Hi,

Let us use the example from https://www.linkedin.com/pulse/what-optimization-how-can-help-you-do-more-less-zoo-buses-fleischer/

OPL is a descriptive language but we can also add some javascript code before and after the solve takes place. We use the keyword execute for that and we call those preprocessing and postprocessing.

int nbKids=300;
float costBus40=500;
float costBus30=400;

// Preprocessing

execute DISPLAY_BEFORE_SOLVE
{
writeln("The challenge is to bring ",nbKids,"kids to the zoo.");
writeln("We can use 40 and 30 seats buses and the costs are ",costBus40," and ",costBus30);
writeln("So average cost per kid are ",costBus40/40, " and ",costBus30/30);
}

// Decision variables , the unknown

dvar int+ nbBus40;
dvar int+ nbBus30;

// Objective
 
minimize
 costBus40*nbBus40  +nbBus30*costBus30;
 
// Constraints
 
subject to
{
 40*nbBus40+nbBus30*30>=nbKids;
}

// Postprocessing

execute DISPLAY_After_SOLVE
{
writeln("The minimum cost is ",costBus40*nbBus40  +nbBus30*costBus30);
writeln("We will use ",nbBus40," 40 seats buses and ",nbBus30," 30 seats buses ");
}

gives

The challenge is to bring 300kids to the zoo.
We can use 40 and 30 seats buses and the costs are 500 and 400
So average cost per kid are 12.5 and 13.333333333
// solution (optimal) with objective 3800
The minimum cost is 3800
We will use 6 40 seats buses and 2 30 seats buses

regards

Many other very simple examples at https://www.linkedin.com/pulse/making-decision-optimization-simple-alex-fleischer/