Communications of the
Korean Mathematical Society
CKMS

ISSN(Print) 1225-1763 ISSN(Online) 2234-3024

Article

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Commun. Korean Math. Soc. 1995; 10(4): 981-995

Printed December 1, 1995

Copyright © The Korean Mathematical Society.

Convergence and breakdown study of krylov methods for nonsymmetric linear systems

Jae Heon Yun

Chungbuk National University

Abstract

This paper first establishes some conditions for preconditioner under which PGCR does not break down. ~Next, VPGCR algorithm whose preconditioners can be easily obtained is introduced and then its breakdown and convergence properties are discussed. Lastly, implementation details of VPGCR are described and then numerical results of VPGCR with a certain criterion guaranteeing no breakdown are compared with those of restarted GMRES.

Keywords: Krylov method, breakdown, preconditioner

MSC numbers: 65F10