title: error in catkin build couldn't find package "numpy_eigen"
body: <p>The first comments led me through until I reached the error below</p>
  <p>NEW ERROR AFTER running <code>sudo apt install libeigen3-dev</code></p>
  <pre><code>    CMake Error at rpg_emvs/mapper_emvs/CMakeLists.txt:16 (find_package):
    By not providing &quot;FindEigen.cmake&quot; in CMAKE_MODULE_PATH this project has
    asked CMake to find a package configuration file provided by &quot;Eigen&quot;, but
    CMake did not find one.
  
    Could not find a package configuration file provided by &quot;Eigen&quot; with any of
    the following names:
  
  EigenConfig.cmake
  eigen-config.cmake
  
    Add the installation prefix of &quot;Eigen&quot; to CMAKE_PREFIX_PATH or set
    &quot;Eigen_DIR&quot; to a directory containing one of the above files.  If &quot;Eigen&quot;
    provides a separate development package or SDK, be sure it has been
    installed.
  </code></pre>
  <p>This is the Cmakelists.txt file</p>
  <pre><code>project(mapper_emvs)
  cmake_minimum_required(VERSION 2.8.3)
  
  find_package(catkin_simple REQUIRED)
  catkin_simple(ALL_DEPS_REQUIRED)
  
  find_package(Eigen REQUIRED)
  find_package(Boost REQUIRED system filesystem date_time thread)
  #Setting include, lib directories and definitions 
  include_directories(${${Boost_INCLUDE_DIR} ${EIGEN_INCLUDE_DIRS}})
  </code></pre>
  <p>should I try commenting the eigen add package part ?</p>
  <p>NEW ERROR After updating CMAKE file</p>
  <pre><code>/home/ubuntu/emvs_ws/src/numpy_eigen/include/numpy_eigen/boost_python_headers.hpp:23:22: fatal error: Eigen/Core: No such file or directory
  compilation terminated.
  </code></pre>
  <p>ERROR after building numpy_eigen alone</p>
  <pre><code>-- verifying file...
         file='/home/ubuntu/emvs_ws/build/eigen_catkin/eigen_src-prefix/src/3.3.4.tar.bz2'
  -- MD5 hash of
      /home/ubuntu/emvs_ws/build/eigen_catkin/eigen_src-prefix/src/3.3.4.tar.bz2
    does not match expected value
      expected: 'a7aab9f758249b86c93221ad417fbe18'
        actual: 'd41d8cd98f00b204e9800998ecf8427e'
  -- File already exists but hash mismatch. Removing...
  -- Downloading...
     dst='/home/ubuntu/emvs_ws/build/eigen_catkin/eigen_src-prefix/src/3.3.4.tar.bz2'
     timeout='none'
  -- Using src='http://bitbucket.org/eigen/eigen/get/3.3.4.tar.bz2'
  [ 13%] Building CXX object numpy_eigen/CMakeFiles/numpy_eigen_test.dir/src/autogen_test_module/test_float.cpp.o
  [ 13%] Building CXX object numpy_eigen/CMakeFiles/numpy_eigen_test.dir/src/autogen_test_module/numpy_eigen_test_module.cpp.o
  [ 18%] Building CXX object numpy_eigen/CMakeFiles/numpy_eigen_test.dir/src/autogen_test_module/test_double.cpp.o
  [ 22%] Building CXX object numpy_eigen/CMakeFiles/numpy_eigen_test.dir/src/autogen_test_module/test_uchar.cpp.o
  [ 27%] Building CXX object numpy_eigen/CMakeFiles/numpy_eigen_test.dir/src/autogen_test_module/test_int.cpp.o
  [ 31%] Building CXX object numpy_eigen/CMakeFiles/numpy_eigen_test.dir/src/autogen_test_module/test_long.cpp.o
  /home/ubuntu/emvs_ws/src/numpy_eigen/src/autogen_test_module/test_uchar.cpp:1:22: fatal error: Eigen/Core: No such file or directory
  compilation terminated.
  /home/ubuntu/emvs_ws/src/numpy_eigen/src/autogen_test_module/test_float.cpp:1:22: fatal error: Eigen/Core: No such file or directory
  compilation terminated.
  </code></pre>