From: Bogdan Tanasa <g-bogta_at_ida.liu.se>

Date: Thu, 26 Jan 2012 17:29:47 +0100

Date: Thu, 26 Jan 2012 17:29:47 +0100

Hi, A solution is an instantiation of that matrix. Any permutation of the columns of that matrix represents the same solution. How can I avoid this situation in CLP? Thanks, Bogdan. -----Original Message----- From: Marco Gavanelli [mailto:marco.gavanelli_at_unife.it] Sent: 26 ianuarie 2012 16:13 To: eclipse-clp-users_at_lists.sourceforge.net Subject: Re: [eclipse-clp-users] Symmetry On 26/01/12 15:09, Bogdan Tanasa wrote: > I have a problem for which the boolean optimization variables are of the > following form (a matrix): > > > > x_11, x_12, .., x_1n > > x_21, x_22, .., x_2n > > . > > x_n1, x_n2, .., x_nn > > > > In my case a solution of the form > > 0 1 0 1 > > 0 0 0 1 > > 0 1 0 1 > > Is identical with > > 1 0 1 0 > > 0 0 1 0 > > 1 0 1 0 > >> From the cost function point of view. > > > > Can you please tell me how to ignore exploring the symmetrical solutions of > this form ? To avoid this symmetry (this very symmetry), you can add the constraint: X_11 #\= 0 or X_12 #\= 1 or X_13 #\= 0 or X_14 #\= 1 or X_21 #\= 0 or X_22 #\= 0 or X_23 #\= 0 or X_24 #\= 1 or X_31 #\= 0 or X_32 #\= 1 or X_33 #\= 0 or X_34 #\= 1 If you want something more general, you might want to explain in more detail why these two solutions are symmetric in your problem. Best, Marco -- Marco Gavanelli, Ph.D. in Computer Science Dept of Engineering University of Ferrara Tel/Fax +39-0532-97-4833 http://www.ing.unife.it/docenti/MarcoGavanelli/ ---------------------------------------------------------------------------- -- Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ ECLiPSe-CLP-Users mailing list ECLiPSe-CLP-Users_at_lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/eclipse-clp-usersReceived on Thu Jan 26 2012 - 16:30:00 CET

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