Finite Element Flow Computations on the Cray T3D,

This article addresses porting a code developed for the CM-5 to a Cray T3D. A second article addressing optimization on the Cray T3D will appear in the next issue. Driven by large speed and memory requirements of 3D computations, numerical formulations are increasingly adapted for use with a variety of massively parallel supercomputers. However, the style of programming varies from one architecture to another and porting codes across machines while maintaining efficiency becomes a major issue. Recently, the research group of Tayfun Tezduyar Professor of Aerospace Engineering and Mechanics at the AHPCRC ported the finite element flow solvers, which were originally developed for the CM-5, to the Cray T3D. Marek Behr, an Assistant Professor at the AHPCRC, performed the porting of the incompressible flow code from the CM-5 to the Cray T3D. Subsequently, this author extended the code to the compressible flow solver. Postdoctoral Research Associate, Andrew Johnson, and graduate student, Vinay Kalro, are also involved in parallel finite element computations on the Cray T3D. The Cray T3D, which is the first massively parallel supercomputer from Cray Research, was officially unveiled in late 1993. This scalable machine with 32 to 2048 processors has a peak performance from 4.8 to over 300 GFLOPS, with memory capacity of 512 Mbytes to 128 Gbytes. The Cray T3D takes advantage of a fast bidirectional 3D torus network which minimizes the inter- processor communication times and ensures short connection paths and high bisection bandwidth. The technical features of the Cray T3D, together with its remarkable stability in operation, makes this machine one of the state of the art systems for parallel computations.