title: Outer product with Numpy and Ndarray
body: <p>In one of my codes, I use numpy for matrices calculations.</p>
  
  <p>At one point, I have to do the outer product between 2 vectors to get a matrix. That's where I'm stuck. At first, I tried numpy.dot, or other matrix product, but when the arguments are both 1D, it only does the scalar product, which not what I want. Then I found that numpy.outer does exactly what I want : a column * a line.</p>
  
  <p>The thing is, my vectors are not arrays. Since they result from a numpy.dot operation, they are ndarray objects. But ndarrays do not have an outer method. I have tried everything I found on the Internet to convert my ndarrays to simple arrays. But nothing works, I still have a ndarray and the same attribute error again and again.</p>
  
  <p>Now I don't know what to try, so I wanted to check if you knew another way to do this outer product, before I do some nasty things implying cloning the values in a array.</p>
  
  <p>Thank you very much for your help.</p>