<p>In <a href="https://github.com/mlpack/mlpack/pull/694#discussion_r70135106">src/mlpack/core/data/map_policies/missing_policy.hpp</a>:</p>
<pre style='color:#555'>> + {
> + // Nothing to initialize here.
> + }
> +
> +
> + template <typename MapType>
> + mapped_type MapString(const std::string& string,
> + const size_t dimension,
> + MapType maps,
> + std::vector<Datatype>& types)
> + {
> + // If this condition is true, either we have no mapping for the given string
> + // or we have no mappings for the given dimension at all. In either case,
> + // we create a mapping.
> + const double NaN = std::numeric_limits<double>::quiet_NaN();
> + if (missingSet.count(string) != 0 &&
</pre>
<p>I see what you mean. My thinking was, everything in <code>missingSet</code> is something we might expect to be in <code>maps</code> by the end of loading. So you can save a little bit of time by just putting everything in <code>missingSet</code> into <code>maps</code> pre-emptively. The code as it is written here only adds things into <code>maps</code> from <code>missingSet</code> when it is seen, but I am not sure it is important to have a different, standalone <code>missingSet</code>. What do you think?</p>
<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<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/694/files/a8818316a04506530e2269a2e0a32ba2f6a1c83b#r70135106">view it on GitHub</a>, or <a href="https://github.com/notifications/unsubscribe/AJ4bFEr1mCLnzc_27a07Dy3s9NXSucWjks5qTrFLgaJpZM4I07W-">mute the thread</a>.<img alt="" height="1" src="https://github.com/notifications/beacon/AJ4bFNPx5ebAbG2zs_Hz4_8XcnrDXjATks5qTrFLgaJpZM4I07W-.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/694/files/a8818316a04506530e2269a2e0a32ba2f6a1c83b#r70135106"></link>
<meta itemprop="name" content="View Pull Request"></meta>
</div>
<meta itemprop="description" content="View this Pull Request on GitHub"></meta>
</div>