CMakeLists.txt

project(Eigen3)

cmake_minimum_required(VERSION 2.8.5)

# guard against in-source builds

if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_BINARY_DIR})
  message(FATAL_ERROR "In-source builds not allowed. Please make a new directory (called a build directory) and run CMake from there. You may need to remove CMakeCache.txt. ")
endif()

# Alias Eigen_*_DIR to Eigen3_*_DIR:

set(Eigen_SOURCE_DIR ${Eigen3_SOURCE_DIR})
set(Eigen_BINARY_DIR ${Eigen3_BINARY_DIR})

# guard against bad build-type strings

if (NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE "Release")
endif()

string(TOLOWER "${CMAKE_BUILD_TYPE}" cmake_build_type_tolower)
if(    NOT cmake_build_type_tolower STREQUAL "debug"
   AND NOT cmake_build_type_tolower STREQUAL "release"
   AND NOT cmake_build_type_tolower STREQUAL "relwithdebinfo")
  message(FATAL_ERROR "Unknown build type \"${CMAKE_BUILD_TYPE}\". Allowed values are Debug, Release, RelWithDebInfo (case-insensitive).")
endif()


#############################################################################
# retrieve version infomation                                               #
#############################################################################

# automatically parse the version number
file(READ "${PROJECT_SOURCE_DIR}/Eigen/src/Core/util/Macros.h" _eigen_version_header)
string(REGEX MATCH "define[ \t]+EIGEN_WORLD_VERSION[ \t]+([0-9]+)" _eigen_world_version_match "${_eigen_version_header}")
set(EIGEN_WORLD_VERSION "${CMAKE_MATCH_1}")
string(REGEX MATCH "define[ \t]+EIGEN_MAJOR_VERSION[ \t]+([0-9]+)" _eigen_major_version_match "${_eigen_version_header}")
set(EIGEN_MAJOR_VERSION "${CMAKE_MATCH_1}")
string(REGEX MATCH "define[ \t]+EIGEN_MINOR_VERSION[ \t]+([0-9]+)" _eigen_minor_version_match "${_eigen_version_header}")
set(EIGEN_MINOR_VERSION "${CMAKE_MATCH_1}")
set(EIGEN_VERSION_NUMBER ${EIGEN_WORLD_VERSION}.${EIGEN_MAJOR_VERSION}.${EIGEN_MINOR_VERSION})

# if the mercurial program is absent, this will leave the EIGEN_HG_CHANGESET string empty,
# but won't stop CMake.
execute_process(COMMAND hg tip -R ${CMAKE_SOURCE_DIR} OUTPUT_VARIABLE EIGEN_HGTIP_OUTPUT)
execute_process(COMMAND hg branch -R ${CMAKE_SOURCE_DIR} OUTPUT_VARIABLE EIGEN_BRANCH_OUTPUT)

# if this is the default (aka development) branch, extract the mercurial changeset number from the hg tip output...
if(EIGEN_BRANCH_OUTPUT MATCHES "default")
string(REGEX MATCH "^changeset: *[0-9]*:([0-9;a-f]+).*" EIGEN_HG_CHANGESET_MATCH "${EIGEN_HGTIP_OUTPUT}")
set(EIGEN_HG_CHANGESET "${CMAKE_MATCH_1}")
endif(EIGEN_BRANCH_OUTPUT MATCHES "default")
#...and show it next to the version number
if(EIGEN_HG_CHANGESET)
  set(EIGEN_VERSION "${EIGEN_VERSION_NUMBER} (mercurial changeset ${EIGEN_HG_CHANGESET})")
else(EIGEN_HG_CHANGESET)
  set(EIGEN_VERSION "${EIGEN_VERSION_NUMBER}")
endif(EIGEN_HG_CHANGESET)


include(CheckCXXCompilerFlag)
include(GNUInstallDirs)

set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)

