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Convergence acceleration of flow simulations to their steady states at lower Mach numbers can be achieved via preconditioning the lattice Boltzmann (LB) schemes that alleviate the associated numerical stiffness, which have so far been…

Computational Physics · Physics 2022-08-17 Eman Yahia , Kannan Premnath

We survey a number of moment hierarchies and test their performances in computing one-dimensional shock structures. It is found that for high Mach numbers, the moment hierarchies are either computationally expensive or hard to converge,…

Fluid Dynamics · Physics 2021-08-25 Zhenning Cai

Direct simulation of physical processes on a kinetic level is prohibitively expensive in aerospace applications due to the extremely high dimension of the solution spaces. In this paper, we consider the moment system of the Boltzmann…

Numerical Analysis · Mathematics 2021-06-18 Steffen Schotthöfer , Tianbai Xiao , Martin Frank , Cory D. Hauck

This work focuses on developing and motivating a stochastic version of a wellknown inverse problem methodology. Specifically, we consider the iteratively regularized Gauss-Newton method, originally proposed by Bakushinskii for…

Numerical Analysis · Mathematics 2024-09-20 El Houcine Bergou , Neil K. Chada , Youssef Diouane

A second order accurate, linear numerical method is analyzed for the Landau-Lifshitz equation with large damping parameters. This equation describes the dynamics of magnetization, with a non-convexity constraint of unit length of the…

Numerical Analysis · Mathematics 2021-11-16 Yongyong Cai , Jingrun Chen , Cheng Wang , Changjian Xie

Irregular time series data are prevalent in the real world and are challenging to model with a simple recurrent neural network (RNN). Hence, a model that combines the use of ordinary differential equations (ODE) and RNN was proposed…

Machine Learning · Computer Science 2022-07-13 Ting Fung Lam , Yony Bresler , Ahmed Khorshid , Nathan Perlmutter

We present a convex approach to probabilistic segmentation and modeling of time series data. Our approach builds upon recent advances in multivariate total variation regularization, and seeks to learn a separate set of parameters for the…

Machine Learning · Statistics 2015-11-17 Matt Wytock , J. Zico Kolter

Recently algorithms incorporating second order curvature information have become popular in training neural networks. The Nesterov's Accelerated Quasi-Newton (NAQ) method has shown to effectively accelerate the BFGS quasi-Newton method by…

Machine Learning · Computer Science 2020-10-16 Sota Yasuda , Shahrzad Mahboubi , S. Indrapriyadarsini , Hiroshi Ninomiya , Hideki Asai

We analyze Newton's method with lazy Hessian updates for solving general possibly non-convex optimization problems. We propose to reuse a previously seen Hessian for several iterations while computing new gradients at each step of the…

Optimization and Control · Mathematics 2023-06-16 Nikita Doikov , El Mahdi Chayti , Martin Jaggi

In this paper we present a new ultra efficient numerical method for solving kinetic equations. In this preliminary work, we present the scheme in the case of the BGK relaxation operator. The scheme, being based on a splitting technique…

Mathematical Physics · Physics 2015-06-04 Giacomo Dimarco , Raphaël Loubere

A greedy randomized nonlinear Bregman-Kaczmarz method by sampling the working index with residual information is developed for the solution of the constrained nonlinear system of equations. Theoretical analyses prove the convergence of the…

Numerical Analysis · Mathematics 2024-06-25 Aqin Xiao , Junfeng Yin

The numerical approximation of an inverse problem subject to the convection--diffusion equation when diffusion dominates is studied. We derive Carleman estimates that are on a form suitable for use in numerical analysis and with explicit…

Numerical Analysis · Mathematics 2020-06-25 Erik Burman , Mihai Nechita , Lauri Oksanen

We consider the numerical approximation of a generalized fractional Oldroyd-B fluid problem involving two Riemann-Liouville fractional derivatives in time. We establish regularity results for the exact solution which play an important role…

Numerical Analysis · Mathematics 2018-11-06 Mariam Al-Maskari , Samir Karaa

In this paper, we study numerical methods for the homogenization of linear second-order elliptic equations in nondivergence-form with periodic diffusion coefficients and large drift terms. Upon noting that the effective diffusion matrix can…

Numerical Analysis · Mathematics 2025-06-18 Timo Sprekeler , Han Wu , Zhiwen Zhang

This paper proposes a novel stochastic version of damped and regularized BFGS method for addressing the above problems.

Numerical Analysis · Mathematics 2019-12-11 H. Chen , H. C. Wu , S. C. Chan , W. H. Lam

We propose a class of numerical methods for the nonlinear Schr\"odinger (NLS) equation that conserves mass and energy, is of arbitrarily high-order accuracy in space and time, and requires only the solution of a scalar algebraic equation…

Numerical Analysis · Mathematics 2025-10-17 Hendrik Ranocha , David I. Ketcheson

The nonlinear Schr\"{o}dinger (NLS) equation possesses an infinite hierarchy of conserved densities and the numerical preservation of some of these quantities is critical for accurate long-time simulations, particularly for multi-soliton…

Numerical Analysis · Mathematics 2023-09-06 Abhijit Biswas , David I. Ketcheson

Robust estimation is essential in computer vision, robotics, and navigation, aiming to minimize the impact of outlier measurements for improved accuracy. We present a fast algorithm for Geman-McClure robust estimation, FracGM, leveraging…

Computer Vision and Pattern Recognition · Computer Science 2024-11-22 Bang-Shien Chen , Yu-Kai Lin , Jian-Yu Chen , Chih-Wei Huang , Jann-Long Chern , Ching-Cherng Sun

In this paper, we propose a first second-order scheme based on arbitrary non-Euclidean norms, incorporated by Bregman distances. They are introduced directly in the Newton iterate with regularization parameter proportional to the square…

Optimization and Control · Mathematics 2021-12-07 Nikita Doikov , Yurii Nesterov

This paper considers the regularization continuation method and the trust-region updating strategy for the optimization problem with linear equality constraints.The proposed method utilizes the linear conservation law of the regularization…

Numerical Analysis · Mathematics 2022-04-11 Xin-long Luo , Hang Xiao