The main contribution of this work is to present elegant broadcast-efficientalgorithms for permutation routing, ranking, and sorting n items on the Broadcast Communication Model (BCM, for short) endowed with p processors and k communication channels. We begin by presenting an optimal off-line routing algorithm using n k broadcastrounds for any k, p, and n. We then go on to develop an on-line routing algorithm that takes 2n k + k , 1 broadcast rounds on a p-processor, k-channel BCM, whenever k pp 2 . Using this routing algorithm, we develop a ranking algorithm that takes only 3n k + o n k broadcast rounds, as well as a sorting algorithm that takes 4n k +o n k broadcastrounds on a p-processor, k-channel BCM, provided that k pp 2 and p 2 on. Our algorithms offer a significant improvement over the state of the art.
Koji Nakano, Stephan Olariu, James L. Schwing