Optimization, Performance and Scalability Experiments of a Large Air Pollution Model by Using the EuroHPC Petascale Supercomputer DISCOVERER

An advanced parallel version of the Unified Danish Eulerian Model (UNI-DEM) has been implemented and optimized on the Bulgarian petascale supercomputer DISCOVERER, managed by EuroHPC-Bulgaria consortium. The machine is part of an emerging high performance infrastructure in the European Union. It unites the power of eight advanced supercomputer systems in different European countries. The results of some scalability experiments are shown in this paper. Two advanced highly parallel implementations of UNI-DEM (the MPI-only and a hybrid MPI-OpenMP) were used in the tests. These results are compared with similar results from experiments, performed on the Spanish supercomputer MareNostrum in BSC, the most powerful supercomputer in Spain (by that time – petascale, now upgraded to pre-exascale).