caa a22 4500 465751822 CHVBK 20180323111836.0 cr unu---uuuuu 170327e19900901xx s 000 0 eng 10.1007/BF02242922 doi (NATIONALLICENCE)springer-10.1007/BF02242922 Vassilevski P. Institute of Mathematics and Center of Computer Science and Technology, Bulgarian Academy of Sciences, "Acad. G. Bontchev” Str., Block 8, 1113, Sofia, Bulgaria aut On some ways of approximating inverses of banded matrices in connection with deriving preconditioners based on incomplete block factorizations [Elektronische Daten] [P. Vassilevski] Über einige Verfahren zur Approximation der Inversen von Bandmatrizen im Zusammenhang mit der Konstruktion von Präkonditionierungsmatrizen auf der Grundlage unvollständiger Blockfaktorisierungen A unified approach of deriving band approximate inverses of band symmetric positive definite matrices is considered. Such band approximations to the inverses of successive Schur complements are required throughout incomplete block factorizations of block-tridiagonal matrices. Such block-tridiagonal matrices arise, for example, in finite element solution of second order elliptic differential equations. A sharp decay rate estimate for inverses of blocktridiagonal symmetric positive definite matrices is given in addition. Numerical tests on a number of model elliptic boundary value problems are presented comparing thus derived preconditioning matrices. Springer-Verlag, 1990 incomplete factorization nationallicence approximate inverses nationallicence band matrices nationallicence block-tridiagonal matrices nationallicence decay rate estimates nationallicence finite elements nationallicence elliptic problems nationallicence preconditioned conjugate gradients nationallicence Computing Springer-Verlag 43/3(1990-09-01), 277-296 0010-485X 43:3<277 1990 43 607 https://doi.org/10.1007/BF02242922 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02242922 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Vassilevski P. Institute of Mathematics and Center of Computer Science and Technology, Bulgarian Academy of Sciences, "Acad. G. Bontchev” Str., Block 8, 1113, Sofia, Bulgaria aut NATIONALLICENCE 773 0- Computing Springer-Verlag 43/3(1990-09-01), 277-296 0010-485X 43:3<277 1990 43 607 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer