Modular design

Algorithm

Physics

Computer graphics (images)

Adaptive mesh refinement

Mathematical analysis

Finite element method

Cartesian coordinate system

Parallel computing

Programming language

Geometry

Bandwidth (computing)

Computer network

Polygon mesh

Mathematics

Computer science

Computation

Computational science

Multiphysics

Quantum mechanics

Discretization

Integrator

Thermodynamics

Curvilinear coordinates

The Astrophysical Journal Supplement Series

The design and implementation of a new framework for adaptive mesh refinement (AMR) calculations is described. It is intended primarily for applications in astrophysical fluid dynamics, but its flexible and modular design enables its use for a wide variety of physics. The framework works with both uniform and nonuniform grids in Cartesian and curvilinear coordinate systems. It adopts a dynamic execution model based on a simple design called a "task list" that improves parallel performance by overlapping communication and computation, simplifies the inclusion of a diverse range of physics, and even enables multiphysics models involving different physics in different regions of the calculation. We describe physics modules implemented in this framework for both non-relativistic and relativistic magnetohydrodynamics (MHD). These modules adopt mature and robust algorithms originally developed for the Athena MHD code and incorporate new extensions: support for curvilinear coordinates, higher-order time integrators, more realistic physics such as a general equation of state, and diffusion terms that can be integrated with super-time-stepping algorithms. The modules show excellent performance and scaling, with well over 80% parallel efficiency on over half a million threads. The source code has been made publicly available.

The Athena++ Adaptive Mesh Refinement Framework: Design and Magnetohydrodynamic Solvers