Motivated by the recent success of integer programming based procedures for computing
discrete forecast horizons, we consider two-product variants of the classical dynamic lotsize
model. In the first variant, we impose a warehouse capacity constraint on the total
ending inventory of the two products in any period. In the second variant, the two
products have both individual and joint setup costs for production. To our knowledge,
there are no known procedures for computing forecast horizons for these variants.
Under the assumption that future demands are discrete, we characterize forecast
horizons for these two variants as feasibility/optimality questions in 0–1 mixed integer
programs. A detailed computational study establishes the effectiveness of our approach
and enables us to gain valuable insights into the behavior of minimal forecast horizons.