#############################################################################
# find how to link to the standard libraries                                #
#############################################################################

find_package(StandardMathLibrary)


set(EIGEN_TEST_CUSTOM_LINKER_FLAGS  "" CACHE STRING "Additional linker flags when linking unit tests.")
set(EIGEN_TEST_CUSTOM_CXX_FLAGS     "" CACHE STRING "Additional compiler flags when compiling unit tests.")

set(EIGEN_STANDARD_LIBRARIES_TO_LINK_TO "")

if(NOT STANDARD_MATH_LIBRARY_FOUND)

  message(FATAL_ERROR
    "Can't link to the standard math library. Please report to the Eigen developers, telling them about your platform.")

else()

  if(EIGEN_STANDARD_LIBRARIES_TO_LINK_TO)
    set(EIGEN_STANDARD_LIBRARIES_TO_LINK_TO "${EIGEN_STANDARD_LIBRARIES_TO_LINK_TO} ${STANDARD_MATH_LIBRARY}")
  else()
    set(EIGEN_STANDARD_LIBRARIES_TO_LINK_TO "${STANDARD_MATH_LIBRARY}")
  endif()

endif()

if(EIGEN_STANDARD_LIBRARIES_TO_LINK_TO)
  message(STATUS "Standard libraries to link to explicitly: ${EIGEN_STANDARD_LIBRARIES_TO_LINK_TO}")
else()
  message(STATUS "Standard libraries to link to explicitly: none")
endif()

option(EIGEN_BUILD_BTL "Build benchmark suite" OFF)

# Disable pkgconfig only for native Windows builds
if(NOT WIN32 OR NOT CMAKE_HOST_SYSTEM_NAME MATCHES Windows)
  option(EIGEN_BUILD_PKGCONFIG "Build pkg-config .pc file for Eigen" ON)
endif()

set(CMAKE_INCLUDE_CURRENT_DIR ON)

option(EIGEN_SPLIT_LARGE_TESTS "Split large tests into smaller executables" ON)

option(EIGEN_DEFAULT_TO_ROW_MAJOR "Use row-major as default matrix storage order" OFF)
if(EIGEN_DEFAULT_TO_ROW_MAJOR)
  add_definitions("-DEIGEN_DEFAULT_TO_ROW_MAJOR")
endif()

set(EIGEN_TEST_MAX_SIZE "320" CACHE STRING "Maximal matrix/vector size, default is 320")

macro(ei_add_cxx_compiler_flag FLAG)
  string(REGEX REPLACE "-" "" SFLAG1 ${FLAG})
  string(REGEX REPLACE "\\+" "p" SFLAG ${SFLAG1})
  check_cxx_compiler_flag(${FLAG} COMPILER_SUPPORT_${SFLAG})
  if(COMPILER_SUPPORT_${SFLAG})
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${FLAG}")
  endif()
endmacro(ei_add_cxx_compiler_flag)

if(NOT MSVC)
  # We assume that other compilers are partly compatible with GNUCC

  # clang outputs some warnings for unknown flags that are not caught by check_cxx_compiler_flag
  # adding -Werror turns such warnings into errors
  check_cxx_compiler_flag("-Werror" COMPILER_SUPPORT_WERROR)
  if(COMPILER_SUPPORT_WERROR)
    set(CMAKE_REQUIRED_FLAGS "-Werror")
  endif()
  ei_add_cxx_compiler_flag("-pedantic")
  ei_add_cxx_compiler_flag("-Wall")
  ei_add_cxx_compiler_flag("-Wextra")
  #ei_add_cxx_compiler_flag("-Weverything")              # clang
  
  ei_add_cxx_compiler_flag("-Wundef")
  ei_add_cxx_compiler_flag("-Wcast-align")
  ei_add_cxx_compiler_flag("-Wchar-subscripts")
  ei_add_cxx_compiler_flag("-Wnon-virtual-dtor")
  ei_add_cxx_compiler_flag("-Wunused-local-typedefs")
  ei_add_cxx_compiler_flag("-Wpointer-arith")
  ei_add_cxx_compiler_flag("-Wwrite-strings")
  ei_add_cxx_compiler_flag("-Wformat-security")
  ei_add_cxx_compiler_flag("-Wshorten-64-to-32")
  ei_add_cxx_compiler_flag("-Wlogical-op")
  ei_add_cxx_compiler_flag("-Wenum-conversion")
  ei_add_cxx_compiler_flag("-Wc++11-extensions")
  ei_add_cxx_compiler_flag("-Wdouble-promotion")
#  ei_add_cxx_compiler_flag("-Wconversion")
  
