The objective in this model is to minimize total costs, which is the sum of the shipping costs and fixed plant costs. This is computed using the following expression:

! The objective;

   [TTL_COST] MIN = @SUM( ARCS: COST * VOL) +

    @SUM( PLANTS: FCOST * OPEN);

The shipping cost component of the objective is computed with:

@SUM( ARCS: COST * VOL)

while the fixed plant costs component is given by:

@SUM( PLANTS: FCOST * OPEN)