Xref: utzoo ont.events:1370 uw.talks:64 uw.cs.grad:59 Path: utzoo!lsuc!attcan!utgpu!watmath!maytag!water!wlrush From: wlrush@water.waterloo.edu (Wenchantress Wench Wendall) Newsgroups: ont.events,uw.talks,uw.cs.grad Subject: SCIENTIFIC COMPUTATIONS SEMINAR Keywords: Prof. Howard C. Elman, Dept. of Comp. Sci. Message-ID: <2748@water.waterloo.edu> Date: 9 Nov 89 14:28:34 GMT Distribution: ont Organization: U of Waterloo, Ontario Lines: 43 & Inst. for Adv. Comp. Studies will speak on... DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES SCIENTIFIC COMPUTATIONS SEMINAR -Thursday, November 16, 1989 Professor Howard C. Elman, Dept. of Computer Science and Institute for Advanced Computer Studies, University of Maryland, will speak on ``Iterative Methods for Cyclically Reduced Non-Self-Adjoint Linear Systems.'' TIME: 3:30 p.m. ROOM: DC 1304 ABSTRACT We study iterative methods for solving linear systems of the type arising from two-cyclic discretizations of non-self-adjoint two-dimensional elliptic partial differential equations. A prototype is the convection-diffusion equation. The methods consist of applying one step of cyclic reduction, resulting in a ``reduced system'' of half the order of the original discrete problem, combined with a block iterative technique for solving the reduced system. For constant coefficient problems, we present analytic bounds on the spectral radii of the iteration matrices in terms of cell Reynolds numbers that show the methods to be rapidly convergent. In addition, we describe numerical experiments that supplement the analysis and that indicate that the methods compare favourably with methods for solving the ``unreduced'' system. This work is joint with Gene Golub of Stanford University. November 6, 1989