[gecode-users] Conditional constraints ?

[Wajid Hassan]

Hi Christian,

The problem in a nut shell is:

I have two arrays of integer variables, Array1[x] and Array2[x]. I want to
use the value assigned to the variables in Array1[] as an index of
Array2[], something like this:

rel(*this, Array2[Array1[x].val()] + (something) <= Array2[x+1]);

Is there anything wrong with the above constraint or should this work?

Best regards,
Wajid





On Mon, Feb 20, 2012 at 4:55 PM, Christian Schulte <cschulte at kth.se> wrote:

> Sorry but I have to admit that I do not understand your problem. What is
> it what you are trying to do, really?****
>
> ** **
>
> Christian****
>
> ** **
>
> --****
>
> Christian Schulte, www.ict.kth.se/~cschulte/****
>
> ** **
>
> *From:* users-bounces at gecode.org [mailto:users-bounces at gecode.org] *On
> Behalf Of *Wajid Hassan
> *Sent:* Friday, February 17, 2012 9:40 AM
> *To:* users at gecode.org
> *Subject:* [gecode-users] Conditional constraints ?****
>
> ** **
>
> Hi,****
>
> ** **
>
> I am a beginner user working on finding an optimal solution for a binding,
> scheduling and routing problem. I have done the binding and scheduling
> part, and now have some questions regarding the routing dependencies, i.e.,
> if they can be expressed in gecode or not. This might be something trivial,
> but I haven't figured it out yet.****
>
> ** **
>
> I run the Gecode model and find the appropriate binding (decision of which
> task should be assigned to which resource), this is stored in an
> IntVarArray _binding. ****
>
> ** **
>
> The routing part depends on the binding, i.e., it considers two tasks T1
> and T2, and as per the application, lets say that the output of T1 needs to
> go to the input of T2. To assign the data coming out of T1 to an
> appropriate link on the network so that it reaches T2, we need to know the
> resources to which T1 and T2 were bound. As I stated above, this
> information is itself found out by the Gecode model and stored in an
> IntVarArray _binding. ****
>
> ** **
>
> Now, I cannot figure out a way to check the value of an IntVarArray
> _binding and use it to constrain another IntVarArray. A naive approach is
> the if else, which cannot be applied on a constraint variable since it has
> not been assigned a value yet. Any suggestions would be highly appreciated.
> ****
>
> ** **
>
> BR/ Wajid****
>
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