Next: Introduction
Large scale transportation simulations on Beowulf Clusters
Nurhan Cetin1 and Kai Nagel2
Dept. of Computer Science, ETH Zürich, Switzerland
Postal: ETH Zentrum IFW B27.1, CH-8092 Zürich, Switzerland
Abstract:
If the individual entities in a system are used as the main components
of a traffic simulation, the simulation is called microscopic. When the
traffic density is high and the area covered is wide, the individual
elements of a microscopic simulation and also the simple rules such as
car following, lane changing, gap acceptance, can result in complex
behaviors. Such a large scale transportation simulation can consume more
time and more computing resources. A parallel computing approach to
such a big traffic system might be economical and efficient in terms of
money and consumed resources.
This paper describes a parallel approach to a microscopic traffic
simulation. The parallelization method is domain decomposition, which
means that each CPU of the parallel computer is responsible for a
different geographical area of the simulated region. We describe how
information between domains is exchanged, and how the transportation
network graph is partitioned. An adaptive scheme is used to optimize
load balancing.
We demonstrate how computing speeds of a parallel micro-simulations
can be systematically predicted once the scenario and the computer
architecture are known. This makes it possible, for example, to decide
if a certain study is feasible with a certain computing budget, and how
to invest that budget. The main ingredients of the prediction are
knowledge about the parallel implementation of the micro-simulation,
knowledge about the characteristics of the partitioning of the
transportation network graph, and knowledge about the interaction of
these quantities with the computer system. In particular, we investigate
the differences between switched and non-switched topologies, and the
effects of 10 Mbit, 100 Mbit, and Gbit Ethernet.
Keywords: Parallel computing, traffic simulation, transportation planning
Next: Introduction
Nurhan Cetin
2001-05-31