ss="math display">\[
\mathrm{squared\_distance}(x,y) \ = \ \text{distance}(x,y)^2 \ = \
\textstyle \sum_{n=1}^N (x_n - y_n)^2, \]</span> where <code>N</code> is the size of x
and y. It is an error to call <code>squared_distance</code> with arguments of
unequal size.</p>
<!-- real; squared_distance; (vector x, row_vector [] y); -->
<p></p>
<p><code>real</code> <strong><code>squared_distance</code></strong><code>(vector x, row_vector [] y)</code><br>
The squared Euclidean distance between x and y</p>
<!-- rea