Talk:LU decomposition
Python example contains error
The Python example has a divide by zero error for the matrix
b = [[1, 1, 1, 1], [1, 1, -1, -1], [1, -1, 0, 0], [0, 0, 1, -1]]
although a LUP decomposition exists: [1]
The permutation matrix has to be updated at each step, but that will make the code a lot more complicated.
Example 2 pivot matrix seems to be wrong
The pivot matrix in example 2 should also swap the last two rows of the current resulting pivoted matrix: A'(3, 3) = 2 while there is a 7 right beneath it. Here is the result of the multiplication of the two matrices on wolfram alpha
The pivot matrix I propose is {{1,0,0,0},{0,0,1,0},{0,0,0,1},{0,1,0,0}}.
I did not change the article because it seemed very strange that I would be the first to see this and I therefore wonder if I'm not wrong.