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Context. The pursuit of more realistic spectroscopic modelling and consistent abundances has led us to begin a new series of papers designed to improve current solar and stellar abundances of various atomic species. To achieve this, we have…

Solar and Stellar Astrophysics · Physics 2020-02-12 A. J. Gallagher , M. Bergemann , R. Collet , B. Plez , J. Leenaarts , M. Carlsson , S. A. Yakovleva , A. K Belyaev

We present the package SADE (Symmetry Analysis of Differential Equations) for the determination of symmetries and related properties of systems of differential equations. The main methods implemented are: Lie, nonclassical, Lie-B\"acklund…

Mathematical Physics · Physics 2015-05-18 Tarcí sio M. Rocha Filho , Annibal Figueiredo

In several recent works \cite{Causley2013a}, \cite{Causley2013}, we developed a new second order, A-stable approach to wave propagation problems based on the method of lines transpose (MOL$^T$) formulation combined with alternating…

Numerical Analysis · Mathematics 2013-08-15 Matthew F. Causley , Andrew J. Christlieb

Under a smart grid paradigm, there has been an increase in sensor installations to enhance situational awareness. The measurements from these sensors can be leveraged for real-time monitoring, control, and protection. However, these…

Systems and Control · Electrical Eng. & Systems 2022-11-09 Shweta Dahale , Sai Munikoti , Balasubramaniam Natarajan , Rui Yang

This paper presents an efficient parallel method for the deterministic solution of the 3D stationary Boltzmann transport equation applied to diffusive problems such as nuclear core criticality computations. Based on standard…

Computational Physics · Physics 2017-10-05 Salli Moustafa , François Févotte , Mathieu Faverge , Laurent Plagne , Pierre Ramet

Bayesian simultaneous estimation of nonparametric quantile curves is a challenging problem, requiring a flexible and robust data model whilst satisfying the monotonicity or noncrossing constraints on the quantiles. This paper presents the…

Methodology · Statistics 2017-11-28 T. Rodrigues , J. -L. Dortet-Bernadet , Y. Fan

We present a new training methodology for transformers using a multilevel, layer-parallel approach. Through a neural ODE formulation of transformers, our application of a multilevel parallel-in-time algorithm for the forward and…

Machine Learning · Computer Science 2026-01-27 Shuai Jiang , Marc Salvadó-Benasco , Eric C. Cyr , Alena Kopaničáková , Rolf Krause , Jacob B. Schroder

In systems with a real Bloch Hamiltonian band nodes can be characterised by a non-Abelian frame-rotation charge. The ability of these band nodes to annihilate pairwise is path dependent, since by braiding nodes in adjacent gaps the sign of…

Quantum Gases · Physics 2024-09-02 Oliver Breach , Robert-Jan Slager , F. Nur Ünal

Newton's method is an ubiquitous tool to solve equations, both in the archimedean and non-archimedean settings -- for which it does not really differ. Broyden was the instigator of what is called "quasi-Newton methods". These methods use an…

Symbolic Computation · Computer Science 2020-09-04 Xavier Dahan , Tristan Vaccon

In this paper we present applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. According to variational approach in the general case we have the solution as a…

Accelerator Physics · Physics 2009-10-31 Antonina N. Fedorova , Michael G. Zeitlin , Zohreh Parsa

An iterative scheme can be used to find a steady-state solution to the Boltzmann equation, however, it is very slow to converge in the near-continuum flow regime. In this paper, a synthetic iterative scheme is developed to speed up the…

Computational Physics · Physics 2017-04-05 Lei Wu , Jun Zhang , Haihu Liu , Yonghao Zhang , Jason Reese

We describe an important addition to the parallel implementation of our generalized NLTE stellar atmosphere and radiative transfer computer program PHOENIX. In a previous paper in this series we described data and task parallel algorithms…

Astrophysics · Physics 2009-10-30 E. Baron , Peter H. Hauschildt

This review paper outlines background information and covers recent advances made via the analysis of spectra and images of prominence plasma and the increased sophistication of non-LTE (ie when there is a departure from Local Thermodynamic…

Solar and Stellar Astrophysics · Physics 2011-05-10 N. Labrosse , P. Heinzel , J. -C. Vial , T. Kucera , S. Parenti , S. Gunar , B. Schmieder , G. Kilper

This paper introduces a parallel-in-time algorithm for efficient steady-state solution of the eddy current problem. Its main idea is based on the application of the well-known multi-harmonic (or harmonic balance) approach as the coarse…

Computational Engineering, Finance, and Science · Computer Science 2019-11-07 Iryna Kulchytska-Ruchka , Herbert De Gersem , Sebastian Schöps

We consider an application of modification of our variational-wavelet approach to some nonlinear collective model of beam/plasma physics: Vlasov/Boltzmann-like reduction from general BBGKY hierachy related to modeling of propagation of…

Accelerator Physics · Physics 2007-05-23 Antonina N. Fedorova , Michael G. Zeitlin

We develop a model for the description of nonlinear pulse propagation in multimode optical fibers with a parabolic refractive index profile. It consists in a 1+1D generalized nonlinear Schr\"odinger equation with a periodic nonlinear…

Most existing random walk based network embedding methods often follow only one of two principles, homophily or structural equivalence. In real world networks, however, nodes exhibit a mixture of homophily and structural equivalence, which…

Social and Information Networks · Computer Science 2020-10-27 Chen Cui , Ning Yang , Philip S. Yu

Using nonparametric methods has been increasingly explored in Bayesian hierarchical modeling as a way to increase model flexibility. Although the field shows a lot of promise, inference in many models, including Hierachical Dirichlet…

Machine Learning · Statistics 2015-01-19 Alexander Spangher

Parallel implementations of linear iterative solvers generally alternate between phases of data exchange and phases of local computation. Increasingly large problem sizes on more heterogeneous systems make load balancing and network layout…

Numerical Analysis · Mathematics 2020-08-12 Christian Glusa , Paritosh Ramanan , Erik G. Boman , Edmond Chow , Sivasankaran Rajamanickam

3D detailed radiative transfer is computationally taxing, since the solution of the radiative transfer equation involves traversing the six dimensional phase space of the 3D domain. With modern supercomputers the hardware available for…

Solar and Stellar Astrophysics · Physics 2021-02-05 Peter H. Hauschildt , E. Baron