  # -Wshadow is insanely too strict with gcc, hopefully it will become usable with gcc 6
  # if(NOT CMAKE_COMPILER_IS_GNUCXX OR (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER "5.0.0"))
  if(NOT CMAKE_COMPILER_IS_GNUCXX)
    ei_add_cxx_compiler_flag("-Wshadow")
  endif()
  
  ei_add_cxx_compiler_flag("-Wno-psabi")
  ei_add_cxx_compiler_flag("-Wno-variadic-macros")
  ei_add_cxx_compiler_flag("-Wno-long-long")
  
  ei_add_cxx_compiler_flag("-fno-check-new")
  ei_add_cxx_compiler_flag("-fno-common")
  ei_add_cxx_compiler_flag("-fstrict-aliasing")
  ei_add_cxx_compiler_flag("-wd981")                    # disable ICC's "operands are evaluated in unspecified order" remark
  ei_add_cxx_compiler_flag("-wd2304")                   # disable ICC's "warning #2304: non-explicit constructor with single argument may cause implicit type conversion" produced by -Wnon-virtual-dtor
  
  
  # The -ansi flag must be added last, otherwise it is also used as a linker flag by check_cxx_compiler_flag making it fails
  # Moreover we should not set both -strict-ansi and -ansi
  check_cxx_compiler_flag("-strict-ansi" COMPILER_SUPPORT_STRICTANSI)
  ei_add_cxx_compiler_flag("-Qunused-arguments")        # disable clang warning: argument unused during compilation: '-ansi'
  
  if(COMPILER_SUPPORT_STRICTANSI)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -strict-ansi")
  else()
    ei_add_cxx_compiler_flag("-ansi")
  endif()

  if(ANDROID_NDK)
    ei_add_cxx_compiler_flag("-pie")
    ei_add_cxx_compiler_flag("-fPIE")
  endif()
  
  set(CMAKE_REQUIRED_FLAGS "")

  option(EIGEN_TEST_SSE2 "Enable/Disable SSE2 in tests/examples" OFF)
  if(EIGEN_TEST_SSE2)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse2")
    message(STATUS "Enabling SSE2 in tests/examples")
  endif()

  option(EIGEN_TEST_SSE3 "Enable/Disable SSE3 in tests/examples" OFF)
  if(EIGEN_TEST_SSE3)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse3")
    message(STATUS "Enabling SSE3 in tests/examples")
  endif()

  option(EIGEN_TEST_SSSE3 "Enable/Disable SSSE3 in tests/examples" OFF)
  if(EIGEN_TEST_SSSE3)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mssse3")
    message(STATUS "Enabling SSSE3 in tests/examples")
  endif()

  option(EIGEN_TEST_SSE4_1 "Enable/Disable SSE4.1 in tests/examples" OFF)
  if(EIGEN_TEST_SSE4_1)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse4.1")
    message(STATUS "Enabling SSE4.1 in tests/examples")
  endif()

  option(EIGEN_TEST_SSE4_2 "Enable/Disable SSE4.2 in tests/examples" OFF)
  if(EIGEN_TEST_SSE4_2)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse4.2")
    message(STATUS "Enabling SSE4.2 in tests/examples")
  endif()

  option(EIGEN_TEST_AVX "Enable/Disable AVX in tests/examples" OFF)
  if(EIGEN_TEST_AVX)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mavx")
    message(STATUS "Enabling AVX in tests/examples")
  endif()

