AHPCRC Parallel Processing
Parallel Physically Based Object Oriented Simulation
Investigators
S. Sarathy and O. Olatidoye
Clark Atlanta University - Army HPC Research Center
Objective
Conventional approaches to modeling
complex physical systems are based on functional model paradigm.
These methods have proven to be very effective for isolated single use,
with a dedicated group of support personnel. However, in today's economic
climate, this is an unlikely scenario, instead
affordability becomes a key criterion in evaluating the effectiveness of a new
product. Modeling environments in particular are driven towards higher degrees
of reusability and reconfigurability. Object oriented paradigms have provided
the framework to achieve a high level of model and component reuse, together
with a component level reconfigurability. Physical Object Oriented Modeling
(P/OOM) is a subset of this broader approach, applied to a the domain of
vehicle dynamics. P/OOM provides a uniquely transparent and intuitive interface
to the model developer, enhancing a direct correspondence with the actual
system being modeled. P/OOM also provides to automated or semi-automated
methods to parallelize such models, by making use of the intrinsic parallel
nature of the model. This effort seeks to apply this technique to the
high fidelity modeling of
complex ground vehicles. These models will be parallelized for use in real
time simulation applications. This effort will focus on algorithms to improve
the automated/semi-automated task allocation methods used to develop the
parallel versions of these models.
Relevance
The modeling environment developed, can be used to develop
families of reusable and reconfigurable models. Incremental validation of
model variants together with the simplicity of the configuration management
schemes made possible by this approach will significantly lower the cost of
maintaining distinct, different and often incompatible, simulation models
of Army ground vehicles. In addition the parallel algorithms developed
here, will allow affordable simulators to be built around such a high
fidelity simulation, using commercial off the shelf parallel platforms.
Methodology
A subset of the object oriented modeling methodology customized
to vehicle dynamic physical phenomena (P/OOM) has been developed over the
last several years, applied to rotorcraft simulation models. This approach
will be now applied to the problem of ground vehicle dynamics.
The basic modeling environment is based on representing the physical form and
function of the actual vehicle, using a library of extremely abstracted and
encapsulated primitive component classes. This model is reduced to a task tree
and partitioned automatically using task set algorithms, for MIMD type
parallel architectures. Such an approach, though commonly adopted, is
inefficient giving rise to extreme sized task sets. Such extremes are usually
unacceptable even for shared memory machines. This is partly due to this
approach not accounting for synchronization/communication overheads. We are
developing a hybrid approach to enhance the efficiency and effectiveness of
these task pallcoation methods. Our approach includes the use of clustering
algorithms to improve load balancing, as well as allow the user to
embed parallel directives within the model to take advantage of topological
parallelisms inherent in the problem domain.
1. "Parallel physically based object oriented simulation models",
S. Sarathy and O. Olatidoye. Jan 1996,
SCS Western MultiConference, San Diego CA.
2. "Physical Object Based Simulation Modelling: Is it real ?",
S. Sarathy and P. van Gool. Oct/Nov 1995
CEAS-95 Making It REAL Simulation Symposium, Delft University, Netherlands
3. "Parallel Physical Object Based Simulation : Is it fast and cheap enough ?",
S. Sarathy and O. Olatidoye. Oct/Nov 1995,
CEAS-95 Making It REAL Simulation Symposium, Delft University, Netherlands