Parallel Simulation of Orography Influence on Large-Scale Atmosphere Motion on APEmille

摘要

The experience described in this paper relates to the implementation on the parallel computer APEmille of a model for large-scale atmosphere motion,originally developed in Fortran for a conventional architecture.The most critical aspects of this work are described:the mapping of a bidi-mensional problem on the tridimensional thoroidal architecture of the parallel machine,the choice of a data distribution strategy that minimizes the internode communication needs, the definition of an algorithm for internode communication that minimizes communication costs by performing only first neighbour communications,and the implementation of machine dependant optimizations that allowed to exploit the pipelined architecture of the APEmille processing node and the large register file.An analysis of the performances is reported,compared to both the APEmille peak performance and to the performance on other conventional sequential ar chitectures.Finally,a comparison with the original physical results is presented.