Codice 33/2010 Titolo Multilevel Schwarz Methods for Elliptic Partial Differential Equations Data 2010-11-08 Autore/i Migliorati, Giovanni; Quarteroni, Alfio Link Download full text Abstract We investigate multilevel Schwarz domain decomposition preconditioners, to efficiently solve linear systems arising from numerical discretizations of elliptic Partial Differential Equations by the fiite element method. In our analysis we deal with unstructured mesh partitions and with subdomain boundaries resulting from using the mesh partitioner. We start from two-level preconditioners with either aggregative or interpolative coarse level components, then we focus on a strategy to increase the number of levels. For all preconditioners, we consider the additive residual update and its multiplicative variants within and between levels. Moreover, we compare the preconditioners behaviour, regarding scalability and rate of convergence. Numerical results are provided for elliptic boundary-value problems, including a convection-diffusion problem when suitable stabilization becomes necessary.