Inverse of Diagonal Matrix

Problem

Return the inverse of a square diagonal matrix: reciprocals on the diagonal and zeros elsewhere.

If any diagonal entry is 0, the matrix is singular; return None.

Hint

Invert each nonzero diagonal entry; off-diagonal entries stay 0.

case 1

in: [[[2,0],[0,4]]]

expected: [[0.5,0],[0,0.25]]

case 2

in: [[[1,0,0],[0,2,0],[0,0,5]]]

expected: [[1,0,0],[0,0.5,0],[0,0,0.2]]

case 3

in: [[[1,0],[0,1]]]

expected: [[1,0],[0,1]]

case 4

in: [[[0,0],[0,2]]]

expected: null

Starter codePython

def inverse_diagonal(A):
    # Your code here
    pass

4 test cases · run your code against them in the editor