Transportation Flashcards
Describe the transportation problem
It’s concerned with moving some commodity from a source to some destination.
We can model the problem as a list of factories (sources) with production rates, warehouses (destinations) with capacities and a weighted adjacency matrix between the two (transition costs).
Describe the northwest corner method.
With the northwest corner method, we start in the northwest corner.
We try to maximize how much is transported from the current factory to the current warehouse.
Afterwards, we continue to do this for each square on a zig-zag pattern towards the southeast corner.
Describe the least cost method.
In the least cost method, we look through the adjacency matrix to find the cheapest transition cost. We then want to transport as much as the factory/warehouse combination allows us.
Then we look through the adjacency matrix for the next cheapest factory/warehouse combination, and move as much as that allows.
We continue to do this while the factories and warehouses can deliver more.
Describe the stepping stone algorithm.
We ask ourselves: if we assign one more unit to some empty factory/warehouse combination, will this decrease the total cost?
We try doing this by adding 1 unit to some f/w combination. This will unbalance the adjacent row and column. To balance these, we remove one unit from the row/column (Typically from the most expensive f/w combination). This will make both of those unbalanced, so we need to balance both of those until an equilibrium has been reached.