  option(EIGEN_TEST_FMA "Enable/Disable FMA in tests/examples" OFF)
  if(EIGEN_TEST_FMA AND NOT EIGEN_TEST_NEON)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mfma")
    message(STATUS "Enabling FMA in tests/examples")
  endif()

  option(EIGEN_TEST_AVX512 "Enable/Disable AVX512 in tests/examples" OFF)
  if(EIGEN_TEST_AVX512)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mavx512f -fabi-version=6 -DEIGEN_ENABLE_AVX512")
    message(STATUS "Enabling AVX512 in tests/examples")
  endif()

  option(EIGEN_TEST_F16C "Enable/Disable F16C in tests/examples" OFF)
  if(EIGEN_TEST_F16C)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mf16c")
    message(STATUS "Enabling F16C in tests/examples")
  endif()

  option(EIGEN_TEST_ALTIVEC "Enable/Disable AltiVec in tests/examples" OFF)
  if(EIGEN_TEST_ALTIVEC)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -maltivec -mabi=altivec")
    message(STATUS "Enabling AltiVec in tests/examples")
  endif()

  option(EIGEN_TEST_VSX "Enable/Disable VSX in tests/examples" OFF)
  if(EIGEN_TEST_VSX)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -m64 -mvsx")
    message(STATUS "Enabling VSX in tests/examples")
  endif()

  option(EIGEN_TEST_NEON "Enable/Disable Neon in tests/examples" OFF)
  if(EIGEN_TEST_NEON)
    if(EIGEN_TEST_FMA)
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mfpu=neon-vfpv4")
    else()
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mfpu=neon")
    endif()
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mfloat-abi=hard")
    message(STATUS "Enabling NEON in tests/examples")
  endif()

  option(EIGEN_TEST_NEON64 "Enable/Disable Neon in tests/examples" OFF)
  if(EIGEN_TEST_NEON64)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
    message(STATUS "Enabling NEON in tests/examples")
  endif()

  option(EIGEN_TEST_ZVECTOR "Enable/Disable S390X(zEC13) ZVECTOR in tests/examples" OFF)
  if(EIGEN_TEST_ZVECTOR)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=z13 -mzvector")
    message(STATUS "Enabling S390X(zEC13) ZVECTOR in tests/examples")
  endif()

  check_cxx_compiler_flag("-fopenmp" COMPILER_SUPPORT_OPENMP)
  if(COMPILER_SUPPORT_OPENMP)
    option(EIGEN_TEST_OPENMP "Enable/Disable OpenMP in tests/examples" OFF)
    if(EIGEN_TEST_OPENMP)
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fopenmp")
      message(STATUS "Enabling OpenMP in tests/examples")
    endif()
  endif()

else(NOT MSVC)

  # C4127 - conditional expression is constant
  # C4714 - marked as __forceinline not inlined (I failed to deactivate it selectively)
  #         We can disable this warning in the unit tests since it is clear that it occurs
  #         because we are oftentimes returning objects that have a destructor or may
  #         throw exceptions - in particular in the unit tests we are throwing extra many
  #         exceptions to cover indexing errors.
  # C4505 - unreferenced local function has been removed (impossible to deactive selectively)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHsc /wd4127 /wd4505 /wd4714")

  # replace all /Wx by /W4
  string(REGEX REPLACE "/W[0-9]" "/W4" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")

  check_cxx_compiler_flag("/openmp" COMPILER_SUPPORT_OPENMP)
  if(COMPILER_SUPPORT_OPENMP)
    option(EIGEN_TEST_OPENMP "Enable/Disable OpenMP in tests/examples" OFF)
    if(EIGEN_TEST_OPENMP)
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /openmp")
      message(STATUS "Enabling OpenMP in tests/examples")
    endif()
  endif()

  option(EIGEN_TEST_SSE2 "Enable/Disable SSE2 in tests/examples" OFF)
  if(EIGEN_TEST_SSE2)
    if(NOT CMAKE_CL_64)
      # arch is not supported on 64 bit systems, SSE is enabled automatically.
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /arch:SSE2")
    endif(NOT CMAKE_CL_64)
    message(STATUS "Enabling SSE2 in tests/examples")
  endif(EIGEN_TEST_SSE2)
endif(NOT MSVC)

