Xavier Claeys(LJLL) - Accelerating non-local exchange in generalized optimized Schwarz methods
Résumé de X. Claeys The generalized optimized Schwarz method proposed in [Claeys & Parolin, 2022] is a variant of the Després algorithm for solving harmonic wave problems where transmission conditions are enforced by means of a non-local exchange operator. Compared to the original Després algorithm where transmission conditions are expressed in terms of a simple swap of unknowns, which is easy to compute, this novel exchange operator induces a non-negligible additional computational cost. I shall present an easily implementable acceleration technique that significantly reduces this cost without any deterioration on the precision and convergence speed of the overall domain decomposition algorithm. It combines both preconditioning and recycling techniques. I will present numerical experiments and theoretical estimates. This is joint work with Roxane Atchekzai (SU/CEA) and Matthieu Lecouvez (CEA).