This lesson's interactive features are locked, please to keep using them

Tableau Solution

Let's add a method to our class to get the current solution from the state of the tableau. Remember, this isn't the final solution; it's just the solution of the current tableau, which we'll update in the next assignments.

Assignment

Complete the get_solution_from_tableau method. It should return a tuple containing 1) a list of numbers that represent the coefficients of each variable in the equation, and 2) the current value of the profit variable.

For example, this tableau:

[1.0, 0.0, 1.0, 0.0, 0.0, 250.0]
[0.0, 1.0, 0.0, 1.0, 0.0, 200.0]
[1.0, 1.0, 0.0, 0.0, 1.0, 300.0]
[-5.0, -1.0, 0.0, 0.0, 0.0, 0.0]

Would return the following tuple:

([0, 0, 250.0, 200.0, 300.0], 0.0)

Create an empty list called columns. We're going to transpose the matrix to be columns x rows instead of rows x columns to make the columns easier to work with. This won't change the underlying values.
For the index of each column in the constraint rows (self.rows):
1. Create a new list called column filled with zeros, with a length equal to the number of constraint rows.
2. For the index of each constraint row:
  1. Set the column's value at the row index equal to the old tableau's value, e.g. self.rows[row_index][column_index].
3. Append the new column to columns.
columns is our new tableau with the column index first, and the row index second.
Create a new list called results.
For each column index in the columns matrix except for the last one:
1. If the column contains all 0s and a single 1:
  1. Find the value in the last column of the tableau that shares an index with the 1.
  2. Append that value to the results list.
2. Otherwise, append a 0 to the results list.
Return the results list and the last value of self.objective as a tuple.