Research Associates: A.C. Catlin, M. Gaitatzes, P. Papachiou, K.-Y.
Wang, and S. Weerawarana
The problem solving environment (PSE) Parallel ELLPACK
(PELLPACK) is for modeling physical objects described by
partial differential equations (PDEs). The scope of this PSE is
broad as PELLPACK incorporates many PDE solving systems and some of
these, in turn, include several specific PDE solving methods. Its
coverage for 1-D, 2-D and 3-D elliptic or parabolic problems is
quite broad, and it handles some hyperbolic problems. Since a PSE
should provide complete support for the problem solving process,
PELLPACK also contains a large amount of code to support graphical
user interfaces, analytic tools, user help, domain or data
selection, visualization, and various other tasks. Its total size
is well over 1 million lines of code. Its "open-ended" software
architecture consists of five software layers. The top layer is an
interactive graphical interface for specifying the PDE model and
its solution framework. This interface saves the results of the
user specification in the form of a very high level PDE language
which is the second layer of interface to the PELLPACK system. This
language also allows a user to specify the PDE problem and its
solution framework textually in a "natural" form. In the third
layer, the PELLPACK language preprocessor generates a Fortran
control program with the interfaces, calls to specified components
and libraries of the PDE solution framework, and functions defining
the PDE problem. The fourth layer is an execution environment where
the virtual parallel system is defined, where the execution mode,
file system, and hardware resources are selected, and where the
compilation, loading, and execution are controlled. Finally, the
bottom layer consists of several PDE system libraries and their
interfaces to the PELLPACK system. The system employs several
parallel reuse methodologies based on the decomposition of discrete
geometric data to map sparse PDE computations to parallel machines.
An instance of the system is available as a Web server
(Web //ELLPACK) for public use. The ACM Trans. Math. Software
paper
describing PELLPACK and a
tour
of its facilities are available on the web.