Implementation of hybrid total FETI (HTFETI) solver for multi-core architectures

Abstract

We describe the implementation and the performance and scalability results of a hybrid FETI (Finite Element Tearing and Interconnecting) solver based on our variant of the FETI type domain decomposition method called Total FETI. In our approach a small number of neighboring subdomains is aggregated into clusters, which results into a smaller coarse problem. To solve the original problem Total FETI method is applied twice: to the clusters and then to the subdomains in each cluster.Current implementation of the solver is focused on the performance optimization of the main CG iteration loop, including: implementation of communication hiding and avoiding techniques for global communications; optimization of the nearest neighbor communication - multiplication with global gluing matrix; and optimization of the parallel CG algorithm to iterate over local Lagrange multipliers only.The performance is demonstrated on a linear elasticity synthetic 3D cube and real world benchmarks.