import eigen to cmake

CMakeLists.txt

@@ -23,6 +23,7 @@ include(external/zlib)      # download, build, install zlib
 include(external/gflags)    # download, build, install gflags
 include(external/glog)      # download, build, install glog
 include(external/gtest)     # download, build, install gtest
+include(external/eigen)     # download eigen
 include(external/pybind11)  # download pybind11
 include(external/protobuf)  # download, build, install protobuf
 include(external/python)    # find python and set path

cmake/external/eigen.cmake

+INCLUDE(ExternalProject)
+
+SET(EIGEN_SOURCE_DIR ${THIRD_PARTY_PATH}/eigen3)
+
+INCLUDE_DIRECTORIES(${EIGEN_SOURCE_DIR}/src/extern_eigen3)
+
+ExternalProject_Add(
+    extern_eigen3
+    ${EXTERNAL_PROJECT_LOG_ARGS}
+    GIT_REPOSITORY  "https://github.com/RLovelett/eigen.git"
+    GIT_TAG         "master"
+    PREFIX          ${EIGEN_SOURCE_DIR}
+    UPDATE_COMMAND  ""
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND     ""
+    INSTALL_COMMAND   ""
+    TEST_COMMAND      ""
+)
+
+if (${CMAKE_VERSION} VERSION_LESS "3.3.0")
+    set(dummyfile ${CMAKE_CURRENT_BINARY_DIR}/eigen3_dummy.c)
+    file(WRITE ${dummyfile} "const char * dummy_eigen3 = \"${dummyfile}\";")
+    add_library(eigen3 STATIC ${dummyfile})
+else()
+    add_library(eigen3 INTERFACE)
+endif()
+
+add_dependencies(eigen3 extern_eigen3)
+
+LIST(APPEND external_project_dependencies eigen3)