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We study nonlinearly preconditioned gradient methods for smooth nonconvex optimization problems, focusing on sigmoid preconditioners that inherently perform a form of gradient clipping akin to the widely used gradient clipping technique.…

Optimization and Control · Mathematics 2025-10-14 Konstantinos Oikonomidis , Jan Quan , Panagiotis Patrinos

We are concerned with the suitability of the main models of compressible fluid dynamics for the Lighthill problem for shock diffraction by a convex corned wedge, by studying the regularity of solutions of the problem, which can be…

Analysis of PDEs · Mathematics 2020-03-12 Gui-Qiang Chen , Mikhail Feldman , Jingchen Hu , Wei Xiang

The numerical sign problem remains one of the central challenges in computational physics. The Worldvolume Hybrid Monte Carlo (WV-HMC) method has recently been proposed as a reliable and computationally efficient algorithm that crucially…

High Energy Physics - Lattice · Physics 2026-03-31 Masafumi Fukuma

We present a new way to construct analytical solutions for flow in complex microfluidic channel networks, as well as planar disordered media. Using a combination of Schwarz-Christoffel maps and segmentation techniques inspired by integrated…

Fluid Dynamics · Physics 2026-03-24 Etienne Boulais , Richard D. Braatz

We present a macro-scale description of quasi-periodically developed flow in channels, which relies on double volume-averaging. We show that quasi-developed macro-scale flow is characterized by velocity modes which decay exponentially in…

Fluid Dynamics · Physics 2022-02-17 Geert Buckinx

The iterative diagonalization of a sequence of large ill-conditioned generalized eigenvalue problems is a computational bottleneck in quantum mechanical methods employing a nonorthogonal basis for {\em ab initio} electronic structure…

Materials Science · Physics 2013-08-13 Yunfeng Cai , Zhaojun Bai , John E. Pask , N. Sukumar

In this paper, we suggest a new framework for analyzing primal subgradient methods for nonsmooth convex optimization problems. We show that the classical step-size rules, based on normalization of subgradient, or on the knowledge of optimal…

Optimization and Control · Mathematics 2023-11-27 Yurii Nesterov

We consider the Dirichlet problem for a compressible two-fluid model in three dimensions, and obtain the global existence of weak solution with large initial data and independent adiabatic constants \Gamma,\gamma>=9/5. The pressure…

Analysis of PDEs · Mathematics 2021-07-27 Huanyao Wen

Preconditioning is at the core of modern many-fermion Monte Carlo algorithms, such as Hybrid Monte Carlo, where the repeated solution of a linear problem involving an ill-conditioned matrix is needed. We report on a performance comparison…

High Energy Physics - Lattice · Physics 2010-08-24 Timour Ten , Joaquín E. Drut , Timo A. Lähde

We consider stochastic differential equations driven by Wiener processes. The vector fields are supposed to satisfy only local Lipschitz conditions. The Lipschitz constants of the drift vector field, valid on balls of radius $R$, are…

Probability · Mathematics 2007-05-23 Shizan Fang , Peter Imkeller , Tusheng Zhang

In this paper, we study the problem of shock reflection by a wedge, with the potential flow equation, which is a simplification of the Euler System. In the work of M. Feldman and G. Chen, the existence theory of shock reflection problems…

Analysis of PDEs · Mathematics 2021-03-31 Jingchen Hu

We show that the standard discrete update rule of transformer layers can be naturally interpreted as a forward Euler discretization of a continuous dynamical system. Our Transformer Flow Approximation Theorem demonstrates that, under…

Machine Learning · Computer Science 2025-05-26 Jacob Fein-Ashley

In this paper, we revisit the large-scale constrained linear regression problem and propose faster methods based on some recent developments in sketching and optimization. Our algorithms combine (accelerated) mini-batch SGD with a new…

Machine Learning · Computer Science 2018-02-12 Di Wang , Jinhui Xu

The aim of this article is to study the limiting behavior of the solutions for the scaled generalized Euler equations of compressible fluid flow. When the initial data is of Riemann type, we showed the existence of solution which consists…

Analysis of PDEs · Mathematics 2019-07-17 Manas Ranjan Sahoo , Abhrojyoti Sen

This paper is focused on the generalized Forchheimer flows of slightly compressible fluids in porous media. They are reformulated as a degenerate parabolic equation for the pressure. The initial boundary value problem is studied with…

Analysis of PDEs · Mathematics 2015-10-02 Luan Hoang , Thinh Kieu

This work studies a variational formulation and numerical solution of a regularized morphoelasticity problem of shape evolution. The foundation of our analysis is based on the governing equations of linear elasticity, extended to account…

Numerical Analysis · Mathematics 2026-05-13 Ziqin Zhou

We introduce a geometric evolution equation of hyperbolic type, which governs the evolution of a hypersurface moving in the direction of its mean curvature vector. The flow stems from a geometrically natural action containing kinetic and…

Differential Geometry · Mathematics 2007-12-04 Philippe G. LeFloch , Knut Smoczyk

Hele-Shaw problems are prototypes to study the interface dynamics. Linear theory suggests the existence of self-similar patterns in a Hele-Shaw flow. That is, with a specific injection flux the interface shape remains unchanged while its…

Analysis of PDEs · Mathematics 2024-01-05 Wang Xiao , Lingyu Feng , Kai Liu , Meng Zhao

Despite the widespread success of Transformers across various domains, their optimization guarantees in large-scale model settings are not well-understood. This paper rigorously analyzes the convergence properties of gradient flow in…

Machine Learning · Statistics 2024-11-01 Cheng Gao , Yuan Cao , Zihao Li , Yihan He , Mengdi Wang , Han Liu , Jason Matthew Klusowski , Jianqing Fan

During industrial processing, unforeseen defects may arise in products due to uncontrollable factors. Although unsupervised methods have been successful in defect localization, the usual use of pre-trained models results in low-resolution…

Computer Vision and Pattern Recognition · Computer Science 2023-03-07 Jiarui Lei , Xiaobo Hu , Yue Wang , Dong Liu