title: Numpy: add a vector to matrix column wise
body: <pre><code>a
  Out[57]: 
  array([[1, 2],
         [3, 4]])
  
  b
  Out[58]: 
   array([[5, 6],
         [7, 8]])
  
  In[63]: a[:,-1] + b
  Out[63]: 
  array([[ 7, 10],
         [ 9, 12]])
  </code></pre>
  
  <p>This is row wise addition. How do I add them column wise to get </p>
  
  <pre><code>In [65]: result
  Out[65]: 
  array([[ 7,  8],
         [11, 12]])
  </code></pre>
  
  <p>I don't want to transpose the whole array, add and then transpose back. Is there any other way?</p>