A comparison of element agglomeration algorithms for unstructured geometric multigrid

This paper compares the performance of seven different element agglomeration algorithms on unstructured triangular/tetrahedral meshes when used as part a geometric multigrid. Five these come from literature AMGe multigrid and mesh partitioning methods. The resulting schemes are tested matrix-free two problems in 2D 3D taken radiation transport applications; one which is diffusion limit. In dimensions all coarsening result methods perform similarly, but three aggressive performed by METIS produces shortest runtimes setup times.