[gecode-users] Modelling Conditions on Latin Squares

[Christian Drescher]

Thank you for the help!

Also, the element constraint expects Matrix<IntVarArgs>, not
Matrix<IntVarArray>.

Best,
Christian


On Fri, 2009-10-30 at 09:06 +0100, Christian Schulte wrote:
> I guess the problem is that element over matrices expects variables as
> arguments and not integers. So instead of:
> 	element(home, mat, mat(i,j), mat(j,i), i)
> You have to create an integer variable that is equal to i and use that as
> last argument, such as:
> 	element(home, mat, mat(i,j), mat(j,i), IntVar(home,i,i))
> 
> Cheers
> Christian
> 
> --
> Christian Schulte, www.ict.kth.se/~cschulte/
> 
> -----Original Message-----
> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
> Of Christian Drescher
> Sent: Friday, October 30, 2009 4:18 AM
> To: users at gecode.org
> Subject: [gecode-users] Modelling Conditions on Latin Squares
> 
> Dear Subscribers,
> 
> I try to model an algebraic problem. In fact, I try to determine the
> existence of Latin Squares with certain properties. Hence, my model
> contains a Matrix of IntVar:
> 
>   Matrix<IntVarArray> mat(l, n, n);
> 
> The constraint I want to post is that for all i,j in Q:
> 
>   (i*j) * (j*i) == i
> 
> or rather
> 
>   mat(mat(i,j),mat(j,i)) == i
> 
> I tried two different approaches, but gecode's library doesn't support
> the following:
> 
>   // this doesn't work
>   post(home, mat(mat(i,j),mat(j,i)) == i);
> 
>   // this neither
>   element(home, mat, mat(i,j), mat(j,i), i);
> 
> How do I model the constraint correctly?
> 
> Best,
> Christian
> 
> 
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