Communication Complexity for Parallel Divide-and-Conquer

I-Chen Wu, H. T. Kung

Abstract: The relationship between parallel computation cost and communication cost for performing divide-and-conquer (D&C) computations on a parallel system of p processors is studied. The parallel computation cost is the maximal number of the D&C nodes that any processor in the parallel system may expand, whereas the communication cost is the total number of cross nodes (nodes generated by one processor but expanded by another processor). A scheduling algorithm is proposed, and lower bounds on the communication cost are derived. The proposed scheduling algorithm is optimal with respect to the communication cost, since the parallel computation cost of the algorithm is near optimal.<