The general problem is represented by the network in Figure 5.1. There are m
sources and n destinations, each represented by a node. The arcs represent the
routes linking the sources and the destinations. Arc (i, j) joining source i to destination
j carries two pieces of information: the transportation cost per unit, Cij, and the
amount shipped, Xij' The amount of supply at source i is ai and the amount of demand
at destinationj is bj • The objective ofthe model is to determine the unknowns
Xij that will minimize the total transportation cost while satisfying all the supply and
demand restrictions.