Originally posted by: trxw

Hi. I have an integer array WorkingTime[1..10] with the time that every worker works. I would like to search for solutions that complain with the right order as much as possible. Meaning that the person 1 works less than 2; 2 less than 3 and so on. Something like to minimize the expression of the differente between a sorted and unsorted arrays.

But I don´t want to put it as a constrain inside the subject as sometimes is not feasible to find a solution that complies with the order of all the people. So, I don´t want this:

WorkingTimeConstraint:   
   forall (i in 1..9)
       WorkingTime[i] <= WorkingTime[i+1];

Hi,

you could try

dvar int WorkingTime[1..10] in 1..10;
 
 maximize sum(i in 1..9) (WorkingTime[i]<=WorkingTime[i+1]);

and

dvar int WorkingTime[1..10] in 1..10;
 
 minimize sum(i in 1..9) maxl(0,WorkingTime[i]-WorkingTime[i+1]);

regards

PS: Do more with less

Originally posted by: trxw

Thanks again.

Is there any way to remove one constraint from the CP model when no solution has been found?

Yes

see https://www.ibm.com/developerworks/community/forums/html/topic?id=b83f425c-8fbd-4e62-95a1-a16cbb910597&ps=25

regards 

Originally posted by: trxw

Can't figure it out... So if I have

         int CoefOrdenDeSalida=1;

then

         OrdenSalida: 
         forall (i in 1..9)
               CoefOrdenDeSalida*OrdenDeSalida[i] <= OrdenDeSalida[i+1];

I want to be able to set CoefOrdenDeSalida=0 only if no cp solution is found

main
{
thisOplModel.generate();
cp.startNewSearch();
while
(cp.next()) {  thisOplModel.postProcess(); }

thisOplModel.OrdenSalida.setCoef(thisOplModel.CoefOrdenDeSalida,0);
while
(cp.next()) {  thisOplModel.postProcess(); }
}

gives an error... Can you help me?

Hi,

you could use multiobjective and have this as a fist objective and have a second objective.

Then CPLEX will try to have the first objective as good as possible and then improve the second one. This works both for MIP and CPO:

dvar int WorkingTime[1..10] in 1..9;
 
 dexpr int obj1=(0==sum(i in 1..9) maxl(0,WorkingTime[i]-WorkingTime[i+1]));
 dexpr int obj2=WorkingTime[1];
 
 
 maximize staticLex(obj1,obj2);
 
 
 subject to
 {
 WorkingTime[2]==3;
 WorkingTime[3]==1;
 }
 
 

regards