The BBN Butterfly used to simulate a molecular liquid

Abstract The problems involved in simulating a liquid on a MIMD and on a SIMD computer are analysed and compared, with specific reference to the BBN Butterfly and the ICL DAP respectively. A description of the Butterfly is given and the MIMD simulation on it is analysed in detail. Aspects of the system software of relevance to this simulation are presented and the programming practicalities are discussed. Timings are given for the molecular dynamics liquid SF6 simulation on the Butterfly, and a breakdown is given for the performance factors for this parallel computer. The rough estimate performance on this complete problem using a 44-processor machine was about 0.4 Mflops per processor.