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In this work, we provide a global condition for contraction with respect to an invariant Riemannian metric on reductive homogeneous spaces. Using left-invariant frames, vector fields on the manifold are horizontally lifted to the ambient…

Systems and Control · Electrical Eng. & Systems 2025-07-01 Akash Harapanahalli , Samuel Coogan

This paper investigates model-order reduction methods for geometrically nonlinear structures. The parametrisation method of invariant manifolds is used and adapted to the case of mechanical systems expressed in the physical basis, so that…

Numerical Analysis · Mathematics 2021-09-22 Alessandra Vizzaccaro , Andrea Opreni , Loïc Salles , Attilio Frangi , Cyril Touzé

Integrated sensing and communication (ISAC) has been widely recognized as one of the key technologies for 6G wireless networks. In this paper, we focus on the waveform design of ISAC system, which can realize radar sensing while also…

Signal Processing · Electrical Eng. & Systems 2025-04-09 Jiangtao Wang , Xuyang Zhao , Muyu Mei , Yongchao Wang

Algebraic multigrid (AMG) methods are powerful solvers with linear or near-linear computational complexity for certain classes of linear systems, Ax=b. Broadening the scope of problems that AMG can effectively solve requires the development…

Numerical Analysis · Mathematics 2019-02-15 James Brannick , Scott P. MacLachlan , Jacob B. Schroder , Ben S. Southworth

The strictly gauge invariant approach to the construction of the analog of guiding center integrals of motion in spatially homogeneous/inhomogeneous constant magnetic fields is considered. With their help the gauge invariant equations,…

Mesoscale and Nanoscale Physics · Physics 2023-01-30 E. L. Rumyantsev , A. V. Germanenko

Recently, a Riemannian proximal Newton method has been developed for optimizing problems in the form of $\min_{x\in\mathcal{M}} f(x) + \mu \|x\|_1$, where $\mathcal{M}$ is a compact embedded submanifold and $f(x)$ is smooth. Although this…

Optimization and Control · Mathematics 2025-03-25 Wen Huang , Wutao Si

A general real-space multigrid algorithm MIKA (Multigrid Instead of the K-spAce) for the self-consistent solution of the Kohn-Sham equations appearing in the state-of-the-art electronic-structure calculations is described. The most…

Condensed Matter · Physics 2007-05-23 T. Torsti , M. Heiskanen , M. J. Puska , R. M. Nieminen

We introduce a novel Unsmoothed Aggregation (UA) Algebraic Multigrid (AMG) method combined with Preconditioned Conjugate Gradient (PCG) to overcome the limitations of Extended Position-Based Dynamics (XPBD) in high-resolution and…

Graphics · Computer Science 2025-05-20 Chunlei Li , Peng Yu , Tiantian Liu , Siyuan Yu , Yuting Xiao , Shuai Li , Aimin Hao , Yang Gao , Qinping Zhao

In this paper, we design unimodular waveforms with good correlation properties for multi-input multi-output (MIMO) radar systems. Specifically, first, we analyze the geometric properties of the unimodular constraint in the fourth-order…

Signal Processing · Electrical Eng. & Systems 2025-04-09 Xuyang Zhao , Jiangtao Wang , Shihao Yan , Yongchao Wang

In this paper, we introduce an inertial version of the Proximal Incremental Aggregated Gradient method (PIAG) for minimizing the sum of smooth convex component functions and a possibly nonsmooth convex regularization function.…

Optimization and Control · Mathematics 2017-12-19 Xiaoya Zhang , Wei Peng , Hui Zhang , Wei Zhu

Let $M$ be a finite volume analytic pseudo-Riemannian manifold that admits an isometric $G$-action with a dense orbit, where $G$ is a connected non-compact simple Lie group. For low-dimensional $M$, i.e. $\dim(M) < 2\dim(G)$, when the…

Differential Geometry · Mathematics 2020-01-07 Raul Quiroga-Barranco

We present a pedagogical discussion of Similarity Renormalization Group (SRG) methods, in particular the In-Medium SRG (IMSRG) approach for solving the nuclear many-body problem. These methods use continuous unitary transformations to…

Nuclear Theory · Physics 2017-06-28 H. Hergert , S. K. Bogner , J. G. Lietz , T. D. Morris , S. J. Novario , N. M. Parzuchowski , F. Yuan

The interfacial diffusion associated with finite volume method (FVM) discretizations of multiphase flows creates the need for an interface sharpening mechanism. Such solutions for structured quadrilateral grids are well documented, but…

Fluid Dynamics · Physics 2026-03-05 J. Marziale , J. Sun , D. Salac , J. Chen

Simulation of multiphase poromechanics involves solving a multi-physics problem in which multiphase flow and transport are tightly coupled with the porous medium deformation. To capture this dynamic interplay, fully implicit methods, also…

Numerical Analysis · Mathematics 2021-01-08 Quan M. Bui , Daniel Osei-Kuffuor , Nicola Castelletto , Joshua A. White

Model reduction is a key technology for large-scale physical systems in science and engineering, as it brings behavior expressed in many degrees of freedom to a more manageable size that subsequently allows control, optimization, and…

Fluid Dynamics · Physics 2024-12-31 R. Ayoub , M. Oulghelou , P. J Schmid

Multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems rely on digital or hybrid digital and analog designs for beamforming against frequency-selective fading, which suffer from high hardware…

Signal Processing · Electrical Eng. & Systems 2026-01-26 Zheao Li , Jiancheng An , Chau Yuen

A recently developed spectral-element adaptive refinement incompressible magnetohydrodynamic (MHD) code [Rosenberg, Fournier, Fischer, Pouquet, J. Comp. Phys. 215, 59-80 (2006)] is applied to simulate the problem of MHD island coalescence…

Computational Physics · Physics 2011-08-31 C. S. Ng , D. Rosenberg , K. Germaschewski , A. Pouquet , A. Bhattacharjee

Modified group projector technique for induced representations is a powerful tool for calculation and symmetry quantum numbers assignation of a tight binding Hamiltonian energy bands of crystals. Namely, the induced type structure of such a…

Soft Condensed Matter · Physics 2009-10-31 M. Damnjanovic , T. Vukovic , I. Milosevic

Algebraic multigrid (AMG) is known to be an effective solver for many sparse symmetric positive definite (SPD) linear systems. For SPD systems, the convergence theory of AMG is well-understood in terms of the $A$-norm, but in a nonsymmetric…

Numerical Analysis · Mathematics 2025-01-14 Ahsan Ali , James Brannick , Karsten Kahl , Oliver A. Krzysik , Jacob B. Schroder , Ben S. Southworth

This paper presents a spatial two-grid (STG) compact difference scheme for a two-dimensional (2D) nonlinear diffusion-wave equation with variable exponent, which describes, e.g., the propagation of mechanical diffusive waves in viscoelastic…

Numerical Analysis · Mathematics 2025-10-15 Hao Zhang , Kexin Li , Wenlin Qiu