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Perhaps the most powerful method for deriving the Newtonian gravitational interaction between two masses is the multipole expansion. Once inner multipoles are calculated for a particular shape this shape can be rotated, translated, and even…

General Relativity and Quantum Cosmology · Physics 2020-01-01 Julian Stirling , Stephan Schlamminger

A P3M (Particle-Particle, Particle-Mesh) algorithm to compute the gravitational force on a set of particles is described. The gravitational force is computed using Fast Fourier Transforms. This leads to an incorrect force when the distance…

Astrophysics · Physics 2009-10-22 T. Theuns

We present a numerical framework for computing nested quadrature rules for various weight functions. The well-known Kronrod method extends the Gauss-Legendre quadrature by adding new optimal nodes to the existing Gauss nodes for integration…

Numerical Analysis · Mathematics 2018-08-14 Vahid Keshavarzzadeh , Robert M. Kirby , Akil Narayan

We have developed an adaptive multigrid code for solving the Poisson equation in gravitational simulations. Finer rectangular subgrids are adaptively created in locations where the density exceeds a local level-dependent threshold. We…

Astrophysics · Physics 2015-06-24 I. Suisalu , E. Saar

We demonstrate the high accuracy of the density splitting method to compute the gravitational potential and field in the plane of razor-thin, axially symmetric discs, as preliminarily outlined in Pierens & Hure (2004). Because residual…

Astrophysics · Physics 2009-11-10 Jean-Marc Hure , Arnaud Pierens

Autonomous materials discovery with desired properties is one of the ultimate goals for materials science, and the current studies have been focusing mostly on high-throughput screening based on density functional theory calculations and…

We consider robust covariance estimation with group symmetry constraints. Non-Gaussian covariance estimation, e.g., Tyler scatter estimator and Multivariate Generalized Gaussian distribution methods, usually involve non-convex minimization…

Machine Learning · Statistics 2013-06-19 Ilya Soloveychik , Ami Wiesel

Gravitational-wave analyses depend heavily on waveforms that model the evolution of compact binary coalescences as seen by observing detectors. In many cases these waveforms are given by waveform approximants, models that approximate the…

General Relativity and Quantum Cosmology · Physics 2024-10-11 Quirijn Meijer , Sarah Caudill

This thesis introduces a set of methods for testing models of modified gravity using galaxy clusters. In particular, a technique for constraining models with a chameleon screening is introduced. In addition, the outlined technique is…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-18 Andrius Tamosiunas

This paper proposes a penalized composite likelihood method for model selection in colored graphical Gaussian models. The method provides a sparse and symmetry-constrained estimator of the precision matrix, and thus conducts model selection…

Methodology · Statistics 2020-04-06 Qiong Li , Xiaoying Sun , Nanwei Wang

Clustering techniques attempt to group objects with similar properties into a cluster. Clustering the nodes of an attributed graph, in which each node is associated with a set of feature attributes, has attracted significant attention.…

Computer Vision and Pattern Recognition · Computer Science 2020-09-15 Chaojie Ji , Hongwei Chen , Ruxin Wang , Yunpeng Cai , Hongyan Wu

Real-world applications of computational fluid dynamics often involve the evaluation of quantities of interest for several distinct geometries that define the computational domain or are embedded inside it. For example, design optimization…

Numerical Analysis · Mathematics 2023-08-08 Guglielmo Padula , Francesco Romor , Giovanni Stabile , Gianluigi Rozza

In this work, we present our classification algorithm to identify strong gravitational lenses from wide-area surveys using machine learning convolutional neural network; LensExtractor. We train and test the algorithm using a wide variety of…

Instrumentation and Methods for Astrophysics · Physics 2018-04-11 Milad Pourrahmani , Hooshang Nayyeri , Asantha Cooray

Machine learning interatomic potentials are revolutionizing large-scale, accurate atomistic modelling in material science and chemistry. Many potentials use atomic cluster expansion or equivariant message passing frameworks. Such frameworks…

Computational Physics · Physics 2024-07-31 Bingqing Cheng

This paper presents a method for approximate Gaussian process (GP) regression with tensor networks (TNs). A parametric approximation of a GP uses a linear combination of basis functions, where the accuracy of the approximation depends on…

Machine Learning · Statistics 2023-11-01 Clara Menzen , Eva Memmel , Kim Batselier , Manon Kok

Sparse and convolutional constraints form a natural prior for many optimization problems that arise from physical processes. Detecting motifs in speech and musical passages, super-resolving images, compressing videos, and reconstructing…

Computer Vision and Pattern Recognition · Computer Science 2014-06-11 Hilton Bristow , Simon Lucey

We present a novel approach to robust pose graph optimization based on Graduated Non-Convexity (GNC). Unlike traditional GNC-based methods, the proposed approach employs an adaptive shape function using B-spline to optimize the shape of the…

Robotics · Computer Science 2023-09-26 Seungwon Choi , Wonseok Kang , Jiseong Chung , Jaehyun Kim , Tae-wan Kim

The objective of this paper is to develop methods for solving image recovery problems subject to constraints on the solution. More precisely, we will be interested in problems which can be formulated as the minimization over a closed convex…

Optimization and Control · Mathematics 2012-12-12 Caroline Chaux , Jean-Christophe Pesquet , Nelly Pustelnik

In this paper we study proximal conditional-gradient (CG) and proximal gradient-projection type algorithms for a block-structured constrained nonconvex optimization model, which arises naturally from tensor data analysis. First, we…

Optimization and Control · Mathematics 2014-10-16 Bo Jiang , Shuzhong Zhang

The theoretical investigation of gas adsorption, storage, separation, diffusion and related transport processes in porous materials relies on a detailed knowledge of the potential energy surface of molecules in a stationary environment. In…

Chemical Physics · Physics 2025-01-30 Johannes K. Krondorfer , Christian W. Binder , Andreas W. Hauser