The Power of Modular Tree-Based AMR - Resolving Hanging Nodes and Cutting Holes

Abstract

We discuss recent developments in scalable adaptive mesh refinement (AMR). The t8code library offers fast and efficient tree-based (space-filling curve) adaptive mesh refinement solutions for application codes that require meshes. t8code extends the space-filling curve (SFC) techniques from quadrilaterals and hexahedra to all element shapes via an abstract interface. In particular we offer implementations for vertices, lines, quads, triangles, tetrahedra, hexahedra, prisms and pyramids, and also support meshes including different element shapes. The abstract interface allows us to further extend the SFC techniques to non-standard use cases that enable fast and scalable AMR for a variety of use cases. In particular we present the feature deleting elements from the mesh and the feature subelements. Subelements itself are very powerful in that they allow for a variety of new AMR option. One application of us is to remove hanging nodes from quad based AMR. Other applications include the definition of boundary layer (for example around airfoils), anisotropic refinement or subgrids for GPU computations.