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The question of fast convergence in the classical problem of high dimensional linear regression has been extensively studied. Arguably, one of the fastest procedures in practice is Iterative Hard Thresholding (IHT). Still, IHT relies…

Statistics Theory · Mathematics 2020-08-28 Mohamed Ndaoud

The Multiscale Hierarchical Decomposition Method (MHDM) was introduced as an iterative method for total variation regularization, with the aim of recovering details at various scales from images corrupted by additive or multiplicative…

Numerical Analysis · Mathematics 2023-09-28 Stefan Kindermann , Elena Resmerita , Tobias Wolf

We present the design and implementation details of a geometric multigrid method on adaptively refined meshes for massively parallel computations. The method uses local smoothing on the refined part of the mesh. Partitioning is achieved by…

Numerical Analysis · Computer Science 2021-08-04 Thomas C. Clevenger , Timo Heister , Guido Kanschat , Martin Kronbichler

Fine-tuning large language models (LLMs) poses significant memory challenges, as the back-propagation process demands extensive resources, especially with growing model sizes. Recent work, MeZO, addresses this issue using a zeroth-order…

Machine Learning · Computer Science 2024-11-19 Huaqin Zhao , Jiaxi Li , Yi Pan , Shizhe Liang , Xiaofeng Yang , Wei Liu , Xiang Li , Fei Dou , Tianming Liu , Jin Lu

In this paper, we present a new method to perform numerical simulations of astrophysical MHD flows using the Adaptive Mesh Refinement framework and Constrained Transport. The algorithm is based on a previous work in which the MUSCL--Hancock…

Astrophysics · Physics 2009-11-11 S. Fromang , P. Hennebelle , R. Teyssier

We define a regularized size-shape distortion (quality) measure for curved high-order elements on a Riemannian space. To this end, we measure the deviation of a given element, straight-sided or curved, from the stretching, alignment, and…

Computational Engineering, Finance, and Science · Computer Science 2024-03-21 Guillermo Aparicio-Estrems , Abel Gargallo-Peiró , Xevi Roca

In this paper, we extend the unsplit staggered mesh scheme (USM) for 2D magnetohydrodynamics (MHD) (Lee and Deane, 2009) to a full 3D MHD scheme. The scheme is a finite-volume Godunov method consisting of a constrained transport (CT) method…

Computational Physics · Physics 2013-03-29 Dongwook Lee

We study in this paper three variants of the high-order Discontinuous Galerkin (DG) method with Runge-Kutta (RK) time integration for the induction equation, analysing their ability to preserve the divergence free constraint of the magnetic…

Numerical Analysis · Mathematics 2021-03-25 Maria Han Veiga , David A Velasco-Romero , Quentin Wenger , Romain Teyssier

In this article we present the first better than second order accurate unstructured Lagrangian-type one-step WENO finite volume scheme for the solution of hyperbolic partial differential equations with non-conservative products. The method…

Numerical Analysis · Mathematics 2013-04-18 Michael Dumbser , Walter Boscheri

This paper presents a fully multidimensional kernel-based reconstruction scheme for finite volume methods applied to systems of hyperbolic conservation laws, with a particular emphasis on the compressible Euler equations. Non-oscillatory…

Numerical Analysis · Mathematics 2024-01-31 Ian May , Dongwook Lee

Computational magnetohydrodynamics (MHD) for space physics has become an essential area in understanding the multiscale dynamics of geophysical and astrophysical plasma processes, partially motivated by the lack of space data. Full MHD…

In massive multiple-input multiple-output (MIMO) systems, hybrid analog-digital (AD) beamforming can be used to attain a high directional gain without requiring a dedicated radio frequency (RF) chain for each antenna element, which…

Signal Processing · Electrical Eng. & Systems 2021-09-15 S. Shi , Y. Cai , Q. Hu , B. Champagne , L. Hanzo

In this article we present a new family of high order accurate Arbitrary Lagrangian-Eulerian one-step WENO finite volume schemes for the solution of stiff hyperbolic balance laws. High order accuracy in space is obtained with a standard…

Numerical Analysis · Mathematics 2014-11-24 Michael Dumbser , Ariunaa Uuriintsetseg , Olindo Zanotti

High-order Godunov methods for gas dynamics have become a standard tool for simulating different classes of astrophysical flows. Their accuracy is mostly determined by the spatial interpolant used to reconstruct the pair of Riemann states…

Solar and Stellar Astrophysics · Physics 2024-05-29 G. Leidi , R. Andrassy , W. Barsukow , J. Higl , P. V. F. Edelmann , F. K. Röpke

We present a detailed analysis of a new, iterative density reconstruction algorithm. This algorithm uses a decreasing smoothing scale to better reconstruct the density field in Lagrangian space. We implement this algorithm to run on the…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-19 Xinyi Chen , Nikhil Padmanabhan

Many areas of science and engineering encounter data defined on spherical manifolds. Modelling and analysis of spherical data often necessitates spherical harmonic transforms, at high degrees, and increasingly requires efficient computation…

Computational Physics · Physics 2025-06-19 Matthew A. Price , Jason D. McEwen

This work investigates a novel approach for the high order evolution of hyperbolic PDEs using ADER discontinuous Galerkin schemes within a direct Arbitrary-Lagrangian-Eulerian (ALE) framework on 3D moving polyhedral meshes with topology…

Numerical Analysis · Mathematics 2026-05-25 Elena Gaburro , Matej Klima , Mauro Bonafini , Maurizio Tavelli

This contribution investigates the connection between isogeometric analysis and integral equation methods for full-wave electromagnetic problems up to the low-frequency limit. The proposed spline-based integral equation method allows for an…

Computational Engineering, Finance, and Science · Computer Science 2026-05-19 Maximilian Nolte , Riccardo Torchio , Sebastian Schöps , Jürgen Dölz , Felix Wolf , Albert E. Ruehli

We present a simple yet effective method for skeleton-free motion retargeting. Previous methods transfer motion between high-resolution meshes, failing to preserve the inherent local-part motions in the mesh. Addressing this issue, our…

Computer Vision and Pattern Recognition · Computer Science 2023-03-21 Haoyu Wang , Shaoli Huang , Fang Zhao , Chun Yuan , Ying Shan

We propose an inexact optimization algorithm on Riemannian manifolds, motivated by quadratic discrimination tasks in high-dimensional, low-sample-size (HDLSS) imaging settings. In such applications, gradient evaluations are often biased due…

Optimization and Control · Mathematics 2025-07-08 Uday Talwar , Meredith K. Kupinski , Afrooz Jalilzadeh