option(EIGEN_TEST_NO_EXPLICIT_VECTORIZATION "Disable explicit vectorization in tests/examples" OFF)
option(EIGEN_TEST_X87 "Force using X87 instructions. Implies no vectorization." OFF)
option(EIGEN_TEST_32BIT "Force generating 32bit code." OFF)

if(EIGEN_TEST_X87)
  set(EIGEN_TEST_NO_EXPLICIT_VECTORIZATION ON)
  if(CMAKE_COMPILER_IS_GNUCXX)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mfpmath=387")
    message(STATUS "Forcing use of x87 instructions in tests/examples")
  else()
    message(STATUS "EIGEN_TEST_X87 ignored on your compiler")
  endif()
endif()

if(EIGEN_TEST_32BIT)
  if(CMAKE_COMPILER_IS_GNUCXX)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -m32")
    message(STATUS "Forcing generation of 32-bit code in tests/examples")
  else()
    message(STATUS "EIGEN_TEST_32BIT ignored on your compiler")
  endif()
endif()

if(EIGEN_TEST_NO_EXPLICIT_VECTORIZATION)
  add_definitions(-DEIGEN_DONT_VECTORIZE=1)
  message(STATUS "Disabling vectorization in tests/examples")
endif()

option(EIGEN_TEST_NO_EXPLICIT_ALIGNMENT "Disable explicit alignment (hence vectorization) in tests/examples" OFF)
if(EIGEN_TEST_NO_EXPLICIT_ALIGNMENT)
  add_definitions(-DEIGEN_DONT_ALIGN=1)
  message(STATUS "Disabling alignment in tests/examples")
endif()

option(EIGEN_TEST_NO_EXCEPTIONS "Disables C++ exceptions" OFF)
if(EIGEN_TEST_NO_EXCEPTIONS)
  ei_add_cxx_compiler_flag("-fno-exceptions")
  message(STATUS "Disabling exceptions in tests/examples")
endif()

option(EIGEN_TEST_CXX11 "Enable testing with C++11 and C++11 features (e.g. Tensor module)." OFF)

set(EIGEN_CUDA_COMPUTE_ARCH 30 CACHE STRING "The CUDA compute architecture level to target when compiling CUDA code")

include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})

# Backward compatibility support for EIGEN_INCLUDE_INSTALL_DIR
if(EIGEN_INCLUDE_INSTALL_DIR)
  message(WARNING "EIGEN_INCLUDE_INSTALL_DIR is deprecated. Use INCLUDE_INSTALL_DIR instead.")
endif()

if(EIGEN_INCLUDE_INSTALL_DIR AND NOT INCLUDE_INSTALL_DIR)
  set(INCLUDE_INSTALL_DIR ${EIGEN_INCLUDE_INSTALL_DIR}
      CACHE PATH "The directory relative to CMAKE_PREFIX_PATH where Eigen header files are installed")
else()
  set(INCLUDE_INSTALL_DIR
      "${CMAKE_INSTALL_INCLUDEDIR}/eigen3"
      CACHE PATH "The directory relative to CMAKE_PREFIX_PATH where Eigen header files are installed"
      )
endif()
set(CMAKEPACKAGE_INSTALL_DIR
    "${CMAKE_INSTALL_DATADIR}/eigen3/cmake"
    CACHE PATH "The directory relative to CMAKE_PREFIX_PATH where Eigen3Config.cmake is installed"
    )
set(PKGCONFIG_INSTALL_DIR
    "${CMAKE_INSTALL_DATADIR}/pkgconfig"
    CACHE PATH "The directory relative to CMAKE_PREFIX_PATH where eigen3.pc is installed"
    )


