How to use Eigen3 with CMake

instllation of Eigen3 library

1. Download it from Eigen;
2. Unzip it and create the build directory in the folder of the source folder;
3. Run cmake with cmake -G "MinGW Makefiles" ../ -DCMAKE_INSTALL_PREFIX=/path/to/installation/folder;
4. Run make with make install;
5. Locate the headers of Eigen and the cmake configuration files located at the installation folder.

Usage the Eigen library with cmake

1. Create a folder of cmake at the root directory of your source code;
2. Copy the configuration files of Eigen to the directory so-called cmake;

   ./
   ./main.cpp
   ./CMakeLists.txt
   ./cmake/
   ./cmake/Eigen3Config.cmake
   ./cmake/Eigen3ConfigVersion.cmake
   ./cmake/Eigen3Targets.cmake
   ./cmake/UseEigen3.cmake
   

3. Configure your CMakeLists.txt;

   cmake_minimum_required (VERSION 3.0)
   project (Name_Of_Your_Project)
   
   # important setting for accessing the eigen library
   list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake")
   find_package(Eigen3 REQUIRED)
   include_directories(${EIGEN3_INCLUDE_DIR})
   
   message("${CMAKE_MODULE_PATH}")
   message("${EIGEN3_INCLUDE_DIR}")
   
   add_executable (executable main.cpp)
   
   target_link_libraries(executable 
       PUBLIC
           Eigen
   )
   

4. Make a build directory namely build and change the working directory into that folder;
5. Run the cmake with cmake -G "MinGW Makefiles" ../ -DCMAKE_PREFIX_PATH=/path/to/installation/folder; Note It is worthy of noting that the CMAKE_PREFIX_PATH is the same as that of -DCMAKE_INSTALL_PREFIX.
6. Run make with make -j2.