Freeland-Colley heuristic

Public class: FreelandColleySolver.

Reference:

J. R. Freeland and J. L. Colley Jr. (1982), A Simple Heuristic Method for Lot-Sizing in a Time-Phased Reorder System, Production and Inventory Management 23(1), 15-22.

Rule

For a replenishment beginning in period s, demand in period t>s is included while its local incremental holding cost satisfies

\[h(t-s)d_t \le A. \]

The important distinction from IPPA is that Freeland-Colley tests the next period's local marginal carrying cost; it does not sum all preceding part-period contributions in the stopping test.

Complexity

The implementation advances monotonically through the horizon:

• time O(T);
• auxiliary working memory O(T);
• result status Feasible.