title: MLPACK | Compile Time Issue | Linux
body: <p>I have followed <a href="https://www.mlpack.org/doc/stable/doxygen/build.html" rel="nofollow noreferrer">this</a> documentation to set up mlpack on my pc.
  I have compiled the <a href="https://www.mlpack.org/doc/stable/doxygen/sample.html" rel="nofollow noreferrer">Covariance Computation</a> code.</p>
  <pre><code>g++ covariance.cc -o a -fopenmp -std=c++11
  </code></pre>
  <p>After compiling I got the following errors.</p>
  <p><a href="https://i.stack.imgur.com/32kQ3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/32kQ3.png" alt="enter image description here" /></a>
  <a href="https://i.stack.imgur.com/ovUvi.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ovUvi.png" alt="enter image description here" /></a></p>
  <p>What should I do?</p>