`numpy.matrixlib.defmatrix:matrix.I`

Signature

def I(self)

Returns the (multiplicative) inverse of invertible self.

ret : matrix object: If self is non-singular, ret is such that ret * self == self * ret == np.matrix(np.eye(self[0,:].size)) all return True.

m = np.matrix('[1, 2; 3, 4]'); m
m.getI()

✓

matrix([[-2. ,  1. ],
        [ 1.5, -0.5]])

m.getI() * m

✗

matrix([[1.0000e+00, 4.4409e-16],
        [0.0000e+00, 1.0000e+00]])