td</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result_s</span><span class="special">));</span>
</pre>
<p>
      </p>
<p>
        Other type of query is k-nearest neighbor search. It returns some number
        of values nearest to some point in space. The default knn query may be performed
        as follows. The sequence of <code class="computeroutput"><span class="identifier">Values</span></code>
        in the re