Report

Report#

Solving the problem with MILP#

  1. Evaluate the small-size model output and answer [1.5 pt]:

    • Did the solver find an optimal solution? (yes/no)

    • How many Transfer Points were opened? (number)

    • What percentage of the total objective comes from: fixed establishment cost, transport cost, and emission penalty?

  2. What is the impact of changing value of \(\lambda\) on the number of open TPs, total fixed cost, total transport cost, and total emissions? Explain why these changes occur. Your explanation should relate to trade-offs between distance, emissions, and fixed facility cost. [3 pt]

  3. Compare the small size and large size problems in terms of their computational time, number of opened TPs, and objective function value. What do these differences tell you about problem scaling? [1.5 pt]

Solving the problem with GA#

  1. What key solution property is lost when using GA instead of MILP? [0.5 pt]

  2. Is the GA a better algorithm to solve this problem compared to the MILP? Relate your answer to solve time and solution quality of the two methods. What do you think about larger size examples? [1.5 pt]

  3. Change the population size of the GA (test 10, and 50) and evaluate how this affects run time and solution quality. [1 pt]

By Nadia Pourmohammadzia, Delft University of Technology. CC BY 4.0, more info on the Credits page of Workbook

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