Low Randomness Rumor Spreading via Hashing

George Giakkoupis (1) , Thomas Sauerwald (2) , He Sun , Philipp Woelfel (3)

1 LIAFA - Laboratoire d'informatique Algorithmique : Fondements et Applications
2 ICSI - International Computer Science Institute [Berkeley]
3 CPSC - Department of Computer Science [Calgary]

We consider the classical rumor spreading problem, where a piece of information must be disseminated from a single node to all n nodes of a given network. We devise two simple push-based protocols, in which nodes choose the neighbor they send the information to in each round using pairwise independent hash functions, or a pseudo-random generator, respectively. For several well-studied topologies our algorithms use exponentially fewer random bits than previous protocols. For example, in complete graphs, expanders, and random graphs only a polylogarithmic number of random bits are needed in total to spread the rumor in O(log n) rounds with high probability. Previous explicit algorithms require Omega(n) random bits to achieve the same round complexity. For complete graphs, the amount of randomness used by our hashing-based algorithm is within an O(log n)-factor of the theoretical minimum determined by [Giakkoupis and Woelfel, 2011].

Mots clés: Parallel and Distributed Computing; Randomness; Rumor Spreading

Domaines: Complexité [cs.CC]; Algorithme et structure de données [cs.DS]

George Giakkoupis, Thomas Sauerwald, He Sun, Philipp Woelfel. Low Randomness Rumor Spreading via Hashing. STACS'12 (29th Symposium on Theoretical Aspects of Computer Science), Feb 2012, Paris, France. pp.314-325. ⟨hal-00678212⟩