title: How to broadcast an array by columns?
body: <p>I want to add every columns of a matrix to a numpy array, but <code>numpy.broadcast</code> only allows to add every rows of a matrix to an array. How can I do this?</p>
  
  <p>My idea is to first transpose the matrix then add it to the array then transpose back, but this uses two transposes. Is there a function to do it directly?</p>