db_connect: Could not connect to paper db at "wotug@dragon.kent.ac.uk"
db_connect: Could not connect to paper db at "wotug@dragon.kent.ac.uk"
%T A Comparison of Parallel Implementations of Flux Corrected Transport Codes db_connect: Could not connect to paper db at "wotug@dragon.kent.ac.uk"
%A Jing\-ming Jong, G. S. Stiles db_connect: Could not connect to paper db at "wotug@dragon.kent.ac.uk"
%E J. Wexler %B OUG\-11: Developing Transputer Applications %X We present the results of comparing implementations of the Flux Corrected Transport (FCT) method on transputers and several other parallel and sequential machines. FCT is a finite difference scheme used to solve fluid dynamics problem which may involve steep gradients or shocks; it has proven useful for both one\- and two\-dimensional problems in plasma physics, atmospheric sciences, and detonation studies. The method vectorizes very well and hence runs quickly on supercomputers. Since the calculations at each point involve only a small number of neighbors, the method can also be efficiently implemented on multi\-processor systems. We have run one\- and two\-dimensional problems on Transputers and several other systems, including a VAX 8650, a SUN 4/280, a four\-processor Ardent Titan, an eight\-processor Alliant FX/8, and a four\-processor Silicon Graphics 240GTX. We shall also compare our results to those obtained by Gustafson (1988) on the NCube/ten.If, in the 1\-d problem, we consider the speed of a single T800 to be 1.0, the SUN 4/280 ranks at 3.8, the VAX 8650 at 4.0, 8 TSOOs at 7.9, the Silicon Graphics 240GTX at 27.0, the FX/8 at 56.9, and the Titan at 64.4. On the 1\-d problem, again taking one T800 to have a speed of 1.0, the SUN comes in at 3.6, 16 NCube nodes at 4.0, the 8650 at 4.3, 8 TSOOs at 7.7, the Titan at 65.3, and the FX/8 at 101.4. The transputer ranks highest if we calculate the cost\-effectiveness of the various systems by dividing the relative speed by the approximate cost. If we assume the 8 TSOOs have a cost\-effectiveness of 1.0 on the 1\-d problem, the Titan is second at 0.52, followed by the 240GTX at 0.17, the FX/8 at 0.094, the SUN at 0.081, and the VAX at 0.021.