The Solver is a data-parallel program, written in High Performance Fortran. It is based on an ongoing effort to develop an HPF library for domain decomposition based sparse computations, which is in turn an adaptation of a Fortran 90 library developed by the Numerical Analysis Laboratory of Paris 11. A discussion of the techniques for handling unstructured computations in HPF is outside the scope of this paper; a survey can be found in [6] and examples for sparse matrix computations in [8] and [17].
The Domain Manager cannot be easily parallelized on a distributed memory machine, because it spends most of its execution time in searching complex data structures. In any case, its interface to the external world is assumed to be a sequential front-end.
Neither Fortran 90, nor HPF as a superset of Fortran 90, are object oriented languages. However, using their modularity and polymorphism features [13], makes rather easy to interface them with a truly object language.