TY - GEN A1 - Roitzsch, Rainer A1 - Kornhuber, Ralf T1 - BOXES - a Program to Generate Triangulations from a Rectangular Domain Description. N2 - BOXES computes a triangulation from a 2D domain description which consists of an arbitrary set of rectangles. Each rectangle may have attributes to control the triangulating process, define subdomain classes, or specify boundary conditions. The output of the program can be used as a coarse grid for KASKADE or one of its variants. Additional features are extensive checking of the user input, graphical display, and simple editing. T3 - ZIB-Report - TR-90-09 Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-4738 ER - TY - GEN A1 - Bornemann, Folkmar A. A1 - Erdmann, Bodo A1 - Roitzsch, Rainer T1 - KASKADE - Numerical Experiments. N2 - The C-implementation of KASKADE, an adaptive solver for linear elliptic differential equations in 2D, is object of a set of numerical experiments to analyze the use of resources (time and memory) with respect to numerical accuracy. We study the dependency of the reliability, robustness, and efficiency of the program from the parameters controlling the algorithm. T3 - ZIB-Report - TR-91-01 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-4762 ER - TY - JOUR A1 - Ackermann, Jörg A1 - Erdmann, Bodo A1 - Roitzsch, Rainer T1 - A self-adaptive multilevel finite element method for the stationary Schrödinger equation in three space dimensions JF - J. Chem. Phys. Y1 - 1994 VL - 101 SP - 7643 EP - 7650 ER - TY - CHAP A1 - Beck, Rudolf A1 - Erdmann, Bodo A1 - Roitzsch, Rainer ED - Arge, Erlend ED - Bruaset, Are Magnus ED - Langtangen, Hans Petter T1 - An Object-Oriented Adaptive Finite Element Code T2 - Modern Software Tools for Scientific Computing Y1 - 1997 SP - 105 EP - 124 PB - Birkhäuser, Boston ER - TY - GEN A1 - Galliat, Tobias A1 - Deuflhard, Peter A1 - Roitzsch, Rainer A1 - Cordes, Frank T1 - Automatic Identification of Metastable Conformations via Self-Organized Neural Networks N2 - As has been shown recently, the identification of metastable chemical conformations leads to a Perron cluster eigenvalue problem for a reversible Markov operator. Naive discretization of this operator would suffer from combinatorial explosion. As a first remedy, a pre-identification of essential degrees of freedom out of the set of torsion angles had been applied up to now. The present paper suggests a different approach based on neural networks: its idea is to discretize the Markov operator via self-organizing (box) maps. The thus obtained box discretization then serves as a prerequisite for the subsequent Perron cluster analysis. Moreover, this approach also permits exploitation of additional structure within embedded simulations. As it turns out, the new method is fully automatic and efficient also in the treatment of biomolecules. This is exemplified by numerical results. T3 - ZIB-Report - 00-51 KW - biochemical conformations KW - cluster analysis KW - Molecular Dynamics KW - Monte-Carlo methods KW - operator discretization KW - Perron cluster Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6197 ER -