title: Using Weka for unsupervised clustering
body: <p>I have data in the following format:</p>
  
  <pre><code>X,Y,sim(X,Y)
  </code></pre>
  
  <p>That is, a list of triples, with:</p>
  
  <ul>
  <li>X, the name of an object;</li>
  <li>Y, the name of another object;</li>
  <li>sim(X,Y), a real number expressing the distance between the two objects.</li>
  </ul>
  
  <p>Now, I want to apply some unsupervised clustering algorithm on this data.
  I had Weka in mind but I would gladly consider alternatives too.</p>