A comparison of solution approaches for the fixed-sequence economic lot scheduling problem

The economic lot scheduling problem (ELSP) has received much attention recently. The general version of the problem has a non-convex objective function, so it is difficult to find truly optimal solutions. We examine the three most popular heuristic approaches to the fixed-sequence ELSP. Each approach imposes one or both of these simplifying contraints: the zero-switch constraint (production of a part is started only when its inventory is depleted) and the equal-lot constraint (the lot size of a given part is constant through time). We provide a formulation that clarifies the relationships between the general problem and the three constrained versions, and compare their performances in a computational study.