numpy.matrix.getI

method

matrix.getI(self) [source]

Returns the (multiplicative) inverse of invertible self.

Parameters

None

Returns

retmatrix object

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

Raises

numpy.linalg.LinAlgError: Singular matrix

If self is singular.

See also

linalg.inv

Examples

>>> m = np.matrix('[1, 2; 3, 4]'); m
matrix([[1, 2],
        [3, 4]])
>>> m.getI()
matrix([[-2. ,  1. ],
        [ 1.5, -0.5]])
>>> m.getI() * m
matrix([[ 1.,  0.], # may vary
        [ 0.,  1.]])