title: Including Eigen
body: <p>I've included the <a href="http://eigen.tuxfamily.org/index.php?title=Main_Page" rel="nofollow">Eigen</a> headers in a C++ project in Eclipse. When I try to build I get this error:</p>
  
  <pre><code>Symbol 'Eigen' could not be resolved    Semantic Error
  </code></pre>
  
  <p>From what I understand, this is a linker error, but Eigen is a header-only project and thus has no library to link against. The code that throws the error follows the basic tutorial they  provide, and the offending snippet looks like this:</p>
  
  <pre><code>#include &lt;Eigen/Dense&gt;
  
  using namespace Eigen;
  </code></pre>
  
  <p>What am I doing wrong? If it helps, I'm running this on Linux. Thanks.</p>