title: Difference between magnitude_spectrum result available in matplotlib.mlab and numpy.abs(numpy.fft.fft(data))
body: <p>I have a simple sine wave. I am trying to find the magnitude spectrum in frequency domain.<br>
  I used the function <code>matplotlib.mlab.magnitude_spectrum(data)</code>
  I wanted to verify this result, so I tried <code>numpy.abs(numpy.fft.fft(data))</code>
  The results are different.<br>
  It should be same right? Even if I try<br>
   <code>numpy.sqrt(matplotlib.mlab.psd(data))</code>, the results are different.</p>
  
  <p>I am looking for the explanation for this.</p>