Afivo: A framework for quadtree/octree AMR with shared-memory parallelization and geometric multigrid methods

Afivo is a framework for simulations with adaptive mesh refinement (AMR) on quadtree (2D) and octree (3D) grids. The framework comes with a geometric multigrid solver, shared-memory (OpenMP) parallelism and it supports output in Silo and VTK file formats. Afivo can be used to efficiently simulate AMR problems with up to about 10^8 unknowns on desktops, workstations or single compute nodes. For larger problems, existing distributed-memory frameworks are better suited. The framework has no built-in functionality for specific physics applications, so users have to implement their own numerical methods. The included multigrid solver can be used to efficiently solve elliptic partial differential equations such as Poisson’s equation. Afivo’s design was kept simple, which in combination with the shared-memory parallelism facilitates modification and experimentation with AMR algorithms. The framework was already used to perform 3D simulations of streamer discharges, which required tens of millions of cells.Afivo是一款用于在四叉树（2D）与八叉树（3D）网格上开展自适应网格细化（Adaptive Mesh Refinement, AMR）模拟的框架。该框架配备几何多重网格求解器，支持共享内存（OpenMP）并行计算，同时支持以Silo与VTK文件格式输出模拟结果。Afivo可在台式机、工作站或单个计算节点上高效模拟规模最高达约10^8个未知量的AMR问题；针对更大规模的问题，现有的分布式内存框架会更为适配。该框架未内置面向特定物理应用的功能，因此用户需自行实现对应的数值方法。其所集成的多重网格求解器可高效求解椭圆型偏微分方程，例如泊松方程。Afivo的设计力求简洁，结合共享内存并行特性，便于对AMR算法进行修改与实验探索。本框架已被用于开展流注放电的三维模拟，此类模拟需要数千万个计算网格单元。