title: Are Entropy results order-dependent when using SameTest
body: <p>Mathematica's <code>Entropy</code> function is order-dependent when using the <code>SameTest</code> option.</p>
  
  <p>That is:</p>
  
  <pre><code>Entropy[RandomSample[Range[11]], SameTest-&gt;(Abs[#1-#2]&gt;1&amp;) ]
  </code></pre>
  
  <p>will give different results many times.</p>
  
  <p>I assume that this is because <code>Entropy[]</code> is in fact <code>Union</code>-izing the list, but, unlike <code>Union</code>, it is actually replacing one of the <code>SameTest</code> values with the other, and this replacement is order sensitive.</p>
  
  <p>Is this a bug or is it the expected behaviour?</p>