University of Bielefeld,
Institute for the Simulation of Complex Systems
Emphases of Research
Simulation methods for the examination of complex systems are used today
in different areas of scientific research. On varied scales complex systems
are difficult to describe with the usual analytical methods because of
their complicated interaction. The questions extend from the meanwhile
classic problems of dynamics and phase structure of many body systems to
nowadays relevant problems like the critical behaviour of fluctuating membranes,
spin glasses, chaotic and self-organized systems or neuronal nets. The
arisal of these new questions from new subject areas is closely linked
to the rapid progress in computer technology. Problems that formerly were
regarded as unsolvable can now be numerically investigated.
The classical simulation techniques (Monte-Carlo algorithms, molecular
dynamics, finite-element method) are found today in many commercial program
packages and are used industrially (aero- and hydrodynamic, meteorology,
earth-quake research, among others). The further development of these methods
strongly profits from developments in related natural science disciplines
(physics, chemistry, mathematics) and from completely new formulated questions
in other disciplines such as biology, linguistics of sociology. Also -
based on the steady increase in performance of modern supercomputers -
new questions arise on numerical investigations that were regarded as unsolvable.
At the same time the new, hardly standardized structures of modern supercomputers
(massive parallel computers) often require to rethink the further development
of simulation techniques - new algorithms are feasible on massive parallel
computers; the usual vectorial algorithms are no longer efficient. This
strongly requires the cooperation of the users of supercomputers and their
collaboration in software development for new computer architectures. Only
this will ensure an optimal use of the latest development on higher level
computer technology.
ISKOS offers the possibility for investigating complex questions with
the aid of supercomputers and to build up contacts with related disciplines
that analyse similar problems. The emphasis of research at ISKOS is currently
the simulation of dynamics and thermo-dynamics of strong interactive many
body systems that is investigated by the computer-simulation-group of the
physics department.
Summary of Previous Activities
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ISKOS is responsible for the QUADRICS computers which have a combined computing
capacity of more than 25 Gflops. One half of this equipment was originally
made available to the resarch project ``Dynamical Fermions'' by DFG. Based
on the affirmation of ISKOS to further use these computers they remained
in Bielefeld after termination of the research project in summer 1997.
Groups from other universities, e.g. Leipzig, Münster and Wuppertal,
still carry out projects. Moreover it was extremely important for the training
of students and graduate students to keep the computers in Bielefeld. Among
German universities it is one of the largest computers used for research.
A computer of the new generation with a nominal capacity of 84 Gflops
was applied for by ISKOS and after positive assessment was approved in
March.
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Two so-called PC-Farms were concipated and put into operation by members
of ISKOS, one in the computer centre of the university and the other at
the Department of Physics. These PC-Farms are extraordinarily efficient
compared to their costs. They are especially suitable for the simulation
of disordered complex systems that cannot be fitted to parallel computers
but are very important in biology and physics.
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Each year an introductory
interdisciplinary block practical training is carried out which is
especially well accepted by physics and natural science informatics students.
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ISKOS offers its competence to all those groups in university that want
to work on intensive computational problems with the aid of parallel computers,
particularly of the Quadrics type.
A special ISKOS-room with work stations and terminals is available
in UHG, E5-124. This is also where ISKOS holds its computer practical training.
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Colloquia are regularly held by members of various faculties of the university
or by invited guests from other universities or research centers in Germany
as well as from abroad.
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An important part of the activities is the collaboration with other similar
institutions, particularly with the Paderborn
Center for Parallel Computing, PC ,
in Paderborn, the Institute for Applied Informatics (IAI) in Wuppertal
and the Parallel
Computer Center of DESY-Zeuthen (NIC-Zeuthen). There are also close
contacts with the INFN in Italy where the Quadrics computers were designed
as well as with QSW company which produced the computers. Within a cooperative
agreement between DESY, QSW and the Universities of Bielefeld and Wuppertal
(ACOMO) a prototype of the new computer generation will be made available
to ISKOS. For the next four to five years there are also interests in further
collaboration in development and use of specialized systems with very large
computing capacities up to 30 Gflops.
So far the collaboration has been formalized in the ACOMO-agreement
and the Research Cooperation Bielefeld-Paderborn.
A futher agreement Bielefeld-Paderborn-Wuppertal with special emphasis
on the education of students on the most modern (latest) parallel high
performance computers is in preparation. This collaboration is especially
relevant as new computers of individual design but all of the latest generation
of high performance computers are expected to be installed in all three
institutes during this year.
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ISKOS and the Paderborn Center for Parallel Computing PC ,
Paderborn in Paderborn have been very productive in their collaboration.
This has lead to the joint ZiF project Multi-Scale Phenomena: The Simulation
of Complex Systems on Massively Parallel Computers in the years 1996
to 1998. Many internationally recognized scientists on the subject of simulation
of complex systems were invited for shorter or longer periods. Two workshops
also took place during this project.
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Furthermore the university's computer center operates a high speed data
link between Bielefeld and Paderborn which makes new forms of collaboration
(Meta-Computing) possible between ISKOS and PC .
ISKOS as well as PC have contributed to
the realization of this link. The link was opened on June 22, 1998, and
enables us to connect the two computers, which are of different types and
therefore complementary. Therefore, without any delay parts of a problem
can be dealt with on one computer and other parts on the other. This type
of meta-computing is a relevant and promising possibility for the future.
It is very fortunate that this pioneering system could be realized in our
region.
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A collaboration exists with several institutes of similar type in USA and
Japan. Close contacts exist particularly with one of the most prominent
institutes, the Institute
of Computational Physics, Tsukuba, Japan. This institute operates
a supercomputer of 600 Gigaflops, one of the largest in the world.
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ISKOS participates in planning an European Computer Center for the simulation
of matter in extreme conditions. In view of this ISKOS organized a meeting
in 1998 in Bielefeld. A second meeting took place in Trento in March 1999.
It is quite possible that Bielefeld will be the location for this computer
center due to the here existing experience and competence.
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ISKOS manages a data bank for the EU-Network
Phase Transition in Hot Matter.
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The simulation of complex systems is a very important factor also for the
new research focus Biosphysics that is to be implemented at the
Department of Physics and it should benefit from the competence and computers
of ISKOS.
Particularly promising should be the meta-computing project with the University
of Paderborn, especially when the new computers have been installed. Metacomputing
enables research to work on advanced grades of problems.
A possible European Computer Center in Bielefeld as well as joint lectures
with Wuppertal and Paderborn on high performance computers will put new
demand on ISKOS.
Natural science students that can also accumulate experience on modern
high performance computers should have excellent possibilities on the job
market.
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Gudrun Eickmeyer
Ines Wetzorke
Last Update: 22.2.2000