Estou meio que desesperada: para meus estudos, preciso trabalhar com Eigen e CMake. Sou capaz de usar o Eigen se copiar toda a biblioteca nos diretórios em que meu compilador parece por padrão, mas assim que tentar encontrá-lo via
find_package(Eigen3 REQUIRED)
Estou tendo o erro a seguir:

CMake Error at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
  Could NOT find Eigen3 (missing: EIGEN3_INCLUDE_DIR EIGEN3_VERSION_OK)
  (Required is at least version "2.91.0")
Call Stack (most recent call first):
  /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
  FindEigen3.cmake:76 (find_package_handle_standard_args)
  CMakeLists.txt:8 (find_package)<p></p>

-- Configuring incomplete, errors occurred!



Now I searched for solutions but all I those I tried (also those available on stackoverflow: 

Find package Eigen3 for CMake 
or 
CMake Can't find Eigen3 )
did not work.
My Eigen Version (according to the Macros in Core/util/Macros.h) is 3.2.5.
I keep the Eigen directory in /usr/local/include, I use the FindEigen3.cmake which comes with the Eigen library and my CMakeLists.txt looks as follows: 



cmake_minimum_required(VERSION 2.8)
project(Test)

set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR})
find_package(Eigen3 REQUIRED)
include_directories(${EIGEN3_INCLUDE_DIR})
message("Found Eigen3 in: ${EIGEN3_INCLUDE_DIR}")

add_executable(main test.cpp)


Has anyone an idea what's going wrong?

Kind regards,
Julien