N -Graphs: A Topology for Parallel Divide-and-Conquer on Transputer Networks

A parallel implementation of a divide-and-conquer template (skeleton) is derived systematically from its functional speciication. The implementation makes use of a new processor topology for divide-and-conquer, called N-graph, which suits transputer networks well: there are not more than 4 links per processor, overlapping of computations and communication within a processor is exploited, the processor network is of an arbitrary xed size, the load is balanced and all communications between processors are local. A parallel mergesort algorithm is used to illustrate the derivation process and the distributed parallel target program. Experimental results on a 64-node transputer network are reported.