title: sklearn agglomerative clustering linkage matrix
body: <p>I'm trying to draw a complete-link <a href="http://docs.scipy.org/doc/scipy-0.14.0/reference/generated/scipy.cluster.hierarchy.dendrogram.html"><code>scipy.cluster.hierarchy.dendrogram</code></a>, and I found that <a href="http://docs.scipy.org/doc/scipy-0.14.0/reference/generated/scipy.cluster.hierarchy.linkage.html"><code>scipy.cluster.hierarchy.linkage</code></a> is slower than <a href="http://scikit-learn.org/stable/modules/generated/sklearn.cluster.AgglomerativeClustering.html"><code>sklearn.AgglomerativeClustering</code></a>.</p>
  
  <p>However, <a href="http://scikit-learn.org/stable/modules/generated/sklearn.cluster.AgglomerativeClustering.html"><code>sklearn.AgglomerativeClustering</code></a> doesn't return the distance between clusters and the number of original observations, which <code>scipy.cluster.hierarchy.dendrogram</code> needs. Is there a way to take them?</p>