>>> t
matrix([[1],
        [1],
        [0]])
>>> t.shape
(3, 1)
>>> w.shape
(3, 1)
>>> np.cross(t,w)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python2.7/site-packages/numpy/core/numeric.py", line 1682, in cross
    raise ValueError(msg)
ValueError: incompatible dimensions for cross product
(dimension must be 2 or 3)
>>> np.cross(t.T,w.T)
array([[-0.74535599,  0.74535599, -0.2981424 ]])
>>> t
matrix([[1],
        [1],
        [0]])
>>> w
matrix([[-0.2981424 ],
        [-0.59628479],
        [-0.74535599]])
>>> np.cross(t,w)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python2.7/site-packages/numpy/core/numeric.py", line 1682, in cross
    raise ValueError(msg)
ValueError: incompatible dimensions for cross product
(dimension must be 2 or 3)
>>> np.cross(t.T,w.T)
array([[-0.74535599,  0.74535599, -0.2981424 ]])
>>> w.shape
(3, 1)
>>> t.shape
(3, 1)
>>> A = np.matrix([[0,1],[0,0]])
>>> A
matrix([[0, 1],
        [0, 0]])
>>> x = np.matrix([1,2]).T
>>> x
matrix([[1],
        [2]])
>>> A * x
matrix([[2],
        [0]])