On Economic Lot Sizes with Quantity and Freight Discounts: The Mixed Discount Cases

Previous studies have incorporated both quantity and freight discounts into various inventory models and developed algorithms to determine the optimal lot sizes for all the possible discount configurations. In this study, for the cases where quantity discounts are either of the all-units or the incremental type and freight discounts are of the opposite type, we first conduct numerical experiments to show that the existing algorithm may lead to a suboptimal solution, and then modify the key steps for the existing algorithm to obtain the global optimal solution.