SC²S Colloquium - June 25, 2014

Date:	Juni 25, 2014
Room:	02.07.023
Time:	3 pm, s.t.

Dominik Gutermuth: Application of space-filling curves on unstructured grids for simulations on a sphere

Historically, climate and weather simulations were usually computed on latitude-longitude grids. Although they provide several advantages, there are also some drawbacks, e.g. the so-called polar problem for simulations on earth-scale. Therefore, the use of alternative grids is of growing interest. In this thesis, the two most promising alternatives are used: cubed sphere and hexagonal grids.

For simulations on HPC architectures, the consideration of the memory hierarchy successively got a crucial point for performance improvements. Space-filling curves (SFCs) provide several beneficial properties such as spatial and temporal locality. We use three different SFCs to reorder the originally created grid data (i.e. faces, edges and vertices). The reordering of the grid primitives is evaluated with a serial and parallel shallow water simulation which is computed on a dual grid.

The results show, that hexagonal grids can be improved, while the straight-forward grid generation for cubed sphere grids already provides a proper order.