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Radiation-hydrodynamics (RHD) determines the bulk evolution and observable emission in a wide variety of high-energy astrophysical phenomena. Due to their complexity, RHD problems must usually be studied through numerical simulation. We…

High Energy Astrophysical Phenomena · Physics 2026-03-20 Itamar Giron , Menahem Krief , Nicholas C. Stone , Elad Steinberg

We have developed a simulation code with the techniques which enhance both spatial and time resolution of the PM method for which the spatial resolution is restricted by the spacing of structured mesh. The adaptive mesh refinement (AMR)…

Astrophysics · Physics 2009-11-06 Hideki Yahagi , Yuzuru Yoshii

Numerical evolution of the spherically symmetric, massive Klein-Gordon field is presented using a new adaptive mesh refinement (AMR) code with fourth order discretization in space and time, along with compactification in space. The system…

High Energy Physics - Theory · Physics 2009-11-11 Peter Csizmadia

We describe the CRASH (Center for Radiative Shock Hydrodynamics) code, a block adaptive mesh code for multi-material radiation hydrodynamics. The implementation solves the radiation diffusion model with the gray or multigroup method and…

Solar and Stellar Astrophysics · Physics 2015-05-27 B. van der Holst , G. Toth , I. V. Sokolov , K. G. Powell , J. P. Holloway , E. S. Myra , Q. Stout , M. L. Adams , J. E. Morel , R. P. Drake

We propose a path cover adaptive algebraic multigrid (PC-$\alpha$AMG) method for solving linear systems of weighted graph Laplacians and can also be applied to discretized second order elliptic partial differential equations. The…

Numerical Analysis · Mathematics 2018-06-20 Xiaozhe Hu , Junyuan Lin , Ludmil T. Zikatanov

Methods for solving hyperbolic systems typically depend on unknown ordering (e.g., Gauss-Seidel, or sweep/wavefront/marching methods) to achieve good convergence. For many discretisations, mesh types or decompositions these methods do not…

Numerical Analysis · Mathematics 2025-11-19 S. Dargaville , R. P. Smedley-Stevenson , P. N. Smith , C. C. Pain

We present a fourth-order projection method with adaptive mesh refinement (AMR) for numerically solving the incompressible Navier-Stokes equations (INSE) with subcycling in time. Our method features (i) a reformulation of INSE so that the…

Numerical Analysis · Mathematics 2025-09-08 Shubo Zhao , Qinghai Zhang

This work discusses the application of an affine reconstructed nodal DG method for unstructured grids of triangles. Solving the diffusion terms in the DG method is non-trivial due to the solution representations being piecewise continuous.…

Computational Physics · Physics 2021-04-20 Yang Song , Bhuvana Srinivasan

We provide a preliminary comparison of the dispersion properties, specifically the time-amplification factor, the scaled group velocity and the error in the phase speed of four spatiotemporal discretization schemes utilized for solving the…

Numerical Analysis · Mathematics 2019-12-23 S. Singh , S. Sircar

This paper develops a new algebraic multigrid (AMG) method for sparse least-squares systems of the form $A=G^TG$ motivated by challenging applications in scientific computing where classical AMG methods fail. First we review and relate the…

Numerical Analysis · Mathematics 2026-01-09 Ben S. Southworth , Hussam Al Daas , Golo A. Wimmer , Ed Threlfall

In this article, we present a novel approach for block-structured adaptive mesh refinement (AMR) that is suitable for extreme-scale parallelism. All data structures are designed such that the size of the meta data in each distributed…

Distributed, Parallel, and Cluster Computing · Computer Science 2018-07-24 Florian Schornbaum , Ulrich Rüde

We introduce a novel Unsmoothed Aggregation (UA) Algebraic Multigrid (AMG) method combined with Preconditioned Conjugate Gradient (PCG) to overcome the limitations of Extended Position-Based Dynamics (XPBD) in high-resolution and…

Graphics · Computer Science 2025-05-20 Chunlei Li , Peng Yu , Tiantian Liu , Siyuan Yu , Yuting Xiao , Shuai Li , Aimin Hao , Yang Gao , Qinping Zhao

We present an algorithm for solving the radiative transfer problem on massively parallel computers using adaptive mesh refinement and domain decomposition. The solver is based on the method of characteristics which requires an adaptive…

Astrophysics of Galaxies · Physics 2015-08-13 Lars Buntemeyer , Robi Banerjee , Thomas Peters , Mikhail Klassen , Ralph E. Pudritz

Obtainable computational efficiency is evaluated when using an Adaptive Mesh Refinement (AMR) strategy in time accurate simulations governed by sets of conservation laws. For a variety of 1D, 2D, and 3D hydro- and magnetohydrodynamic…

Astrophysics · Physics 2009-11-10 R. Keppens , M. Nool , G. Toth , J. P. Goedbloed

This work develops a nonlinear multigrid method for diffusion problems discretized by cell-centered finite volume methods on general unstructured grids. The multigrid hierarchy is constructed algebraically using aggregation of degrees of…

Numerical Analysis · Mathematics 2020-10-29 Chak Shing Lee , François Hamon , Nicola Castelletto , Panayot S. Vassilevski , Joshua White

We analyze the mixed frame equations of radiation hydrodynamics under the approximations of flux-limited diffusion and a thermal radiation field, and derive the minimal set of evolution equations that includes all terms that are of leading…

Astrophysics · Physics 2009-11-11 Mark R. Krumholz , Richard I. Klein , Christopher F. McKee , John Bolstad

In this paper, the general procedure to solve the General Relativistic Hydrodynamical(GRH) equations with Adaptive-Mesh Refinement (AMR) is presented. In order to achieve, the GRH equations are written in the conservation form to exploit…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Orhan Donmez

We have implemented non-ideal Magneto-Hydrodynamics (MHD) effects in the Adaptive Mesh Refinement (AMR) code RAMSES, namely ambipolar diffusion and Ohmic dissipation, as additional source terms in the ideal MHD equations. We describe in…

Solar and Stellar Astrophysics · Physics 2015-10-22 J. Masson , R. Teyssier , C. Mulet-Marquis , P. Hennebelle , G. Chabrier

We present a new numerical tool for solving the special relativistic ideal MHD equations that is based on the combination of the following three key features: (i) a one-step ADER discontinuous Galerkin (DG) scheme that allows for an…

High Energy Astrophysical Phenomena · Physics 2015-08-12 Olindo Zanotti , Francesco Fambri , Michael Dumbser

Diffusion models (DMs) have shown promising results on single-image super-resolution and other image-to-image translation tasks. Benefiting from more computational resources and longer inference times, they are able to yield more realistic…

Computer Vision and Pattern Recognition · Computer Science 2024-10-24 Yuanting Fan , Chengxu Liu , Nengzhong Yin , Changlong Gao , Xueming Qian