Werkzeugunterstuetzte Parallelisierung von Finite-Element Anwendungen (PARFEM) Abschlussbericht

Goal of the PARFEM project was the development of software tools and methods to support the efficient treatment of large sparse matrices on parallel computers. Also new algorithms for the solution of such systems should be investigated. Portability of all components was an important aspect. Finally, the algorithms and methods should be integrated in the well-known FE software package PERMAS. The parallelization concept for PERMAS is based on the exploitation of task parallelism and not on the usual mesh partitioning (or domain decomposition) technique. The solution of the sparse system leads to the execution on many tasks which operate on independent data and which can be executed in parallel. A task graph controls the data dependency. A scheduler maps those tasks to processors and tries to achieve load balance. As an alternative to the standard direct Cholesky solver parallel preconditioned cg-solvers and parallel multifrontal solvers were implemented and investigated: - Several variants of preconditioners were tested as well as different storage schemes. The optimal variants showed very good speed-up results and the execution time was shorter than the time of the standard direct solver for a large number of processors. The integration into the PERMAS code, however, lead to some loss of scalability. - A parallel multifrontal solver was integrated and parallelized using the tools developed in the project. Speedup figures on an IBM SP2 system were satisfactory. The PARFEM project was very important for the development of the PERMAS code. The tools in PARFEM made it possible to maintain one version of the code for sequential and parallel platforms. Users can use the parallel code without additional training since the user interface was not changed at all. Since portability was very important the project used PARMACS and later MPI as portability platform. The parallel approach could even be executed on workstation clusters although, due to weak communication performance, not very efficiently. (orig.)SIGLEAvailable from TIB Hannover: F98B607+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman