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PRODID:-//ALOP - ECPv4.6.12//NONSGML v1.0//EN
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X-ORIGINAL-URL:https://alop.uni-trier.de
X-WR-CALDESC:Events for ALOP
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DTSTART;TZID=Europe/Berlin:20170515T160000
DTEND;TZID=Europe/Berlin:20170515T180000
DTSTAMP:20180322T172759
CREATED:20170403T131431Z
LAST-MODIFIED:20170427T082452Z
UID:1158-1494864000-1494871200@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Prof. Andreas Frommer
DESCRIPTION:On Monday\, May 15 2017\, Prof. Andreas Frommer of Bergische Universität Wuppertal will join the ALOP-Colloquium and present his recent work entitled \n \nMatrix functions – computation and convergence for Krylov subspace based methods \nAbstract: f(A)b\, the action of the function f of a matrix A on a vector b\, is required in many applications\, for example in exponential integrators\, where f = exp or in lattice QCD where f(z) = z-α; α ϵ (0\, 1). Typically\, A is large and sparse\, so computing f(A) directly is not possible\, but subspace techniques allow to approximate f(A)b. In this talk will address issues related to the computation and to theconvergence analysis for Krylov subspace based methods. The outstanding problem in computation is how to obtain a stable restart procedure\, and we show how this can be achieved when f can be adequately represented by a contour integral. On the analytical side\, we present convergence results when f is a Stieltjes function and A is symmetric and positive denite and\, with appropriate modications\, when A is just positive denite but not necessarily symmetric. Finally\, we will address generalizations to the block case\, i.e. when several vectors b are to be treated simultaneously. \nThe presentation will take place in HS 9 \nWe will meet over coffee in E10 at 15:45 \n
URL:https://alop.uni-trier.de/event/alop-colloquium-with-prof-frommer/
LOCATION:Universitätsring 15\, Trier\, 54296\, Germany
CATEGORIES:kolloquium
ORGANIZER;CN="Research%20Training%20Group%20ALOP%20at%20Trier%20University":MAILTO:alop@uni-trier.de
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