Originally posted by: Hosssein

Hi,

I am solving a constraint programming model by CP optimizer.  There are two sets of decision variables in the model as follows:

IloIntVarArray W(envvv, 20, 0, 10);

IloIntVarArray S(envvv, 20, 0, 10);

I want to use the following variable ordering in the CP search:

W[0], S[0] , W[1], S[1] , W[2] , S[2] , … , W[i-1],S[i-1],W[i],S[i] , ...

How can I implement this variable ordering?

IloSearchPhase accepts only one set of variables and if I use IloSearchPhaseArray cp optimizer decide about one set of variables first (for example W) and then the other set (for example S) which is not what I am looking for.

Thanks in advance for your help

Originally posted by: ChrisBr

Hello Hossein,

Why don't copy your variables in a dedicated array?

  IloIntVarArray vars(envvv);
  for(i=0; i<20; i++) {
    vars.add(W[i]);
    vars.add(S[i]);
  }

then use this new array into the search-phase.

I hope this helps,

Chris.
 

Originally posted by: Hosssein

Hi Chris.

Great ! Good Idea.

But adding a new set of variables increases the complexity of CP model. Right?

Originally posted by: ChrisBr

Hi Hossein,

Following my advice you are not creating new variables, instead you are copying existing variables in a new array. So the complexity of the model will not increase.
You might have a look to the search log and notice that you get the same number of variables in both cases.
Regards,

Chris.