<blockquote>
<p>After this, when I compile I am still getting errors but its different:</p>
</blockquote>

<p>This is the wrong of const correctness, it is quite easy to fix</p>

<p>change </p>

<p><code>OutputDataType&amp; OutputParameter() const { return outputParameter; }</code></p>

<p>to</p>

<p><code>OutputDataType const&amp; OutputParameter() const { return outputParameter; }</code></p>

<p>Pull request <a href="https://github.com/mlpack/mlpack/pull/536" class="issue-link js-issue-link" data-url="https://github.com/mlpack/mlpack/issues/536" data-id="137780367" data-error-text="Failed to load issue title" data-permission-text="Issue title is private">#536</a> fix this problem already</p>

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