title: Scipy whitening in advance of kmeans clustering
body: <p>I'm trying to cluster some data using <code>kmeans</code> from <code>sklearn.cluster</code>. But I want to whiten my data first. I have a Pandas df with the following three columns (there are a couple hundred rows):</p>
  
  <pre><code>1) zipcode
  2) highclust
  3) callclust
  </code></pre>
  
  <p>I want to whiten (using <code>scipy.cluster.vq.whiten</code>). From what I've researched so far, the df columns have to converted to a matrix before whitening. So I did:</p>
  
  <p><code>features = df.as_matrix(columns = ['highclust', 'callclust'])</code></p>
  
  <p>Then I used <code>whiten(features)</code>.</p>
  
  <p>That worked fine, but now I want to get those values back onto the original df. </p>
  
  <p>The problem is that I've got no values to merge it back with. If I bring <code>zipcode</code> into <code>features</code> when I create it, the zipcode gets whitened along with <code>highclust</code> and <code>callclust</code>, rendering it useless. </p>