One component in Additive Schwarz Method (ASM) Domain Decomposition (DD) preconditioners [BPS89, SBG96] using inexact subdomain solvers [Boe89, HLM91] consists in an operator extending the boundary data into the interior of each subdomain, i.e., a homogeneous extension with respect to the differential operator given in that subdomain. This paper is concerned with the construction of cheap extension operators using multilevel nodal bases [Yse86, Xu89, BPX90, Osw94] from an implementation viewpoint. Additional smoothing sweeps in the extension operators further improve the condition number of the preconditioned system. The paper summarizes and improves results given in [HLMN94, Nep95, Haa97].
References in Abstract
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