Frank Lübeck

Software

A large part of my work is devoted to the development of software packages. All published packages are free software in the sense that they are distributed with full source code and that it is allowed to reuse the code or to change and further develop it.

Computer Algebra

CHEVIE: I'm a co-developer of this computer algebra package for computing in and with Coxeter groups, Iwahori-Hecke algebras, Chevalley groups and related structures and their representations. This package is based on the systems GAP and Maple.
GAP: GAP is an internationally developed computer algebra system which allows applications in many areas of algebra. I'm participating in its development in various ways: Maintenance and further developments of the C-kernel, the documentation system, parts of the GAP library, interfaces to the GAP packages, ...; infrastructural work like Web/FTP server, distribution of GAP packages, releases of new versions, ...; as member of the GAP-Council; advice for the development of further packages; ...
EDIM - elementary divisors of integer matrices: A GAP package providing several functions for computing elementary divisors of large integer matrices. In particular there are implementations of the algorithms described in this article.
StandardFF - standard construction of finite fields and their cyclic subgroups: A GAP package implementing the constructions described in this article.
GAPDoc - writing GAP documentation: (with Max Neunhöffer) This is a meta-package for GAP, which defines a markup language for writing GAP documentation. It also provides programs for generating several output formats (text/PDF/HTML) from GAPDoc documents.
Browse - browsing tables in GAP: (with Thomas Breuer ) This is a meta GAP package which provides an interactive display of tables (e.g. character tables). It contains an interface to the ncurses-library which also makes many other applications possible.
FUtil - F's utilities: In this not yet officially released GAP package I'll distribute utilities for use with GAP.
Big GAP 3 Jobs, and Simplified GAP 3 Installation: A GAP 3 executable for Linux, slightly patched, optimized for i686 and statically linked for jobs of 2 GByte or more. A single GAP 3 archive with bug fixes applied, compiled manuals and some executables.
GAP Interface to SYMMETRICA programs computing Specht modules: The archive spechtSYMMETRICA.tar.gz contains GAP code using SYMMETRICA programs from here to compute matrices of Specht modules of symmetric groups. Unpacking creates a directory spechtSYMMETRICA, then read the INSTALL inside. Linux only.

Parallel Computing

DC - direct condense

(with Max Neunhöffer) This package provides a robust system for computing huge orbits under the operation of groups. This uses several server and client processes running on a (inhomgeneous) network of computers. This is based on an algorithm described in this article. Parts of the code which is written in C may be useful for other applications as well.

Teaching

OKUSON

(with Max Neunhöffer) A system for administrating exercise courses via the web. A special feature are individual exercise sheets with exercises which are automatically graded by the OKUSON system.

OKUSON is implemented in my favorite script language Python. It contains some independently useful modules, for example the web server which serves these pages.

Misc

memtst

A very simple program for testing memory hardware. We had several examples of computers with very rare bit errors (say once a week with long running jobs). While the standard tests with 'memtest/memtest86' did not detect memory errors, this program ran into errors every 1 to 30 minutes.

We use this for testing every new or repaired machine.

Just download the file via the link above. Hints on compilation are in the file header. Calling without argument gives usage information.

Last updated: Fri Jul 1 20:52:02 2022 (CET)