Three-Phase Methodology Incorporating Scatter Search for Integrated Production, Inventory, and Distribution Routing Problem

Algorithm 1

Step  1. Generate Solutions – Generate trial solutions using Giant Tour Procedure, sweep algorithm and savings algorithm

Step  2. Improve the Solutions – Apply 2- to improve solutions generated in Step  1

Step  3. Build the reference set – put Refset = solutions in the reference set

Step  4. Initialize best solutions – make as the best solution in the current Refset,

While () do

   While (new solutions in Refset) do

   Step  5. Generate subset – generate 2 pairs of solution (2 element subset) of the Refset.

   Step  6. Combine solutions – generate new combined solutions from pairs of 2 element subsets in Step  5.

   Step  7. Improve the solutions – update inventory level, and for the affected periods (transfer from and transfer to periods)

      apply within the same period 1-0 and 1-1 exchange, and 2-.

   Step  8. Update reference set – update the reference set by maintaining the number of solutions inside the Refset

      by replacing the existing solutions with the better combined solutions.

   Step  9.    Update the best – update the in the Refset