EUFORIA HPC: Massive Parallelisation for Fusion Community

One of the central tasks of EUFORIA is to port, parallelise, and optimise fusion simulation codes, developed at individual research institutes in Europe. There are three supercomputer centres involved in the project located at Barcelona, Edinburgh, and Helsinki. For some of the fusion codes simply porting them to one of the supercomputers represents a major advancement in the use of the codes, as they until now have mainly been used by a small user community, or even exclusively by the author of the code. Also, where codes currently can only use one processor (i. e. are serial) providing any parallel functionality can be of major benefit to the code and the code owner(s). Many of the simulation codes for edge and core transport modelling of fusion plasma using high performance computing are estimated to currently require weeks or months of execution time to simulate science at a scale required to model the new fusion reactor ITER, and therefore these codes have to be optimised to run as fast as possible and parallelised in such a way that computer resources are used as effectively as possible. During the first fifteen month of the project, we have successfully ported eleven fusion codes to the supercomputers in Barcelona, Edinburgh and Helsinki. The installation procedure, library requirements and runtime scripts have been documented for each code, and deposited in the EUFORIA software repository and code revision system. Following this a number of these codes have been chosen for code optimisation and improvements in parallelisation and this paper outlines the experience that we have had with some of these codes, the performance improvements achieved, and the techniques used.