Originally posted by: SystemAdmin

[agus said:]

Hi,

Is it possible to display the binding constraints and shadow prices of the solution? and if it is how?

thanks

Agus
#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: SystemAdmin

[Selvaprabu said:]

Hi Agus,

I'm not sure of how to do this in the OPL IDE but here is how I do it in OPL script.

Name the constraint you want to check, say you name it C1. You can use "C1.slack" to check if a constraint is binding. Similarly, you can use "C1.dual" to extract the shadow price.

I'm not sure if this is the best way, but it works.

- Selva
#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: SystemAdmin

[agus said:]

Hi Selva,

Thanks for the response, but I still have problem with it.

here is my constraint:

A:
forall (i, j in Flights: i.flightID!=j.flightID, u in (i.realNodes inter j.realNodes): u!= last(i.realNodes))
        (t[j][u] - t[i][u] >= (t[i][next(i.realNodes,u)]-t[i][u])/luv[u][next(i.realNodes,u)]*200 - (1-y[i][j][u])*1000000);


I tried to put

execute
{
  writeln( A.name," ",A.UB," ",A.LB," ",A.dual," ",A.slack);
}


at the end of the model, but it gave me this result:

// solution (optimal) with objective 4426.46699999603
A undefined undefined undefined undefined

I saw the example where it works:

dvar float x in 5..20;
dvar float y in 0..20;

maximize x+y;

subject to
{
  ct1:2*x+y<=10;<br />  ct2:x<=7;<br /> }

execute
{
  writeln( ct1.name," ",ct1.UB," ",ct1.LB," ",ct1.dual," ",ct1.slack);
  writeln( ct2.name," ",ct2.UB," ",ct2.LB," ",ct2.dual," ",ct2.slack);
}


I just don't understand why it doesn't work with my model.

Can someone help me with this?

Thanks a lot

agus

#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: SystemAdmin

[alain.chabrier said:]

Hi,

in  your first example, A is an array of constraints.

You should use A[i][j].LB, etc

See another topic in this forum form today with an exmaple.
#DecisionOptimization
#OPLusingCPLEXOptimizer