<p>In <a href="https://github.com/mlpack/mlpack/pull/762#discussion_r75535801">src/mlpack/core/tree/binary_space_tree/binary_space_tree.hpp</a>:</p>
<pre style='color:#555'>&gt; +  template&lt;typename VecType&gt;
&gt; +  BinarySpaceTree&amp; GetFurthestChild(
&gt; +      const VecType&amp; point,
&gt; +      typename boost::enable_if&lt;IsVector&lt;VecType&gt; &gt;::type* = 0);
&gt; +
&gt; +  /**
&gt; +   * Return the nearest child node to the given query node.  If it can&#39;t decide
&gt; +   * it will return a null pointer.
&gt; +   */
&gt; +  BinarySpaceTree* GetNearestChild(const BinarySpaceTree&amp; queryNode);
&gt; +
&gt; +  /**
&gt; +   * Return the furthest child node to the given query node.  If it can&#39;t decide
&gt; +   * it will return a null pointer.
&gt; +   */
&gt; +  BinarySpaceTree* GetFurthestChild(const BinarySpaceTree&amp; queryNode);
</pre>
<p>I don't think you're using these overloads anywhere. Can I suggest returning a <code>size_t</code> instead of a reference or pointer? You can return <code>NumChildren()</code> to indicate an invalid child. This avoids the issues with returning <code>*this</code> and there's never a need to return <code>NULL</code>. The user can check on their own whether or not the results are valid and we also manage to keep our TreeType API simpler. What do you think?</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">&mdash;<br />You are receiving this because you are subscribed to this thread.<br />Reply to this email directly, <a href="https://github.com/mlpack/mlpack/pull/762/files/f8ddd58ece06362024944a6533f68074a6b27ef7#r75535801">view it on GitHub</a>, or <a href="https://github.com/notifications/unsubscribe-auth/AJ4bFL9nUtpHRRUdGy-iVrK-MZyKoLoKks5qhf44gaJpZM4JlKcS">mute the thread</a>.<img alt="" height="1" src="https://github.com/notifications/beacon/AJ4bFEllG4Z-G1soKiLHhE71kKJLydnmks5qhf44gaJpZM4JlKcS.gif" width="1" /></p>
<div itemscope itemtype="http://schema.org/EmailMessage">
<div itemprop="action" itemscope itemtype="http://schema.org/ViewAction">
  <link itemprop="url" href="https://github.com/mlpack/mlpack/pull/762/files/f8ddd58ece06362024944a6533f68074a6b27ef7#r75535801"></link>
  <meta itemprop="name" content="View Pull Request"></meta>
</div>
<meta itemprop="description" content="View this Pull Request on GitHub"></meta>
</div>

<script type="application/json" data-scope="inboxmarkup">{"api_version":"1.0","publisher":{"api_key":"05dde50f1d1a384dd78767c55493e4bb","name":"GitHub"},"entity":{"external_key":"github/mlpack/mlpack","title":"mlpack/mlpack","subtitle":"GitHub repository","main_image_url":"https://cloud.githubusercontent.com/assets/143418/17495839/a5054eac-5d88-11e6-95fc-7290892c7bb5.png","avatar_image_url":"https://cloud.githubusercontent.com/assets/143418/15842166/7c72db34-2c0b-11e6-9aed-b52498112777.png","action":{"name":"Open in GitHub","url":"https://github.com/mlpack/mlpack"}},"updates":{"snippets":[{"icon":"PERSON","message":"@rcurtin in #762: I don't think you're using these overloads anywhere. Can I suggest returning a `size_t` instead of a reference or pointer? You can return `NumChildren()` to indicate an invalid child. This avoids the issues with returning `*this` and there's never a need to return `NULL`. The user can check on their own whether or not the results are valid and we also manage to keep our TreeType API simpler. What do you think?"}],"action":{"name":"View Pull Request","url":"https://github.com/mlpack/mlpack/pull/762/files/f8ddd58ece06362024944a6533f68074a6b27ef7#r75535801"}}}</script>