title: Elegant and/or fast equivalents of Excel SUMXMY2 (sum of square of differences of corresponding array elements) in python
body: <p>Test Sample: </p>
  
  <pre><code>a = [0.1357678   0.27303184 -0.75600229]
  b = [0.3813097  -0.72613616  0.18361217]
  </code></pre>
  
  <p>I would like to implement <code>SUMXMY2(a, b)</code> in Python without for loops</p>
  
  <p>How can I do this?</p>