Carleton University
Technical Report TR-231
December 1993

Optimal Elections in Labeled Hypercubes

Paola Flocchini & Bernard Mans

Abstract

We study the message complexity of the Election problem in Hypercube net­works, when the processors have a “Sense of Direction”, i.e. the capability to distinguish between adjacent communication links according to some globally con­sistent scheme.
We present an original 0(N) messages algorithm which uses the natural dimen­sional labeling of the communication links; to date, the best existing bound was O(N log N) messages. This result answers a long-standing open problem posed by the 0(N) messages bound for chordal rings [1].
We also consider the Election problem for Hypercube with another common labeling which is distance-based. We prove that, in this case the problem becomes drastically simplified and we present a 0(N) messages solution. Finally, we study the communication cost to change one orientation labeling to the other and prove that O(N) messages suffice.

TR-231.pdf