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We present a study of shearfree gravitational collapse using cylindrically symmetric spacetimes whose interior is a non-rotating dissipative fluid bounded by a cylindrical hypersurface beyond which is an Einstein-Rosen vacuum exterior. We…

General Relativity and Quantum Cosmology · Physics 2025-04-23 Marie-Noëlle Célérier , Nilton O. Santos

Sinc-collocation methods are known to be efficient for Fredholm integral equations of the second kind, even if functions in the equations have endpoint singularity. However, existing methods have the disadvantage of inconsistent collocation…

Numerical Analysis · Mathematics 2025-07-10 Tomoaki Okayama

The present work introduces a simple, yet effective particle coalescing procedure for two-dimensional SPH simulations with spatially varying resolution. In addition to the regular conservation properties of former algorithms concerning the…

Computational Physics · Physics 2019-09-24 Balázs Havasi-Tóth

Contradicting results have been reported in the literature with respect to the performance of the numerical techniques employed for the study of supersonic turbulence. We aim at characterising the performance of different particle-based and…

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 present a reduced basis technique for long-time integration of parametrized incompressible turbulent flows. The new contributions are threefold. First, we propose a constrained Galerkin formulation that corrects the standard Galerkin…

Numerical Analysis · Mathematics 2017-10-11 Lambert Fick , Yvon Maday , Anthony T Patera , Tommaso Taddei

We develop an Euler-type particle method for the simulation of a McKean--Vlasov equation arising from a mean-field model with positive feedback from hitting a boundary. Under assumptions on the parameters which ensure differentiable…

Numerical Analysis · Mathematics 2018-05-31 Vadim Kaushansky , Christoph Reisinger

We introduce vertex block descent, a block coordinate descent solution for the variational form of implicit Euler through vertex-level Gauss-Seidel iterations. It operates with local vertex position updates that achieve reductions in global…

Graphics · Computer Science 2024-06-04 Anka He Chen , Ziheng Liu , Yin Yang , Cem Yuksel

Particle-in-cell codes are the most widely used simulation tools for kinetic studies of ultra-intense laser-plasma interactions. Using the motion of a single electron in a plane electromagnetic wave as a benchmark problem, we show…

Plasma Physics · Physics 2021-04-07 Kavin Tangtartharakul , Guangye Chen , Alexey Arefiev

Modeling core-collapse supernovae (CCSNe) with neutrino transport in three dimensions (3D) requires tremendous computing resources and some level of approximation. We present a first comparison study of CCSNe in 3D with different physics…

We have developed a parallel cosmological hydrodynamic simulation code designed for the study of formation and evolution of cosmological structures. The gravitational force is calculated using the TreePM method and the hydrodynamics is…

Astrophysics of Galaxies · Physics 2017-01-18 Jihye Shin , Juhan Kim , Sungsoo S. Kim , Changbom Park

Robust and efficient solvers for coupled-adjoint linear systems are crucial to successful aerostructural optimization. Monolithic and partitioned strategies can be applied. The monolithic approach is expected to offer better robustness and…

Numerical Analysis · Mathematics 2023-09-25 Christophe Blondeau , Mehdi Jadoui

We propose an effective and flexible way to implement 2D and 3D elastoplastic problems in MATLAB using fully vectorized codes. Our technique is applied to a broad class of the problems including perfect plasticity or plasticity with…

Numerical Analysis · Mathematics 2018-09-07 Martin Čermák , Stanislav Sysala , Jan Valdman

A new particle-based sampling and approximate inference method, based on electrostatics and Newton mechanics principles, is introduced with theoretical ground, algorithm design and experimental validation. This method simulates an…

Artificial Intelligence · Computer Science 2024-07-01 Yongchao Huang

We develop an algorithm for i) computing generalized regular $k$-point grids, ii) reducing the grids to their symmetrically distinct points, and iii) mapping the reduced grid points into the Brillouin zone. The algorithm exploits the…

Computational Physics · Physics 2019-07-01 Gus L. W. Hart , Jeremy J. Jorgensen , Wiley S. Morgan , Rodney W. Forcade

We review here the recent success in quantum annealing, i.e., optimization of the cost or energy functions of complex systems utilizing quantum fluctuations. The concept is introduced in successive steps through the studies of mapping of…

Quantum Physics · Physics 2010-09-21 Arnab Das , Bikas K. Chakrabarti

GenASiS (General Astrophysical Simulation System) is a new code being developed initially and primarily, though by no means exclusively, for the simulation of core-collapse supernovae on the world's leading capability supercomputers. This…

Instrumentation and Methods for Astrophysics · Physics 2015-07-09 Christian Y. Cardall , Reuben D. Budiardja , Eirik Endeve , Anthony Mezzacappa

We evaluate an efficient overset grid method for two-dimensional and three-dimensional particulate flows for small numbers of particles at finite Reynolds number. The rigid particles are discretised using moving overset grids overlaid on a…

Computational Physics · Physics 2017-05-24 A. R. Koblitz , S. Lovett , N. Nikiforakis , W. D. Henshaw

A new computational method is presented for study suspensions of charged soft particles undergoing fluctuating hydrodynamic and electrostatic interactions. The proposed model is appropriate for polymers, proteins and porous particles…

Soft Condensed Matter · Physics 2015-04-14 Juan P. Hernandez-Ortiz , Juan J. de Pablo

The applicability of the highly idealized secondary infall model to `realistic' initial conditions is investigated. The collapse of proto-halos seeded by $3\sigma$ density perturbations to an Einstein--de Sitter universe is studied here for…

Astrophysics · Physics 2009-10-28 Saleem Zaroubi , Avi Naim , Yehuda Hoffman