On 27 Jun 2011, at 15:41, Dongrui She wrote:
> Hi All,
>
> I am new to gecode and I have a question about how to model a constraint:
> sum{a_i*b_i}
>
> where a is an integer variable array and b is a bool variable array.
> Basically I want to constrain the sum of some elements in a.
>
> It seems that I cannot directly specify such constraint. Right now what I can
> think of is to use channel constraint to create an integer array with the same
> value as b and use it to specify the constraint I want.
>
> Is this the right way to go?
You could do that, but I suspect it would be more efficient to introduce
temporary integer variables c_i such that
b -> c_i = a_i
and
!b -> c_i = 0
and then use the sum of the c_i.
Cheers,
Guido
--
Guido Tack, http://people.cs.kuleuven.be/~guido.tack/
_______________________________________________
Gecode users mailing list
[email protected]
https://www.gecode.org/mailman/listinfo/gecode-users
