title: Numpy error: underflow encountered in exp
body: <p>I'm attempting to define a simple exponential and regardless of the numbers I put into the argument of the exponential I get the following:</p>
  
  <p><code>FloatingPointError: underflow encountered in exp</code></p>
  
  <p>The array I'm trying to define is as follows:</p>
  
  <pre><code>     time = np.arange(length)
       window = np.exp(-(time-512)**2/1000.0)
  </code></pre>
  
  <p>where <code>length = 4096</code>.  I'm rather inexperienced with Python and saw a similar question was answered on here somewhere but I didn't really understand it.  I should also note that this code ran before without a problem.   </p>