In April, we have made a grid computing experiment in our University on the Langford problem.

We have used the middleware CONFIIT, developed by our team, to solve L(2,23). This is a fully distributed peer-to-peer environment designed to compute FIIT problems (applications with Finite number of Independent and Irregular Tasks). This Java written middleware aims at setting a logical ring organization for network's resources, such as PCs, workstations or parallel architectures. An overview of CONFIIT has been published in Olivier Flauzac, Michaël Krajecki, Jean Fugère: CONFIIT: A Middleware for Peer to Peer Computing. ICCSA 2003, International Conference, Montreal, Canada, May 18-21, 2003, Proceedings, Part III.

Reference no longer on line: Lecture Notes in Computer Science 2669 Springer 2003, pp. 69-78

To solve the Langford problem, we have implemented our parallel version of the algebraic method proposed by Mike Godfrey. Some optimizations have also been introduced in the method.

The computation have been made using 30 machines (9 PC Intel PIV and Xeon, AMD Athlon XP, 20 Sun Blade 100 and one parallel machine Sun FIRE 6800 with 24 processors). After 4 days, we obtained the following result: L(2,23)= 3 799 455 942 515 488

We are planing to publish this interesting result in a near future. First in a French national conference to be held in June (2004), GRIDUse and, second in an international conference during the summer.

Five people have been involved in this experiment: Olivier Flauzac (associate professor), Christophe Jaillet (PhD student), Michaël Krajecki (associate professor), Pierre-Paul Mérel (Post Doc) and Richard Tremblay (professor at the University of Quebec at Chicoutimi, Canada).

Best regards, Michaël Krajecki

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Michaël Krajecki
LERI Resycom - Université de Reims Champagne-Ardenne
Département de Mathématiques et Informatique
Moulin de la Housse - BP 1039
51687 Reims Cedex 2.