title: Python NLTK: What's the difference between total entropy and per-word entropy?
body: <p>I'm required to find both the total cross entropy and per-word cross entropy of a given text using NLTK.</p>
  
  <p>Specifically I'm using the entropy function here...
  <a href="http://www.nltk.org/_modules/nltk/model/ngram.html" rel="nofollow">http://www.nltk.org/_modules/nltk/model/ngram.html</a></p>
  
  <p>...but I'm unsure whether this calculates the total or per-word cross entropy and how to calculate the other one.</p>
  
  <p>Can anyone offer me some insight?</p>