Object-oriented Modeling of Parallel PDE Solvers

This is a status report of a long-term research effort focusing on object-oriented modeling of parallel PDE solvers, based on finite difference methods on composite, structured grids. Two previous results of this effort are reviewed, the class libraries Cogito and Compose. Cogito is implemented in Fortran 90, with MPI for the message passing, and provides abstract data types for parallel composite-grid methods. Compose is in C++ and allows for fully object-oriented construction of PDE solvers by composition of objects. The object model behind Compose is described, and some research issues related to the refinement of the model are outlined. Finally, some recent results are presented, which are initial steps in addressing these issues.