|Description||Nek5000 with OpenACC|
The co-design team OpenACC in Nek5000 aims to enable Nek5000 efficiently to utilize the massively parallel GPU accelerated system based on OpenACC directive. Nek5000 is an open-source code for the simulation of incompressible flow in complex geometries. Nek5000 is written in mixed Fortran77/C and designed to employ fully large-scale parallelism.
In the present state, Nek5000 does not employ any hybrid approach to parallelization. All communication is handled by MPI, which has proven to be very efficient, mainly due to the element structure of the mesh . In  a Lattice Boltzmann code has been successfully adapted to use a large number of GPUs in parallel. In order to adapt the Nek5000 code for the exascale computation, a hybrid approach, that is, C with MPI for communication and OpenACC for GPU acceleration, should be considered.