicomponent diffusion, phase transformations in multiphase systems and alloy solidification involve numerical solution of a coupled system of nonlinear partial differential equations (PDEs). Numerical…

材料科学 · 物理学 2022-11-24 Vir Karan , A. Maruthi Indresh , Saswata Bhattacharyya

We propose a gradient-based method for quadratic programming problems with a single linear constraint and bounds on the variables. Inspired by the GPCG algorithm for bound-constrained convex quadratic programming [J.J. Mor\'e and G.…

最优化与控制 · 数学 2019-02-19 Daniela di Serafino , Gerardo Toraldo , Marco Viola , Jesse Barlow

Local Fourier analysis is a useful tool for predicting and analyzing the performance of many efficient algorithms for the solution of discretized PDEs, such as multigrid and domain decomposition methods. The crucial aspect of local Fourier…

最优化与控制 · 数学 2020-07-29 Jed Brown , Yunhui He , Scott MacLachlan , Matt Menickelly , Stefan M. Wild

In this work, we extend the meshfree generalized multiscale exponential integration framework introduced in Nikiforov et al. (2025) to the simulation of three-dimensional advection--diffusion problems in heterogeneous and high-contrast…

Decentralized optimization algorithms have recently attracted increasing attention due to its wide applications in all areas of science and engineering. In these algorithms, a collection of agents collaborate to minimize the average of a…

最优化与控制 · 数学 2024-09-18 Shujing Feng , Xin Jiang

Long simulation times in climate sciences typically require coarse grids due to computational constraints. Nonetheless, unresolved subscale information significantly influences the prognostic variables and can not be neglected for reliable…

数值分析 · 数学 2018-02-22 Konrad Simon , Jörn Behrens

Time-parallel algorithms, such as Parareal, are well-understood for linear problems, but their convergence analysis for nonlinear, chaotic systems remains limited. This paper introduces a new theoretical framework for analysing…

Algebraic multigrid (AMG) is often an effective solver for symmetric positive definite (SPD) linear systems resulting from the discretization of general elliptic PDEs, or the spatial discretization of parabolic PDEs. However, convergence…

数值分析 · 数学 2019-09-10 Thomas A. Manteuffel , Steffen Munzenmaier , John Ruge , Ben S. Southworth

For time-dependent problems with high-contrast multiscale coefficients, the time step size for explicit methods is affected by the magnitude of the coefficient parameter. With a suitable construction of multiscale space, one can achieve a…

数值分析 · 数学 2022-04-01 Wing Tat Leung , Yating Wang

Finite element discretization of time dependent problems also require effective time-stepping schemes. While implicit Runge-Kutta methods provide favorable accuracy and stability problems, they give rise to large and complicated systems of…

数值分析 · 数学 2023-05-01 Robert C. Kirby

We analyze families of primal high-order hybridizable discontinuous Galerkin (HDG) methods for solving degenerate (second-order) elliptic problems. One major trouble regarding this class of PDEs concerns its mathematical nature, which may…

数值分析 · 数学 2021-06-02 G. Etangsale , M. Fahs , V. Fontaine , A. R. Isa-Abadi

This paper describes a massively parallel algebraic multigrid method based on non-smoothed aggregation. It is especially suited for solving heterogeneous elliptic problems as it uses a greedy heuristic algorithm for the aggregation that…

数值分析 · 数学 2013-10-01 Markus Blatt , Olaf Ippisch , Peter Bastian

Stochastic Gradient Langevin Dynamics (SGLD) ensures strong guarantees with regards to convergence in measure for sampling log-concave posterior distributions by adding noise to stochastic gradient iterates. Given the size of many practical…

机器学习 · 计算机科学 2020-06-15 Vyacheslav Kungurtsev , Bapi Chatterjee , Dan Alistarh

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,…

数值分析 · 数学 2021-01-25 Andrea Barth , Andreas Stein

We present a robust and efficient target-based mesh adaptation methodology, building on hybridized discontinuous Galerkin schemes for (nonlinear) convection-diffusion problems, including the compressible Euler and Navier-Stokes equations.…

数值分析 · 数学 2014-11-12 Michael Woopen , Georg May , Jochen Schütz

Many astrophysical simulations involve extreme dynamic range of timescales around 'special points' in the domain (e.g. black holes, stars, planets, disks, galaxies, shocks, mixing interfaces), where processes on small scales couple strongly…

天体物理仪器与方法 · 物理学 2026-05-11 Philip F. Hopkins , Elias R. Most

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…

计算物理 · 物理学 2020-06-24 Niklas Fehn , Peter Munch , Wolfgang A. Wall , Martin Kronbichler

Fault tolerant algorithms for the numerical approximation of elliptic partial differential equations on modern supercomputers play a more and more important role in the future design of exa-scale enabled iterative solvers. Here, we combine…

数学软件 · 计算机科学 2015-06-23 Markus Huber , Björn Gmeiner , Ulrich Rüde , Barbara Wohlmuth

The study on the implicit regularization induced by gradient-based optimization is a longstanding pursuit. In the present paper, we characterize the implicit regularization of momentum gradient descent (MGD) with early stopping by comparing…

机器学习 · 计算机科学 2022-01-17 Li Wang , Yingcong Zhou , Zhiguo Fu

The rigorous solution to the grating diffraction problem is a cornerstone step in many scientific fields and industrial applications ranging from the study of the fundamental properties of metasurfaces to the simulation of photolithography…

计算物理 · 物理学 2025-02-05 Evgeniy Levdik , Alexey A. Shcherbakov