The following section of code is from the createVehicles function of cost1.cpp. If the code .getPrevVar() were removed, all the other code in cost1.cpp remained the same, and the depot is located at (0,0), what would be the resulting cost coefficient?

    IloVisitToNumFunction coefFunction(_env, LastVisitCostCoef);
    vehicle.setCost(distance,
                    coefFunction,
                    vehicle.getLastVisit().getPrevVar());

Suggested Answer

Removing .getPrevVar() would mean that coefFunction uses the very last visit--the return to the depot visit--as the visit to use in calculating the cost coefficient. The coefficient is based on the x-coordinate of this visit; so if the depot were located at (0,0), then the cost would be based on a coefficient of 1. See the following code for the function LastVisitCostCoef.

IloNum LastVisitCostCoef(IloVisit visit) {
  IloNode node = visit.getNode();
  return ((IloInt)(node.getX()) % 5) + 1;
}