caa a22 4500 378867350 CHVBK 20180305123401.0 cr unu---uuuuu 161128e20030901xx s 000 0 eng 10.1515/156939503322553081 doi (NATIONALLICENCE)gruyter-10.1515/156939503322553081 Khoromskij B. N. Max-Planck-Institute for Mathematics in the Sciences, Inselstr. 22-26, D-04103 Leipzig, Germany Hierarchical matrix approximation to Green's function via boundary concentrated FEM [Elektronische Daten] [B. N. Khoromskij] In the preceding paper [24], a method is described for an explicit hierarchical (ℋ-matrix) approximation to the inverse of an elliptic differential operator with piecewise constant/smooth coefficients in ℝ d . In the present paper, we proceed with the ℋ-matrix approximation to the Green function. Here, it is represented by a sum of an ℋ-matrix and certain correction term including the product of data-sparse matrices of hierarchical formats based on the so-called boundary concentrated FEM [26]. In the case of jumping coefficients with respect to non-overlapping domain decomposition, the approximate inverse operator is obtained as a direct sum of local inverses over subdomains and the Schur complement inverse on the interface corresponding to the boundary concentrated FEM. Our Schur complement matrix provides the cheap spectrally equivalent preconditioner to the conventional interface operator arising in the iterative substructuring methods by piecewise linear finite elements. Copyright 2003, Walter de Gruyter elliptic equations nationallicence BEM nationallicence FEM nationallicence data-sparse approximate inverse nationallicence hierarchical matrices nationallicence boundary concentrated hp-FEM nationallicence Journal of Numerical Mathematics Walter de Gruyter 11/3(2003-09-01), 195-223 1570-2820 11:3<195 2003 11 jnma https://doi.org/10.1515/156939503322553081 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/156939503322553081 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Khoromskij B. N. Max-Planck-Institute for Mathematics in the Sciences, Inselstr. 22-26, D-04103 Leipzig, Germany NATIONALLICENCE 773 0- Journal of Numerical Mathematics Walter de Gruyter 11/3(2003-09-01), 195-223 1570-2820 11:3<195 2003 11 jnma CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter