TY - GEN A1 - Wolf, Thomas A1 - Neun, Winfried T1 - About a Computer Algebra based online Mathtest N2 - The article describes the online mathematics test {\tt http://lie.math.brocku.ca/mathtest}, its typical applications and experiences gathered. T3 - ZIB-Report - 08-14 KW - accessment of mathematical skills KW - computer algebra KW - online Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-10688 SN - 1438-0064 ER - TY - GEN A1 - Neun, Winfried A1 - Sturm, Thomas A1 - Vigerske, Stefan T1 - Supporting Global Numerical Optimization of Rational Functions by Generic Symbolic Convexity Tests N2 - Convexity is an important property in nonlinear optimization since it allows to apply efficient local methods for finding global solutions. We propose to apply symbolic methods to prove or disprove convexity of rational functions over a polyhedral domain. Our algorithms reduce convexity questions to real quantifier elimination problems. Our methods are implemented and publicly available in the open source computer algebra system REDUCE. Our long term goal is to integrate REDUCE as a workhorse'' for symbolic computations into a numerical solver. T3 - ZIB-Report - 10-01 KW - Nonlinear Global Optimization KW - Hybrid Symbolic-Numeric Computation KW - Convex Functions KW - Real Quantifier Elimination Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11644 SN - 1438-0064 ER - TY - JOUR A1 - Chrapary, Hagen A1 - Dalitz, Wolfgang A1 - Neun, Winfried A1 - Sperber, Wolfram T1 - Design, Concepts, and State of the Art of the swMATH Service JF - Mathematics in Computer Science N2 - In this paper, the concepts and design for an efficient information service for mathematical software and further mathematical research data are presented. The publication-based approach and the web-based approach are the main building blocks of the service and will be discussed. Heuristic methods are used for identification, extraction, and ranking of information about software and other mathematical research data. The methods provide not only information about the research data but also link software and mathematical research data to the scientific context. Y1 - 2017 U6 - https://doi.org/10.1007/s11786-017-0305-5 VL - 11 IS - 3-4 SP - 469 EP - 481 ER - TY - JOUR A1 - Neun, Winfried A1 - Sturm, Thomas A1 - Vigerske, Stefan T1 - Supporting Global Numerical Optimization of Rational Functions by Generic Symbolic Convexity Tests JF - Computer Algebra in Scientific Computing Y1 - 2010 SN - 978-3-642-15273-3 VL - LNCS 6244 SP - 205 EP - 219 ER - TY - GEN A1 - Melenk, Herbert A1 - Neun, Winfried T1 - Parallel Polynomial Operations in the Buchberger Algorithm. N2 - The Buchberger algorithm is a basic tool for the solution of systems of polynomial equations in an environment of computer algebra applications. A model for overlapped processing of different steps of the algorithm is presented, which uses the data structure of the polynomials (distributive representation) for synchronization. The model can be applied for multi processors with fast access to shared data. It is tested with Cray X-MP multi processors based on a parallel version of Portable Standard Lisp (PSL 3.4). T3 - ZIB-Report - SC-88-04 Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-125 ER - TY - GEN A1 - Melenk, Herbert A1 - Möller, H. Michael A1 - Neun, Winfried T1 - Symbolic Solution of Large Stationary Chemical Kinetics Problems. N2 - The paper presents a new application of computer algebra to the treatment of steady states of reaction systems. The method is based on the Buchberger algorithm. This algorithm was modified such that it can exploit the special structure of the equations derived from reaction systems, so even large systems can be handled. In contrast to numerical approximation techniques, the algebraic solution gives a complete and definite overview of the solution space and it is even applicable when parameter values are unknown or undetermined. The algorithm, its adaptation to the problem class and its application to selected examples are presented. T3 - ZIB-Report - SC-88-07 Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-157 ER - TY - GEN A1 - Melenk, Herbert A1 - Neun, Winfried T1 - Portable Standard LISP for CRAY X-MP Computers. N2 - Portable Standard LISP (PSL) is a portable implementation of the programming language LISP constructed at the University of Utah. The version 3.4 of PSL was implemented for CRAY X-MP computers by Konrad-Zuse-Zentrum Berlin; this implementation is based to an important part on the earlier implementation of PSL 3.2 at the University of Utah, Los Alamos National Laboratories and CRAY Research Inc. at Mendota Heights. During the work on implementing PSL the language LISP was investigated for areas which can be supported by vector hardware. One area was found in the COMMON LISP sequence functions and some typical application areas of LISP programming can be improved by vector processing too. A model for the implementation of vector instructions in LISP was developed. For arithmetic an experimental vectorizing extent of the PSL compiler was constructed. With this means full vector hardware capacity can become available for LISP applications. T3 - ZIB-Report - SC-86-02 Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-28 ER - TY - GEN A1 - Anderson, J. A1 - Galway, W. A1 - Kessler, R. A1 - Melenk, Herbert A1 - Neun, Winfried T1 - The Implementation and Optimization of Portable Standard LISP for the CRAY. N2 - Portable Standard LISP (PSL), a dialect of LISP developed at the University of Utah, has been implemented and optimized for the CRAY 1 and CRAY X-MP supercomputers. This version uses a new implementation technique that permits a step-by-step development of the PSL kernel. The initial CRAY version was acceptable, although the execution speed of the PSL was not as fast as had been anticipated. CRAY-specific optimizations were undertaken that in some cases provided a ten-fold speed improvement, resulting in a fast LISP implementation. T3 - ZIB-Report - SC-87-01 Y1 - 1987 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-31 ER - TY - GEN A1 - Neun, Winfried A1 - Melenk, Herbert T1 - Implementation of the LISP-Arbitrary Precision Arithmetic for a Vector Processor. N2 - Portable Standard LISP (PSL, Version 3.4) and REDUCE 3 were implemented for CRAY1 and Cray X- MP computers at the Konrad-Zuse-Zentrum Berlin in 1986. As an special aspect of the implementation of PSL, an interface to the vector hardware of CRAY processors was defined. With that interface and mostly driven by the needs of REDUCE applications (e.g. extensive calculations of Gröbner bases), the arbitrary precision integer arithmetic of PSL was rebuild using full power of the vector hardware. A modular arithmetic using vector hardware was also constructed. T3 - ZIB-Report - SC-88-01 Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-93 ER - TY - GEN A1 - Melenk, Herbert A1 - Möller, H. Michael A1 - Neun, Winfried T1 - On Gröbner Bases Computation on a Supercomputer Using REDUCE. N2 - Gröbner bases are the main tool for solving systems of algebraic equations and some other problems in connection with polynomial ideals using Computer Algebra Systems. The procedure for the computation of Gröbner bases in REDUCE 3.3 has been modified in order to solve more complicated algebraic systems of equations by some general improvements and by some tools based on the specific resources of the CRAY X-MP. We present this modification and illustrate it by examples. T3 - ZIB-Report - SC-88-02 Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-107 ER -