Efficient composition and automatic initialization of arbitrary structured PVM programs

There are significant programming and methodological problems when developing PVM programs, the process communication structure of which does not form trees but arbitrary graphs. We present a design methodology, called Ensemble, and the appropriate PVM techniques and tools for the efficient composition of arbitrarily structured PVM programs. In Ensemble PVM programs are described by annotated Process Communication Graphs (PCGs) and the sequential program components are designed with open communication interfaces. The annotated PCGs are interpreted by a universal PVM program Loader which spawns processes and sets values to their communication interfaces, thus establishing the program communication structure. The program components are reusable without any modification in other PVM programs. Annotated PCGs are produced from PVM program scripts. The methodology may be applied to any message passing environment by developing specific annotations of the PCG, reusable program components and the program loader.