The most efficient known algorithm for solving n-queens is the fairly
obvious backtracking one, where you place one queen at a time, giving
up and backtracking when you fail. This is *not* a brute-force search
-- brute force would be explicitly checking each possible board
position with all eight queens on the board at once, which is a much
bigger search.
Here's a good paper about the backtracking solution:
http://penguin.ewu.edu/~trolfe/SCCS-95/SCCS-95.html
Now, as far as an implementation in Jess: Michel Futtersack's CCP page
has a couple of different solutions in the CLIPS (Jess) language. See http://www.droit.univ-paris5.fr/futtersack/english/research/CCP/index.html
. There's one simple solution for 5-queens in a single rule. But his
general constraint-satisfaction paradigm leads to an excellent
solution, linked from that page. The code needs only small changes to
work with Jess.
On May 11, 2008, at 5:15 PM, Senlin Liang wrote:
Dear all,
I am trying to solve the N-Queens problem using Jess. Is there a way
to use rules to make a efficient program, or I have to use functions
to do the brute force search?
I am trying to compare several systems to see which one is good at
this N-Queens problem.
Thanks,
Senlin
---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences Phone: (925) 294-2154
Sandia National Labs FAX: (925) 294-2234
PO Box 969, MS 9012 [EMAIL PROTECTED]
Livermore, CA 94550 http://www.jessrules.com
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