Notes on merging networks

Several new results which contribute to the understanding of parallel merging networks are presented. First, a simple new explanation of the operation of Batcher's merging networks is offered. This view leads to the derivation of a modified version of Batcher's odd-even (m, n) network which has delay time [log(m + n)]. This is the same delay time as Batcher's bitonic (m, n) network, but it is achieved with substantially fewer comparators. Second, a correspondence is demonstrated between the number of comparators (and the delay time) for such networks and certain properties of binary number systems which have recently been extensively studied. Third, the (log(m + n)] delay time is shown to be optimal for a non-degenerate range of values of m and n.