Hi, to model this kind of constraint in Gecode you need to decompose it, i.e., you create an auxiliary matrix M' and post the constraints M'[i,j] = abs(M[i,j]), and then post the distinct constraints on M'.
Views, as suggested by Vijay, can't be used for modelling in Gecode, only for implementing your own propagator. Cheers, Guido > On 25 Oct 2014, at 8:25 pm, Bouchene Sabrina <genius_linda1...@yahoo.fr> > wrote: > > Hi, > > I want to use "alldifferent" constraint or a "distinct" constraint but in my > case, i have a matrix M and i would that the elements (values) of the row of > a matrix be different, but the variables of the row can have positive and > negative values, so i would have a constraint that for example: > > if row = 1 then the absolute values of M[1, j] could be all different, that > means, if i have M[1,1]=(-3), i should not get M[1,j] =(+3) for j =1 to n. so > in the same row or in the same column if i have (val) i must not have (-val) > or if i have (-val) i mast not have (val). > > alldifferent (|M[i, j]|). > > My question is how to write this constraint in Gecode ?. > I hope my question was clear. > > Best regards. Sabrina > > _______________________________________________ > Gecode users mailing list > users@gecode.org > https://www.gecode.org/mailman/listinfo/gecode-users
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