# similar to set_target_properties but append the property instead of overwriting it
macro(ei_add_target_property target prop value)

  get_target_property(previous ${target} ${prop})
  # if the property wasn't previously set, ${previous} is now "previous-NOTFOUND" which cmake allows catching with plain if()
  if(NOT previous)
    set(previous "")
  endif(NOT previous)
  set_target_properties(${target} PROPERTIES ${prop} "${previous} ${value}")
endmacro(ei_add_target_property)

install(FILES
  signature_of_eigen3_matrix_library
  DESTINATION ${INCLUDE_INSTALL_DIR} COMPONENT Devel
  )

if(EIGEN_BUILD_PKGCONFIG)
    configure_file(eigen3.pc.in eigen3.pc @ONLY)
    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/eigen3.pc
        DESTINATION ${PKGCONFIG_INSTALL_DIR}
        )
endif()

add_subdirectory(Eigen)

add_subdirectory(doc EXCLUDE_FROM_ALL)

include(EigenConfigureTesting)

# fixme, not sure this line is still needed:
enable_testing() # must be called from the root CMakeLists, see man page


if(EIGEN_LEAVE_TEST_IN_ALL_TARGET)
  add_subdirectory(test) # can't do EXCLUDE_FROM_ALL here, breaks CTest
else()
  add_subdirectory(test EXCLUDE_FROM_ALL)
endif()

if(EIGEN_LEAVE_TEST_IN_ALL_TARGET)
  add_subdirectory(blas)
  add_subdirectory(lapack)
else()
  add_subdirectory(blas EXCLUDE_FROM_ALL)
  add_subdirectory(lapack EXCLUDE_FROM_ALL)
endif()

# add SYCL
option(EIGEN_TEST_SYCL "Add Sycl support." OFF)
if(EIGEN_TEST_SYCL)
  set (CMAKE_MODULE_PATH "${CMAKE_ROOT}/Modules" "cmake/Modules/" "${CMAKE_MODULE_PATH}")
  include(FindComputeCpp)
endif()

add_subdirectory(unsupported)

add_subdirectory(demos EXCLUDE_FROM_ALL)

# must be after test and unsupported, for configuring buildtests.in
add_subdirectory(scripts EXCLUDE_FROM_ALL)

# TODO: consider also replacing EIGEN_BUILD_BTL by a custom target "make btl"?
if(EIGEN_BUILD_BTL)
  add_subdirectory(bench/btl EXCLUDE_FROM_ALL)
endif(EIGEN_BUILD_BTL)

if(NOT WIN32)
  add_subdirectory(bench/spbench EXCLUDE_FROM_ALL)
endif(NOT WIN32)

configure_file(scripts/cdashtesting.cmake.in cdashtesting.cmake @ONLY)

ei_testing_print_summary()

message(STATUS "")
message(STATUS "Configured Eigen ${EIGEN_VERSION_NUMBER}")
message(STATUS "")

option(EIGEN_FAILTEST "Enable failtests." OFF)
if(EIGEN_FAILTEST)
  add_subdirectory(failtest)
endif()

string(TOLOWER "${CMAKE_GENERATOR}" cmake_generator_tolower)
if(cmake_generator_tolower MATCHES "makefile")
  message(STATUS "Some things you can do now:")
  message(STATUS "--------------+--------------------------------------------------------------")
  message(STATUS "Command       |   Description")
  message(STATUS "--------------+--------------------------------------------------------------")
  message(STATUS "make install  | Install Eigen. Headers will be installed to:")
  message(STATUS "              |     <CMAKE_INSTALL_PREFIX>/<INCLUDE_INSTALL_DIR>")
  message(STATUS "              |   Using the following values:")
  message(STATUS "              |     CMAKE_INSTALL_PREFIX: ${CMAKE_INSTALL_PREFIX}")
  message(STATUS "              |     INCLUDE_INSTALL_DIR:  ${INCLUDE_INSTALL_DIR}")
  message(STATUS "              |   Change the install location of Eigen headers using:")
  message(STATUS "              |     cmake . -DCMAKE_INSTALL_PREFIX=yourprefix")
  message(STATUS "              |   Or:")
  message(STATUS "              |     cmake . -DINCLUDE_INSTALL_DIR=yourdir")
  message(STATUS "make doc      | Generate the API documentation, requires Doxygen & LaTeX")
  message(STATUS "make check    | Build and run the unit-tests. Read this page:")
  message(STATUS "              |   http://eigen.tuxfamily.org/index.php?title=Tests")
  message(STATUS "make blas     | Build BLAS library (not the same thing as Eigen)")
  message(STATUS "make uninstall| Removes files installed by make install")
  message(STATUS "--------------+--------------------------------------------------------------")
else()
  message(STATUS "To build/run the unit tests, read this page:")
  message(STATUS "  http://eigen.tuxfamily.org/index.php?title=Tests")
endif()

