Multigrid Aircraft Computations Using the Oplus Parallel Library

This paper presents the OPlus library which is a exible library for distributed memory parallel computations on unstructured grids through the straightforward insertion of simple subroutine calls. It is based on an underlying abstraction involving sets, pointers (or mappings) between sets, and operations performed on sets. The key restriction enabling parallelisation is that operations on a particular set can be performed in any order. The set partitioning, computation of halo regions, and the exchange of halo data as required is performed automatically by the OPlus library after the user speciies the sets and pointers. A single source OPlus application code can be compiled for execution on either a parallel or a sequential machine, greatly easing maintainability of the code. The capabilities of the library are demonstrated by its use within a program for the calculation of inviscid ow over a complete aircraft using multigrid on a sequence of independent tetrahedral grids. Good computational eeciency is achieved on an 8-processor IBM SP1 and a 4-processor Silicon Graphics Power Challenge.