## nQueens -- World Record -- |

## nQueens n = 25 solved with ObjectWeb ProActive## 2,207,893,435,808,352 total solutions found## Two Quadrillion |

The OASIS
research
group, form INRIA
- University
of Nice Sophia Antipolis - CNRS
is pleased to announce the calculation of **N-Queen
for N=25**.

The
number of solutions is: **2207893435808352**

Thanks to the **ObjectWeb
ProActive library**,
the computation was achieved
in Peer-To-Peer
mode (P2P), just using the spare
CPU cycles of INRIA desktop
machines. As such , the computing platform was highly heterogeneous:
GNU/Linux, Windows, various JVMs, PII and PIV from 450 MHz to 3.4 GHz,
etc.

The total duration time was
slightly over **6 months**,
starting October 8th until June 11th, using the spare CPU cycles of
about
260 machines. The cumulated computing time was over **50
years**!

The nQueens problem consists to place n queens on a nxn chessboard with that no queens are enable to capture each others. More information about this problem are available here.

Start date: October 8th 2004

End time: June 11th 2005

Computation duration time = 4444h 54m 52s 854 i.e. 185 days 4
hours 54 minutes 52 seconds 854

Cumulated computation time = 464344h 35m 33s 553 i.e. 53 years 2 days 16 hours 35 minutes 33 seconds 553

This record is registered at: http://www.research.att.com/cgi-bin/access.cgi/as/njas/sequences/eisA.cgi?Anum=000170

Solutions for N = 24 :: 227514171973736

Total worker CPU time = 49271h 29m 57s 622 = 2053 days = 5 year and 6 month

Computation duration time = 413h 27m 57s 847 = 17 days

Feel free to send any suggestions to proactive@objectweb.org © 2001-2007 Inria Sophia Antipolis |