title: fatal error: Eigen/Core: No such file or directory compilation terminated
body: <p>I recently change my OS to the last mint cinamon. Compiling one of the library I need (and that I used to used without problem), I get this message: </p>
  
  <pre><code>fatal error: Eigen/Core: No such file or directory compilation terminated.
  </code></pre>
  
  <p>I don't know what to do.
  Thanks for the help.</p>