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As the size of models and datasets grows, it has become increasingly common to train models in parallel. However, existing distributed stochastic gradient descent (SGD) algorithms suffer from insufficient utilization of computational…

Machine Learning · Computer Science 2023-08-30 Xin Zhou , Ling Chen , Houming Wu

We investigate the problem of finding second-order stationary points (SOSP) in differentially private (DP) stochastic non-convex optimization. Existing methods suffer from two key limitations: (i) inaccurate convergence error rate due to…

Machine Learning · Computer Science 2026-01-21 Youming Tao , Zuyuan Zhang , Dongxiao Yu , Xiuzhen Cheng , Falko Dressler , Di Wang

Staggered grid finite difference scheme is widely used for the first order elastic wave equation, which constitutes the basis for least-squares reverse time migration and full waveform inversion. It is of great importance to improve the…

Geophysics · Physics 2017-06-08 Wenquan Liang , Chaofan Wu , Yanfei Wang , Changchun Yang , Xiaobi Xie

Existing multi-scale solutions lead to a risk of just increasing the receptive field sizes while neglecting small receptive fields. Thus, it is a challenging problem to effectively construct adaptive neural networks for recognizing various…

Computer Vision and Pattern Recognition · Computer Science 2022-09-22 Qingbei Guo , Xiao-Jun Wu , Zhiquan Feng , Tianyang Xu , Cong Hu

Local feature matching aims at finding correspondences between a pair of images. Although current detector-free methods leverage Transformer architecture to obtain an impressive performance, few works consider maintaining local consistency.…

Computer Vision and Pattern Recognition · Computer Science 2023-03-30 Jiahuan Yu , Jiahao Chang , Jianfeng He , Tianzhu Zhang , Feng Wu

We consider the setting where a master wants to run a distributed stochastic gradient descent (SGD) algorithm on $n$ workers, each having a subset of the data. Distributed SGD may suffer from the effect of stragglers, i.e., slow or…

Machine Learning · Computer Science 2022-08-08 Serge Kas Hanna , Rawad Bitar , Parimal Parag , Venkat Dasari , Salim El Rouayheb

We study convergence rates of AdaGrad-Norm as an exemplar of adaptive stochastic gradient methods (SGD), where the step sizes change based on observed stochastic gradients, for minimizing non-convex, smooth objectives. Despite their…

Adaptive mesh refinement (AMR) reduces computational costs in CFD by concentrating resolution where needed, but efficiently embedding complex, non-aligned geometries on GPUs remains challenging. We present a GPU-native algorithm for…

Computational Engineering, Finance, and Science · Computer Science 2026-04-28 Khodr Jaber , Ebenezer E. Essel , Pierre E. Sullivan

Adaptive lattice Boltzmann methods (LBMs) are based on velocity discretizations that self-adjust to local macroscopic conditions such as velocity and temperature. While this feature improves the accuracy and the stability of LBMs for large…

Computational Physics · Physics 2020-11-04 C. Coreixas , J. Latt

We propose a sparse grids based adaptive noise reduction strategy for electrostatic particle-in-cell (PIC) simulations. Our approach is based on the key idea of relying on sparse grids instead of a regular grid in order to increase the…

Various classes of stable finite difference schemes can be constructed to obtain a numerical solution. It is important to select among all stable schemes such a scheme that is optimal in terms of certain additional criteria. In this study,…

Numerical Analysis · Computer Science 2010-06-01 Petr N. Vabishchevich

We study graph clustering in the Stochastic Block Model (SBM) in the presence of both large clusters and small, unrecoverable clusters. Previous convex relaxation approaches achieving exact recovery do not allow any small clusters of size…

Machine Learning · Computer Science 2025-02-25 Matthew Zurek , Yudong Chen

This paper considers a distributed stochastic non-convex optimization problem, where the nodes in a network cooperatively minimize a sum of $L$-smooth local cost functions with sparse gradients. By adaptively adjusting the stepsizes…

Optimization and Control · Mathematics 2024-04-01 Dongyu Han , Kun Liu , Yeming Lin , Yuanqing Xia

We present an extension of the summation-by-parts (SBP) framework to tensor-product spectral-element operators in collapsed coordinates. The proposed approach enables the construction of provably stable discretizations of arbitrary order…

Numerical Analysis · Mathematics 2025-04-29 Tristan Montoya , David W. Zingg

The use of adaptive mesh refinement (AMR) techniques is crucial for accurate and efficient simulation of higher dimensional spacetimes. In this work we develop an adaptive algorithm tailored to the integration of finite difference…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Frans Pretorius , Luis Lehner

We describe a short, reproducible workflow for applying finite differences on nonuniform grids determined by a positive weight function g. The grid is obtained by equidistribution, mapping uniform computational coordinates $\xi\in[0,1]$ to…

Numerical Analysis · Mathematics 2025-08-06 Mário B. Amaro

Semidefinite programs (SDPs) can be solved in polynomial time by interior point methods. However, when the dimension of the problem gets large, interior point methods become impractical in terms of both computational time and memory…

Optimization and Control · Mathematics 2023-11-27 Federico Battista , Marianna De Santis

In this paper, we compute the stationary states of the multicomponent phase-field crystal model by formulating it as a block constrained minimization problem. The original infinite-dimensional non-convex minimization problem is approximated…

Numerical Analysis · Mathematics 2021-07-16 Chenglong Bao , Chang Chen , Kai Jiang

This paper presents a novel sensitivity-based distributed programming (SBDP) approach for non-convex, large-scale nonlinear programs (NLP). The algorithm relies on first-order sensitivities to cooperatively solve the central NLP in a…

Optimization and Control · Mathematics 2026-03-30 Maximilian Pierer von Esch , Andreas Völz , Knut Graichen

We propose a new numerical scheme for approximating level-sets of Lipschitz multivariate functions which is robust to stochastic noise. The algorithm's main feature is an adaptive grid-based stochastic approximation strategy which…

Numerical Analysis · Mathematics 2025-09-19 Matteo Croci , Abdul-Lateef Haji-Ali , Ian C. J. Powell