title: Building opencv 3.1 on windows - where do I specify the LAPACK library location?
body: <p>For building opencv 3.1 I'm using cmake with Visual Studio 2013. I downloaded the dependencies as shown here: <a href="http://docs.opencv.org/3.1.0/d3/d52/tutorial_windows_install.html" rel="nofollow">http://docs.opencv.org/3.1.0/d3/d52/tutorial_windows_install.html</a><br>
  While configuring cmake, the first thing it shows is:  </p>
  
  <pre><code>FP16: Compiler support is available
  A library with BLAS API not found. Please specify library location.
  LAPACK requires BLAS
  A library with LAPACK API not found. Please specify library location.
  </code></pre>
  
  <p>The problem is, that I don't know how to specify the location. For the "Eigen" library I set the library path myself (EIGEN_INCLUDE_PATH, which is pre defined) and cmake says:  </p>
  
  <pre><code>Other third-party libraries:
      Use IPP:                     NO
      Use IPP Async:               NO
      Use Lapack:                  NO
      Use Eigen:                   YES (ver 3.2.10)
      Use Cuda:                    NO
      Use OpenCL:                  YES
      Use OpenVX:                  NO
      Use custom HAL:              NO
  </code></pre>
  
  <p>but there is no pre defined variable for LAPACK. I also tried to put the *.lib and header files in a subdirectory, which I downloaded from <a href="http://icl.cs.utk.edu/lapack-for-windows/" rel="nofollow">http://icl.cs.utk.edu/lapack-for-windows/</a>, in the hope if cmake somehow finding the library.</p>
  
  <p>I have to build opencv 3.1 myself, because in the distributed version, the extra modules are disabled. It builds without LAPACK, but my guess is, that I will loose a lot of performance.</p>
  
  <p>Thank you very much for your help!</p>