title: Undefined Reference to LAPACK wrapper of Armadillo
body: <p>I have a question regarding the use of Armadillo.</p>
  
  <p>I'm using Ubuntu 12.10, and the gcc compiler in Code::Blocks.
  I installed LAPACK and BLAS using the synaptic package manager. I also installed Armadillo once using the synaptic package manager, once by hand with CMake. CMake found the LAPACK and BLAS libraries while making the configurations for the armadillo compilation. Furthermore, I linked the libraries of BLAS and LAPACK in Code::Blocks in 'Build Options"->"Linker'`.</p>
  
  <p>However, whenever I want to build my project, I get the error message:</p>
  
  <pre><code> In function `void arma::lapack::getrf&lt;double&gt;(int*, int*, double*, int*, int*, int*)':|
  /usr/include/armadillo_bits/lapack_wrapper.hpp|41|undefined reference to `wrapper_dgetrf_'|
  </code></pre>
  
  <p>It obviously means that armadillo cannot find LAPACK, but what did I do wrong?</p>
  
  <p>I also discommented the respective lines in the armadillo_bits/config.hpp file, so that it looks like this:  </p>
  
  <pre><code>    #if !defined(ARMA_USE_LAPACK)
      //#define ARMA_USE_LAPACK
      //// Uncomment the above line if you have LAPACK or a high-speed replacement for LAPACK,
      //// such as Intel MKL, AMD ACML, or the Accelerate framework.
      //// LAPACK is required for matrix decompositions (eg. SVD) and matrix inverse.
      #endif
  
      #if !defined(ARMA_USE_BLAS)
      //#define ARMA_USE_BLAS
      //// Uncomment the above line if you have BLAS or a high-speed replacement for BLAS,
      //// such as OpenBLAS, GotoBLAS, Intel MKL, AMD ACML, or the Accelerate framework.
      //// BLAS is used for matrix multiplication.
      //// Without BLAS, matrix multiplication will still work, but might be slower.
      #endif
  
      /* #undef ARMA_USE_WRAPPER */
      //// Comment out the above line if you're getting linking errors when compiling your programs,
      //// or if you prefer to directly link with LAPACK and/or BLAS.
      //// You will then need to link your programs directly with -llapack -lblas instead of -larmadillo
  </code></pre>
  
  <p>The error appears first when I try to set up a matrix with integers, so </p>
  
  <pre><code>  Mat&lt;int&gt; element_nodes;
  </code></pre>
  
  <p>I would appreciate helpful answers. I did search the internet for a couple of hours. Also, if you need more source code, let me know.</p>