Abstract:
This paper details the PELLPACK system, a comprehensive Problem Solving Environment (PSE) designed for modeling physical objects using Partial Differential Equations (PDEs). With a codebase exceeding one million lines, PELLPACK's flexible, open-ended software architecture integrates multiple PDE-solving systems and methods, providing broad coverage for various problem types, including elliptic, parabolic, and some hyperbolic problems. The system's layered architecture includes an interactive graphical interface for problem specification, a high-level PDE language for textual input, and a preprocessor that generates Fortran control programs. PELLPACK incorporates parallel reuse methodologies based on the decomposition of discrete geometric data to efficiently map sparse PDE computations to parallel machines. It supports multiple parallel execution models, such as hosted, hostless, Mplus, and Dplus, and includes tools for mesh generation, domain decomposition, and visualization. The system also integrates "foreign" solvers like VECFEM and NSC2KE, and supports the reuse of sequential "legacy" PDE software in a parallel context. An expert system component, PYTHIA, assists users in selecting the most efficient algorithms and parameters by analyzing performance data from similar problems. PELLPACK is available as a Web server, WebPELLPACK, to provide public access to its capabilities and facilitate remote computation. This extensive system illustrates a new paradigm in scientific software, moving beyond simple libraries to a fully integrated environment that simplifies complex computational tasks for scientists and engineers.
