Step 1 Creating a coarse mesh

Step 1 - Creating a coarse mesh

In this example we will build our first coarse mesh and write it to .vtu files in order to visualize it with Paraview.

You will find the code to this example in example/tutorials/step1_coarsemesh.c and it creates the executable example/tutorials/step1_coarsemesh.

What is a coarse mesh?

In order to build an adaptive mesh t8code actually manages two meshes. The coarse mesh (cmesh) and the forest mesh (forest).

The coarse mesh is the initial input that describes the geometrical and topological properties of the meshed domain. It is a classical unstructured mesh as it would be generated by a standard mesh generator such as gmsh. It can be as simple as a single hexahedron specifying a cube domain, or as complex as Billions of tetrahedra, prisms, pyramids and hexahedra describing an airplane geometry.

We view each element of the coarse mesh as the root of recursive refinement. The forest is the collection of these refined elements. Due to the tree-like nature of recursive refinement, we call the elements of the cmesh trees.

The cmesh will (usually) not change during a computation. A cmesh can be partitioned among the processes or each process can hold a copy of the complete cmesh.