Dozenten: | Matthias Bollhöfer, Christian Mehl, Volker Mehrmann, Reinhard Nabben, Caren Tischendorf, Harry Yserentant |
Koordination: | Christian Mehl |
LV-Termine: | Do 10:00-11:00 oder Do 10:00-12:00 in MA 313 |
Inhalt: | Vorträge von Diplomanden, Doktoranden, Postdocs und manchmal auch Gästen zu aktuellen Forschungsthemen |
Vollständige vorläufige Terminplanung: | ||||
Datum | Uhrzeit | Raum | Vortragende(r) | Titel |
---|---|---|---|---|
Do 21.10.2004 | 10:00 | MA 313 |
Vorbesprechung | |
im An- schluss |
MA 313 |
Timo Reis | Infinite dimensional descriptor systems | |
Do 28.10.2004 | 10:00 | MA 313 |
Petr Tichy | Towards understanding the convergence of GMRES (Abstract) |
Do 11.11.2004 | 10:00 | MA 313 |
Christian Schröder |
The Riccati method for solving standard eigenvalue problems |
im An- schluss |
MA 313 |
Lena Wunderlich | Numerical Solution of Second Order Differential-Algebraic Equations | |
Do 25.11.2004 | 10:00 | MA 313 |
Andreas Zeiser | Fundamentals of phonon-induced relaxation of hot electrons |
im An- schluss |
MA 313 |
Christian Otto | Restarting the Second-Order Arnoldi Method and Restarting and Locking the Quadratic Jacobi-Davidson Method | |
Do 9.12.2004 | 10:00 | MA 313 |
Michael Schmidt | Model reduction via the discretization of input-output mappings |
Do 16.12.2004 | 10:00 | MA 366 |
Falk Ebert | Electrical Circuits in a Nutshell -- Part 1: Currents and Flows |
im An- schluss |
MA 366 |
Simone Bächle | Electrical Circuits in a Nutshell -- Part 2: Circuits and Graphs | |
Do 20.1.2005 | 10:00 | MA 313 |
Britta Leupold | Stability of Linear ODEs |
Do 27.1.2005 | 10:00 | MA 313 |
Sonja Schlauch | Simulation of the flow in a stirred tank using Featflow |
im An- schluss |
MA 313 |
Ulrike Baur | Factorized solution of Sylvester equations | |
Do 3.2.2005 | 10:00 | MA 313 |
Caren Tischendorf | Stability preserving integration of DAEs |
Do 10.2.2005 | 10:00 | MA 313 |
Christian Mense | Coarsing Strategies for Algebraic Multigrid Methods |
Interessenten sind herzlich eingeladen!
Weitere Vorträge siehe auch:
Abstracts zu manchen Vorträgen:
Abstract:
Understanding the convergence behavior of the GMRES method for
solving linear algebraic systems has been a challenging research
topic for the last two decades. In this talk we present recent
results on the algorithm's behavior for systems with normal
coefficient matrices as well as for systems with a single Jordan
block. We concentrate on the worst-case behavior of the GMRES
residual norm.
For normal matrices, the worst-case behavior is described by a min-max approximation problem on the discrete set of the matrix eigenvalues. We will discuss how to evaluate or estimate this min-max approximation, and if it is possible to characterize the GMRES-related quantities that lead to the worst-case behavior.
For nonnormal matrices, the situation is more complicated. In general, no sharp bound in the GMRES residual norms is known, that depends on properties of the matrix only . However, in many cases the worst-case GMRES behavior is characterized by the so-called ideal GMRES approximation problem, introduced by Greenbaum and Trefethen. Evaluation or estimation of this ideal GMRES approximation in general still represents an open problem. We investigate this problem for a Jordan block, the prototype of a nonnormal matrix.
Impressum | Christian Mehl 28.10.2004 |