Parallel domain-decomposition-based algorithm of hybrid FE-BI-MLFMA method for 3-D scattering by large inhomogeneous objects

The hybrid method of the finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) has been recognized as one of the most powerful numerical methods for analyzing large inhomogeneous radiation/scattering problems. A domain decomposition algorithm (DDA) of FE-BI-MLFMA is presented in this paper by using the finite element tearing and interconnecting method (FETI). The formulation of DDA-FE-BI-MLFMA is presented and analyzed in detail. The numerical performance of DDA-FE-BI-MLFMA is investigated by numerical experiments from many aspects. It includes the convergence speed versus types of domain decomposition, number of subdomains, types and inhomogeneity of dielectrics involving in solved problems, and the scalability of DDA-FE-BI-MLFMA. The comparison of DDA and previous algorithms of FE-BI-MLMFMA is also carried out. Finally, the capability of DDA-FE-BI-MLFMA is shown for large inhomogeneous problems.