IBLU decompositions based on Padé approximants.

In this paper, we introduce a new class of frequency-filtering IBLU decompositions that use continued-fraction approximation for the diagonal blocks. This technique allows us to construct efficient frequency-filtering preconditioners for discretizations of elliptic partial differential equations on domains with non-trivial geometries. We prove theoretically for a class of model problems that the application of the proposed preconditioners leads to a convergence rate of up to 1-O(h^1/4) of the CG iteration. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]