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We present a novel scheme to accurately predict atomic forces as vector quantities, rather than sets of scalar components, by Gaussian Process (GP) Regression. This is based on matrix-valued kernel functions, on which we impose the…

Chemical Physics · Physics 2017-06-14 Aldo Glielmo , Peter Sollich , Alessandro De Vita

We consider a compression method for boundary element matrices arising in the context of the computation of electrostatic fields. Green cross approximation combines an analytic approximation of the kernel function based on Green's…

Numerical Analysis · Mathematics 2018-10-22 Steffen Börm , Sven Christophersen

This paper introduces a novel motion planner, incrementally stochastic and accelerated gradient information mixed optimization (iSAGO), for robotic manipulators in a narrow workspace. Primarily, we propose the overall scheme of iSAGO…

Robotics · Computer Science 2022-07-20 Yichang Feng , Jin Wang , Haiyun Zhang , Guodong Lu

Coarse-Graining (CG) models are low resolution approximation of high resolution models, such as all-atomic (AA) models. An effective CG model is expected to reproduce equilibrium values of sufficient physical quantities of its AA model,…

Statistical Mechanics · Physics 2015-02-10 Shijing Lu , Xin Zhou

This paper presents a new parameter estimation algorithm for the adaptive control of a class of time-varying plants. The main feature of this algorithm is a matrix of time-varying learning rates, which enables parameter estimation error…

Optimization and Control · Mathematics 2021-11-18 Joseph E. Gaudio , Anuradha M. Annaswamy , Eugene Lavretsky , Michael A. Bolender

Variational symplectic algorithms have recently been developed for carrying out long-time simulation of charged particles in magnetic fields. As a direct consequence of their derivation from a discrete variational principle, these…

Plasma Physics · Physics 2015-06-18 Jonathan Squire , Hong Qin , William M. Tang

A novel and scalable geometric multi-level algorithm is presented for the numerical solution of elliptic partial differential equations, specially designed to run with high occupancy of streaming processors inside Graphics Processing…

Mathematical Software · Computer Science 2017-03-22 J. T. Becerra-Sagredo , F. Mandujano , C. Malaga

We present a new code, SCALAR, based on the high-resolution hydrodynamics and N-body code RAMSES, to solve the Schr\"odinger equation on adaptive refined meshes. The code is intended to be used to simulate axion or fuzzy dark matter models…

Computational Physics · Physics 2020-09-23 Mattia Mina , David F. Mota , Hans A. Winther

A fully variational, unstructured, electromagnetic particle-in-cell integrator is developed for integration of the Vlasov-Maxwell equations. Using the formalism of Discrete Exterior Calculus, the field solver, interpolation scheme and…

Plasma Physics · Physics 2015-06-18 Jonathan Squire , Hong Qin , William M. Tang

Translations or, more generally, coordinate transformations of scalar fields arise in several applications, such as weather, accretion disk and magnetized plasma turbulence modeling. In local studies of accretion disks and magnetized…

Plasma Physics · Physics 2021-10-07 Manaure Francisquez , Noah R. Mandell , Ammar Hakim , Gregory W. Hammett

Modeling molecular potential energy surface is of pivotal importance in science. Graph Neural Networks have shown great success in this field. However, their message passing schemes need special designs to capture geometric information and…

Machine Learning · Computer Science 2023-04-24 Xiyuan Wang , Muhan Zhang

We present an adaptive grid matrix-free operator approximation scheme based on a "product-convolution" interpolation of convolution operators. This scheme is appropriate for operators that are locally translation-invariant, even if these…

Numerical Analysis · Mathematics 2019-02-07 Nick Alger , Vishwas Rao , Aaron Myers , Tan Bui-Thanh , Omar Ghattas

We describe and implement an adaptive particle-mesh algorithm to solve the Poisson equation for grid-based hydrodynamics codes with nested grids. The algorithm is implemented and extensively tested within the astrophysical code Enzo against…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 Jean-Claude Passy , Greg L. Bryan

High-order Discontinuous Galerkin (DG) methods promise to be an excellent discretisation paradigm for partial differential equation solvers by combining high arithmetic intensity with localised data access. They also facilitate dynamic…

Mathematical Software · Computer Science 2020-06-02 Dominic E. Charrier , Benjamin Hazelwood , Tobias Weinzierl

We consider the parallel time integration of the linear advection equation with the Parareal and two-level multigrid-reduction-in-time (MGRIT) algorithms. Our aim is to develop a better understanding of the convergence behaviour of these…

Numerical Analysis · Mathematics 2019-10-15 Oliver A. Krzysik , Hans De Sterck , Scott P. MacLachlan , Stephanie Friedhoff

Adaptive regularization methods pre-multiply a descent direction by a preconditioning matrix. Due to the large number of parameters of machine learning problems, full-matrix preconditioning methods are prohibitively expensive. We show how…

Machine Learning · Computer Science 2020-11-19 Naman Agarwal , Brian Bullins , Xinyi Chen , Elad Hazan , Karan Singh , Cyril Zhang , Yi Zhang

Computationally expensive, high-accuracy detector simulations are a major bottleneck for many particle physics experiments such as those at the Large Hadron Collider (LHC) as well as those planned for future colliders. This challenge has…

Instrumentation and Detectors · Physics 2026-03-17 P. Alex May , Qibin Liu , Julia Gonski , Benjamin Nachman

Minimizing computational cost is one of the major challenges in the modelling and numerical analysis of hydrodynamics, and one of the ways to achieve this is by the use of quadtree grids. In this paper, we present an adaptive scheme on…

Numerical Analysis · Mathematics 2020-08-06 Mohammad A. Ghazizadeh , Abdolmajid Mohammadian

In this paper we describe an adaptive and multi-scale algorithm for the parsimonious fit of the corneal surface data that allows to adapt the number of functions used in the reconstruction to the conditions of each cornea. The method…

We have developed a hybrid code GMEC: Gyro-kinetic Magnetohydrodynamics (MHD) Energetic-particle Code that can numerically simulate energetic particle-driven Alfv\'en eigenmodes and energetic particle transport in tokamak plasmas. In order…

Plasma Physics · Physics 2024-02-23 Z. Y. Liu , P. Y. Jiang , S. Y. Liu , L. L. Zhang , G. Y. Fu
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