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General (tele)parallel Relativity, G$_\parallel$R, is the relativistic completion of Einstein's theories of gravity. The focus of this article is the derivation of the homogeneous and isotropic solution in G$_\parallel$R. The…

General Relativity and Quantum Cosmology · Physics 2023-10-18 Débora Aguiar Gomes , Jose Beltrán Jiménez , Tomi S. Koivisto

We present an efficient numerical code based on spectral methods to integrate the field equations of general Robinson-Trautmann spacetimes. The most natural basis functions for the spectral expansion of the metric functions are spherical…

General Relativity and Quantum Cosmology · Physics 2011-11-10 H. P. de Oliveira , E. L. Rodrigues , J. E. F. Skea

Elliptic equations play a crucial role in turbulence models for magnetic confinement fusion. Regardless of the chosen modeling approach - whether gyrokinetic, gyrofluid, or drift-fluid - the Poisson equation and Amp\`{e}re's law lead to…

Logically constrained rewrite systems (LCTRSs) are a versatile and efficient rewriting formalism that can be used to model programs from various programming paradigms, as well as simplification systems in compilers and SMT solvers. In this…

Computational Complexity · Computer Science 2020-12-14 Sarah Winkler , Georg Moser

In recent years, Graph Neural Networks (GNNs) have been utilized for various applications ranging from drug discovery to network design and social networks. In many applications, it is impossible to observe some properties of the graph…

Machine Learning · Computer Science 2025-03-12 Moshe Eliasof , Md Shahriar Rahim Siddiqui , Carola-Bibiane Schönlieb , Eldad Haber

New General Relativity (NGR) is a class of teleparallel theories defined by three free parameters, effectively reduced to two after appropriate normalization, which are subject to experimental constraints. In this framework, matter couples…

General Relativity and Quantum Cosmology · Physics 2026-04-20 D. F. López , A. A. Coley , R. J. van den Hoogen

We resolve a longstanding open problem in the computational modeling of nonlinear plates by introducing a numerical method that exactly enforces the isometry constraint, namely, that the first fundamental form of the mid-surface coincides…

Numerical Analysis · Mathematics 2026-05-11 Brendan Keith , Frédéric Marazzato

micrOMEGAs is a code to compute dark matter observables in generic extensions of the standard model. This new version of micrOMEGAs is a major update which includes a generalization of the Boltzmann equations to accommodate models with…

High Energy Physics - Phenomenology · Physics 2015-06-15 G. Belanger , F. Boudjema , A. Pukhov , A. Semenov

We describe a new interactive database (GRDB) of geometric objects in the general area of differential geometry. Database objects include, but are not restricted to, exact solutions of Einstein's field equations. GRDB is designed for…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Mustapha Ishak , Kayll Lake

The parabolic-hyperbolic form of the constraints is integrated numerically. The applied numerical stencil is $4^{th}$ order accurate (in the spatial directions) while 'time'-integration is made by using the method of lines with a $4^{th}$…

General Relativity and Quantum Cosmology · Physics 2022-01-13 Anna Nakonieczna , Łukasz Nakonieczny , István Rácz

Solving the trust-region subproblem (TRS) plays a key role in numerical optimization and many other applications. The generalized Lanczos trust-region (GLTR) method is a well-known Lanczos type approach for solving a large-scale TRS. The…

Numerical Analysis · Mathematics 2021-04-13 Zhongxiao Jia , Fa Wang

We solve for single distorted black hole initial data using the puncture method, where the Hamiltonian constraint is written as an elliptic equation in R^3 for the nonsingular part of the metric conformal factor. With this approach we can…

General Relativity and Quantum Cosmology · Physics 2009-11-10 J. David Brown , Lisa L. Lowe

We construct exact initial data for closed cosmological models filled with regularly arranged black holes in the presence of $\Lambda$. The intrinsic geometry of the 3-dimensional space described by this data is a sum of simple closed-form…

General Relativity and Quantum Cosmology · Physics 2017-03-15 Jessie Durk , Timothy Clifton

Kernel Regularized Least Squares (KRLS) is a popular method for flexibly estimating models that may have complex relationships between variables. However, its usefulness to many researchers is limited for two reasons. First, existing…

Machine Learning · Statistics 2023-09-12 Qing Chang , Max Goplerud

This article presents GRFsaw, an open-source software for generating two-phase (binary) microstructures with user-defined structural properties. Unlike most standard software for microstructure generation, GRFsaw is based on the concept of…

Computational Engineering, Finance, and Science · Computer Science 2024-12-09 Lars Blatny , Henning Löwe , Johan Gaume

Tensor time series (TTS) data, a generalization of one-dimensional time series on a high-dimensional space, is ubiquitous in real-world scenarios, especially in monitoring systems involving multi-source spatio-temporal data (e.g.,…

Machine Learning · Computer Science 2023-06-08 Jiewen Deng , Jinliang Deng , Renhe Jiang , Xuan Song

We study spherically symmetric geometries made of anisotropic perfect fluid based on general relativity. The purpose of the work is to find and classify black hole solutions in closed spacetime. In a general setting, we find that a static…

General Relativity and Quantum Cosmology · Physics 2017-10-04 Hyeong-Chan Kim

A new variant of the GMRES method is presented for solving linear systems with the same matrix and subsequently obtained multiple right-hand sides. The new method keeps such properties of the classical GMRES algorithm as follows. Both bases…

Numerical Analysis · Mathematics 2024-12-17 S. Sukmanyuk , D. Zheltkov , B. Valiakhmetov

We present three parameters exact solutions with possible black holes in $% 2+1-$dimensional $f\left( R\right) =R^{n}$ modified gravity coupled minimally to a cloud of strings. These three parameters are $n,$ the cloud of string coupling…

General Relativity and Quantum Cosmology · Physics 2016-02-26 S. Habib Mazharimousavi , M. Halilsoy

An application design is offered, which students of physics can use when authoring a solver for mechanical systems with constraints. A 'chainlist' concept is introduced to capture a constrained mechanical system configuration and to pass…

Physics Education · Physics 2015-03-17 Vladimir Vasilich Tregub
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