Instances for the two-stage fixed-charge transportation problem

This repository contains a collection of instance files used in the computational experiments reported in: Calvete, H. I., Galé, C., Iranzo, J. A., & Toth, P. (2018). A matheuristic for the two-stage fixed-charge transportation problem. Computers & Operations Research, 95, 113–122. The instances correspond to large-scale test cases for the two-stage fixed-charge transportation problem and are provided as plain text files. File name convention Each .txt file name follows the format pN_I_J_K.txt, where N is the instance number, I is the number of plants, J is the number of depots, and K is the number of customers. For example, the file p1_2_4_6.txt corresponds to instance 1 with I = 2 plants, J = 4 depots and K = 6 customers. File structure Each .txt file contains all the data required to define one instance of the problem, organized as follows: I, J, K: integer values indicating the number of plants, depots and customers, respectively. demand: a vector of length K specifying the demand of each customer. supply: a vector of length I specifying the production capacity of each plant. variableCost1: an I × J matrix where element (i, j) represents the unit variable transportation cost from plant i to depot j. variableCost2: a J × K matrix where element (j, k) represents the unit variable transportation cost from depot j to customer k. fixedCost1: an I × J matrix where element (i, j) represents the fixed cost incurred if the link from plant i to depot j is used. fixedCost2: a J × K matrix where element (j, k) represents the fixed cost incurred if the link from depot j to customer k is used. Contact For any questions or further information regarding these instances, please contact José A. Iranzo at [e-mail]