Originally posted by: Fab10

Hi,

assume I have intvararray variables X,Y and Z for which i define an allowedAssignments constraint.

I also have an intvarMatrix variable K which should be made up with a fixed number of copies of X,Y and Z (say 3, 2 and 1).

Is there a simple way to constrain the K variable to include exactly the number of copies of X,Y and Z i would like? (somehow similar to the COUNT constraint)

Thank you.

Fabio

Originally posted by: Fab10

Hi.

To better explain my previous post, I would like to set the multiplicity of each allowed assignment of my variable X to a defined value in my variable K, much like I can do with the COUNT constraint with integer variables.

Thanks.

Fabio

Originally posted by: Philippe_Refalo

The simplest way to express your constraints is to use constraints as expressions. For the sake of simplicity, assume that K is an array, you can count and restrict the number of variables of K having the same value of X this way

(X == K[0]) + (X == K[1]) + .... + (X == K[n]) == C

I your case C is equal to 3.

Is that the constraint that you want to state ? 

It might be better for the search strategy to start to instantiate the X,Y and Z variables before the K variables to discover dead-ends earlier but it depends on other constraints of your model. 

Originally posted by: Fab10

Thank you for the suggestion.

I almost did what you proposed using "&&" instead of "+" 

(X == K[0]) && (X == K[1]) && .... && (X == K[n]) == C

where C is an IloBoolVar (I need it for other constraints)

Fabio