Large electromagnetic simulation by hybrid approach on large-scale parallel computing systems

International audienceThis paper deals with the parallel computing and computation time prediction applied to computational electromagnetics based on rigorous methods for large and complex structures, such as tunnels and airplane cabins. The main objective of this work is represented by the electromagnetic computation of an airplane cabin in order to characterize the propagation channel for a given frequency inside the structure. A well‐known three‐dimensional numerical method, transmission‐line matrix, is adopted for this work. Transmission‐line matrix modelling method is applied to volumes, using the symmetrical condensed node. The planar structures are modelled with the mode matching approach. In order to analyse the electromagnetic field at high frequencies inside large structures as an airplane cabin, the transmission‐line matrix mesh step is very small compared with the size of the physical structure. Thus, the total amount of data that need to be processed exceeds the RAM memory presented on a traditional computing machine. The implementation of the parallel transmission‐line matrix algorithm is a viable solution to this problem taking full advantage of the parallel and distributed architectures, as clusters, grids and supercomputers. The results prove the benefits of the grid computing and supercomputer environments to solve electrically large structures. The parallel hybrid approach, based on Message Passing Interface, is designed for Single Programme Multiple Data programming model. The study highlights the role of parallelization scheme, grid versus supercomputer, with respect to the size of the problem and its repartition. In order to access the computing resources available on different parallel computing platforms, users need to respect a charter containing time and resource number restrictions when doing reservations. So, a time prediction model based on the profile of the transmission‐line matrix algorithm has been developed to allow safe reservations of the computing nodes on grid environment. To have a good agreement between the measured and the predicted values for the computation time, the problem of the cache misses appearing during the simulation has been considered in the profile‐based prediction model of the transmission‐line matrix/modal hybrid application, according to the processor cache memory size. The maximum error for the estimated values of the computation times is about 6.09%. The relevance of this work is based on the fact that is given a complete tool to deal with the large electromagnetic structures: a parallel transmission‐line matrix implementation to take the advantage of the distributed architectures and a time prediction model in order to optimize the resource reservation and the simulation execution on the computing node