Sessi MCP: Investigation of Communication Kernel in Nek5000

Important advantage of spectral element method is its meshing flexibility coming from spatial decomposition of simulation domain into a set of non-overlapping sub-domains. The solution continuity is in this case ensured by frequent exchange between element of the field values at the shared faces, edges and vertices. This is done by a so-called gather-scatter operator, which in Nek5000 is implemented in in gslib using MPI1 features. In collaboration with the University of Edinburgh (within the ExaFLOW project) we have developed a new version of communication kernel for Nek5000 based on the PGAS parallel programming model. The new library is written in UPC and is currently tested. In the future we are going to explore possibilities e.g. new features of MPI3 communication.

M1: Integration of PGAS based gslib with Nek5000 (December 2017)
M2: Exploring new MPI3 features in context of gslib (April 2018)