Gary J Nutt

Prototyping and simulating parallel, distributed computations

Abstract Designing parallel, distributed computations is a significant barrier to the effective use of contemporary equipment. One aspect of the barrier is the difficulty of partitioning a serial solution into a set of communicating computational subsets (e.g., processes) that can be distributed over heterogeneous processors in a distributed hardware environment. The Parallel Distributed computation Graph Model (ParaDiGM) and the VISual Assistant (VISA) have been designed to assist with the partitioning problem. The formal model is composed of two components: a micro model focuses on the functionality of the computation, while a consistent macro model explicitly represents the partition and the communication mechanisms. ParaDiGM encourages the designer to address functionality and partitioning in different submodels, maintaining a mapping between elements in the two submodels. ParaDiGM is formal, but has an intuitive visual presentation; its use is supported by the VISusal Assistant (VISA), a tool for designing, animating, simulating, and prototyping distributed computations. This note informally describes ParaDiGM and VISA, then illustrates how they can be used to assist with the design of parallel, distributed computations.