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In this work, we consider bilevel optimization when the lower-level problem is strongly convex. Recent works show that with a Hessian-vector product (HVP) oracle, one can provably find an $\epsilon$-stationary point within…

Optimization and Control · Mathematics 2026-05-26 Lesi Chen , Yaohua Ma , Jingzhao Zhang

To contrast different generators for flow equations for Hamiltonians and to discuss the dependence of physical quantities on unitarily equivalent, but effectively different initial Hamiltonians, a numerically solvable model is considered…

Statistical Mechanics · Physics 2009-11-07 T. Stauber , A. Mielke

In this article, the local convergence analysis of the multi-step seventh order method is presented for solving nonlinear equations. The point worth noting in our paper is that our analysis requires a weak hypothesis where the Fr\'echet…

Numerical Analysis · Mathematics 2021-12-14 Akanksha Saxena , J. P. Jaiswal , K. R. Pardasani

Control of complex turbulent dynamical systems involving strong nonlinearity and high degrees of internal instability is an important topic in practice. Different from traditional methods for controlling individual trajectories, controlling…

Dynamical Systems · Mathematics 2023-07-31 Jeffrey Covington , Di Qi , Nan Chen

Shallow free surface flows are often characterized by both subdomains that require high modeling complexity and subdomains that can be sufficiently accurately modeled with low modeling complexity. Moreover, these subdomains may change in…

Fluid Dynamics · Physics 2025-11-04 Rik Verbiest , Julian Koellermeier

Many applications of computational fluid dynamics require multiple simulations of a flow under different input conditions. In this paper, a numerical algorithm is developed to efficiently determine a set of such simulations in which the…

Numerical Analysis · Mathematics 2017-05-29 Max Gunzburger , Nan Jiang , Zhu Wang

Motivated by dimension reduction in regression analysis and signal detection, we investigate the order determination for large dimension matrices including spiked models of which the numbers of covariates are proportional to the sample…

Methodology · Statistics 2019-11-01 Yicheng Zeng , Lixing Zhu

We study, by means of a topological approach, the forced oscillations of second order functional retarded differential equations subject to periodic perturbations. We consider a delay-type functional dependence involving a gamma probability…

Classical Analysis and ODEs · Mathematics 2022-05-30 Alessandro Calamai , Maria Patrizia Pera , Marco Spadini

We study nonlocal first-order equations arising in the theory of dislocations. We prove the existence and uniqueness of the solutions of these equations in the case of positive and negative velocities, under suitable regularity assumptions…

Analysis of PDEs · Mathematics 2009-02-13 Guy Barles , Olivier Ley

We study possible advantages of randomized and quantum computing over deterministic computing for scalar initial-value problems for ordinary differential equations of order k. For systems of equations of the first order this question has…

Quantum Physics · Physics 2007-05-23 Marek Szczesny

We develop a hierarchical description of traffic flow control by means of driver-assist vehicles aimed at the mitigation of speed-dependent road risk factors. Microscopic feedback control strategies are designed at the level of…

Physics and Society · Physics 2019-05-13 Andrea Tosin , Mattia Zanella

This paper delves into stochastic optimization problems that involve Markovian noise. We present a unified approach for the theoretical analysis of first-order gradient methods for stochastic optimization and variational inequalities. Our…

Optimization and Control · Mathematics 2024-04-02 Aleksandr Beznosikov , Sergey Samsonov , Marina Sheshukova , Alexander Gasnikov , Alexey Naumov , Eric Moulines

We consider settings for which one needs to perform multiple flow simulations based on the Navier-Stokes equations, each having different values for the physical parameters and/or different initial condition data, boundary conditions data,…

Numerical Analysis · Mathematics 2017-06-14 Max Gunzburger , Nan Jiang , Zhu Wang

We construct families of approximate solutions to the initial value problem and provide complete mathematical proofs that they tend to satisfy the standard system of isothermal one pressure two-fluid flows in 1-D when the data are $L^1$ in…

Analysis of PDEs · Mathematics 2014-06-03 Mathilde Colombeau

A central challenge to using first-order methods for optimizing nonconvex problems is the presence of saddle points. First-order methods often get stuck at saddle points, greatly deteriorating their performance. Typically, to escape from…

Machine Learning · Computer Science 2017-09-06 Sashank J Reddi , Manzil Zaheer , Suvrit Sra , Barnabas Poczos , Francis Bach , Ruslan Salakhutdinov , Alexander J Smola

In this letter, we provide counter-examples to demonstrate that it is possible to retain second-order accuracy using Sakurai et al.'s method, even when different flux boundary conditions are imposed on multiple interfaces that do not…

Numerical Analysis · Mathematics 2021-02-11 Ramakrishnan Thirumalaisamy , Nishant Nangia , Amneet Pal Singh Bhalla

Fast flow models accelerate the iterative sampling process by learning to directly predict ODE path integrals, enabling one-step or few-step generation. However, we argue that current fast-flow training paradigms suffer from two fundamental…

Computer Vision and Pattern Recognition · Computer Science 2026-02-09 Tianyi Zhang , Chengcheng Liu , Jinwei Chen , Chun-Le Guo , Chongyi Li , Ming-Ming Cheng , Bo Li , Peng-Tao Jiang

We focus on the numerical approximation of the Cahn-Hilliard type equations, and present a family of second-order unconditionally energy-stable schemes. By reformulating the equation into an equivalent system employing a scalar auxiliary…

Fluid Dynamics · Physics 2018-03-19 Suchuan Dong , Zhiguo Yang , Lianlei Lin

Turbulence is characterized by the non-linear cascades of energy and other inviscid invariants across a huge range of scales, from where they are injected to where they are dissipated. Recently, new experimental, numerical and theoretical…

Fluid Dynamics · Physics 2018-10-10 A. Alexakis , L. Biferale

The optimization of the mixing of a passive scalar at finite P\'eclet number $Pe=Uh/\kappa$ (where $U,h$ are characteristic velocity and length scales and $\kappa$ is the scalar diffusivity) is relevant to many significant flow challenges…

Fluid Dynamics · Physics 2022-11-23 Conor Heffernan , Colm-cille Caulfield