A Very Fast (Linear Time) Distributed Algorithm, on General Graphs, for the Minimum-Weight Spanning Tree

International audienceThis paper develops linear time distributed algorithm, on general graphs, for the minimum spanning tree, in asynchronous communication network. We concentrated our efforts on the improvement of the execution time this is why our algorithm is faster than all previous linear algorithms. Our algorithm propose a solution for computing the MST in time $n/2$ with $O(n^2)$ messages (where $n=|V|$ for a graph $G=(V,E)$). The total number of messages in the worst case is slightly higher than the others algorithms, but in practice is often better

Critical Path Scheduling Parallel Programs on an Unbounded Number of Processors

International audienceIn this paper we present an efficient algorithm for compile-time scheduling and clustering of parallel programs onto parallel processing systems with distributed memory, which is called The Dynamic Critical Path Scheduling DCPS. The DCPS is superior to several other algorithms from the literature in terms of computational complexity, processors consumption and solution quality. DCPS has a time complexity of O (e + v\log v), as opposed to DSC algorithm O((e + v)\log v) which is the best known algorithm. Experimental results demonstrate the superiority of DCPS over the DSC algorithm

Tirer les ficelles de l'architecture TCP/IP avec Marionnet

National audienceMarionnet est un logiciel permettant de définir, configurer, exécuter et contrôler un réseau virtuel constitué d'ordinateurs utilisant le système d'exploitation GNU/Linux, de concentrateurs, de commutateurs, et de routeurs. Avec Marionnet, il est possible d'expérimenter la mise en oeuvre complète d'un réseau local : le projet, le câblage, le lancement, la configuration, l'administration, l'étude de protocoles et le test de services ou d'applications. Il permet de pratiquer, analyser et contrôler les différentes couches réseaux qui constituent l'architecture DoD (TCP/IP) : depuis le niveau physique jusqu'au niveau application. Adopté dans une structure universitaire, Marionnet permet de réduire l'utilisation des vraies salles de " TP réseau ", constituées d'équipements souvent onéreux et difficiles à maintenir en parfait état de marche. Il permet aussi aux étudiants de travailler à distance ou dans les salles informatiques ordinaires en accès libre

A Distributed Algorithm for the Minimum Diameter Spanning Tree Problem

International audienceWe present a new algorithm, which solves the problem of distributively finding a minimum diameter spanning tree of any (non-negatively) real-weighted graph G=(V,E,\omega). As an intermediate step, we use a new, fast, linear-time all-pairs shortest paths distributed algorithm to find an absolute center of G. The resulting distributed algorithm is asynchronous, it works for named asynchronous arbitrary networks and achieves O(|V|) time complexity and O(|V| |E|) message complexity

Parallelization of Littlewood-Richardson Coefficients Computation and its Integration into the BonjourGrid Meta-Desktop Grid Middleware

International audienceThe aim of this paper is to show how to parallelize a compute intensive application in mathematics (Group Theory) for an institutional Desktop Grid platform coordinated by a meta-grid middleware named BonjourGrid. The paper is twofold: first of all, it shows how to parallelize a sequential program for a multicore CPU which participates in the computation and second it demonstrates the effort for launching multiple instances of the solutions for the mathematical problem with the BonjourGrid middleware. BonjourGrid is a fully decentralized Desktop Grid middleware. The main results of the paper are: a) an efficient multi-threaded version of a sequential program to compute Littlewood- Richardson coefficients, namely the Multi-LR program and b) a proof of concept, centered around the user needs, for the BonjourGrid middleware dedicated to coordinate multiple instances of programsfor Desktop Grids and with the help of Multi-LR. In this paper, the scientific work consists in starting from a model for the solution of a compute intensive problem in mathematics, to incorporate the concrete model into a middleware and running it on commodity PCs platform managed by an innovative meta Desktop Grid middleware

Un Algorithme distribue d'electIon non pre-determinee et d'arbre couvrant

Projet PARADISRésumé disponible dans le fichier PD

Construction repartie d'arbre couvrant de diametre minimum

Dans cet article, nous proposons une solution au probleme de la construction d'un arbre couvrant de diametre minimum sur un graphe value non-oriente. Ce probleme est pose dans un contexte nouveau, celui de l'algorithmique repartie et notre solution, presentee sous forme d'algorithme distribue, a une complexite de 0(mn2log2(n+W)) en nombre de bits echanges (ou n est le nombre de noeuds, m le nombre d'aretes et W le poids maximum d'une arete). Notre approche est validee par des resultats experimentaux qui confirment que notre algorithme, sur differents reseaux, realise la construction, ou la reconstruction apres panne d'une structure de controle efficace