title: ValueError: shape mismatch: objects cannot be broadcast to a single shape
body: <p>I am using the SciPy's <code>pearsonr(x,y)</code> method and I cannot figure out why the following error is happening:</p>
  
  <blockquote>
    <p>ValueError: shape mismatch: objects cannot be broadcast to a single shape</p>
  </blockquote>
  
  <p>It computes the first two (I am running several thousand of these tests in a loop) and then dies.  Does anyone have any ideas about what the problem might be?</p>
  
  <pre><code>r_num = n*(np.add.reduce(xm*ym))
  </code></pre>
  
  <p>this is the line in the pearsonr method that the error occurs on, any help would be much appreciated.</p>