In [6]:

    

from pylab import *


    

In [7]:

    

A=matrix([ [9,8,6],[1,2,7],[4,9,2],[6,0,5] ])


    

In [8]:

    

A


    

    
Out[8]:





matrix([[9, 8, 6],
        [1, 2, 7],
        [4, 9, 2],
        [6, 0, 5]])

In [9]:

    

A.T


    

    
Out[9]:





matrix([[9, 1, 4, 6],
        [8, 2, 9, 0],
        [6, 7, 2, 5]])

In [10]:

    

A*A


    

    




---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-10-efb08c3213b7> in <module>()
----> 1 A*A

/Users/bblais/anaconda/lib/python2.7/site-packages/numpy/matrixlib/defmatrix.pyc in __mul__(self, other)
    339         if isinstance(other, (N.ndarray, list, tuple)) :
    340             # This promotes 1-D vectors to row vectors
--> 341             return N.dot(self, asmatrix(other))
    342         if isscalar(other) or not hasattr(other, '__rmul__') :
    343             return N.dot(self, other)

ValueError: shapes (4,3) and (4,3) not aligned: 3 (dim 1) != 4 (dim 0)

In [11]:

    

A*A.T


    

    
Out[11]:





matrix([[181,  67, 120,  84],
        [ 67,  54,  36,  41],
        [120,  36, 101,  34],
        [ 84,  41,  34,  61]])

In [12]:

    

A=matrix([ 1,3,1,0,1,2 ])
print(A)


    

    




[[1 3 1 0 1 2]]

In [13]:

    

A.shape=(3,2)


    

In [14]:

    

A


    

    
Out[14]:





matrix([[1, 3],
        [1, 0],
        [1, 2]])

In [15]:

    

B=matrix([0,0,7,5,2,1])
B.shape=(3,2)


    

In [16]:

    

B


    

    
Out[16]:





matrix([[0, 0],
        [7, 5],
        [2, 1]])

In [17]:

    

A+B


    

    
Out[17]:





matrix([[1, 3],
        [8, 5],
        [3, 3]])

In [18]:

    

A-B


    

    
Out[18]:





matrix([[ 1,  3],
        [-6, -5],
        [-1,  1]])

In [19]:

    

A*B.T


    

    
Out[19]:





matrix([[ 0, 22,  5],
        [ 0,  7,  2],
        [ 0, 17,  4]])

In [20]:

    

A.T*B


    

    
Out[20]:





matrix([[9, 6],
        [4, 2]])

In [21]:

    

x=matrix([20,50])
wA=matrix([.3,.2])
wB=matrix([-.75,.3])


    

In [22]:

    

x*wA.T


    

    
Out[22]:





matrix([[ 16.]])

In [ ]: