A new MOX Report entitled “Algebraic and Two-Level Parallel Substructured Schwarz Methods” by Ciaramella, G.; Gander, M.J.; Van Criekingen, S.; Vanzan, T. has appeared in the MOX Report Collection.
Check it out here: https://www.mate.polimi.it/biblioteca/add/qmox/60-2026.pdf
Abstract: Substructured Schwarz methods are interpretations of classical volume Schwarz methods as algorithms on interface variables. We introduce here a new parallel algebraic trace characterization to supersede the geometric identification of the substructure within our petscs-based implementation of the parallel Schwarz method (equivalent to RAS). We moreover consider a two-level substructured method with coarse space functions defined exclusively on the skeleton, and propose an additive version of the two-level preconditioner which significantly decreases the computing time. Weak scaling numerical results up to several thousands of CPU cores (one per subdomain) are presented for the one- and two-level methods, comparing substructured and classical volume methods.