message(STATUS "")


set ( EIGEN_VERSION_STRING ${EIGEN_VERSION_NUMBER} )
set ( EIGEN_VERSION_MAJOR  ${EIGEN_WORLD_VERSION} )
set ( EIGEN_VERSION_MINOR  ${EIGEN_MAJOR_VERSION} )
set ( EIGEN_VERSION_PATCH  ${EIGEN_MINOR_VERSION} )
set ( EIGEN_DEFINITIONS "")
set ( EIGEN_INCLUDE_DIR "${CMAKE_INSTALL_PREFIX}/${INCLUDE_INSTALL_DIR}" )
set ( EIGEN_ROOT_DIR ${CMAKE_INSTALL_PREFIX} )

# Interface libraries require at least CMake 3.0
if (NOT CMAKE_VERSION VERSION_LESS 3.0)
  include (CMakePackageConfigHelpers)

  # Imported target support
  add_library (eigen INTERFACE)

  target_compile_definitions (eigen INTERFACE ${EIGEN_DEFINITIONS})
  target_include_directories (eigen INTERFACE
    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
    $<INSTALL_INTERFACE:${INCLUDE_INSTALL_DIR}>
  )

  # Export as title case Eigen
  set_target_properties (eigen PROPERTIES EXPORT_NAME Eigen)

  install (TARGETS eigen EXPORT Eigen3Targets)

  configure_package_config_file (
    ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Eigen3Config.cmake.in
    ${CMAKE_CURRENT_BINARY_DIR}/Eigen3Config.cmake
    PATH_VARS EIGEN_INCLUDE_DIR EIGEN_ROOT_DIR
    INSTALL_DESTINATION ${CMAKEPACKAGE_INSTALL_DIR}
    NO_CHECK_REQUIRED_COMPONENTS_MACRO # Eigen does not provide components
  )
  # Remove CMAKE_SIZEOF_VOID_P from Eigen3ConfigVersion.cmake since Eigen does
  # not depend on architecture specific settings or libraries. More
  # specifically, an Eigen3Config.cmake generated from a 64 bit target can be
  # used for 32 bit targets as well (and vice versa).
  set (_Eigen3_CMAKE_SIZEOF_VOID_P ${CMAKE_SIZEOF_VOID_P})
  unset (CMAKE_SIZEOF_VOID_P)
  write_basic_package_version_file (Eigen3ConfigVersion.cmake
                                    VERSION ${EIGEN_VERSION_NUMBER}
                                    COMPATIBILITY SameMajorVersion)
  set (CMAKE_SIZEOF_VOID_P ${_Eigen3_CMAKE_SIZEOF_VOID_P})

  # The Eigen target will be located in the Eigen3 namespace. Other CMake
  # targets can refer to it using Eigen3::Eigen.
  export (TARGETS eigen NAMESPACE Eigen3:: FILE Eigen3Targets.cmake)
  # Export Eigen3 package to CMake registry such that it can be easily found by
  # CMake even if it has not been installed to a standard directory.
  export (PACKAGE Eigen3)

  install (EXPORT Eigen3Targets NAMESPACE Eigen3:: DESTINATION ${CMAKEPACKAGE_INSTALL_DIR})

else (NOT CMAKE_VERSION VERSION_LESS 3.0)
  # Fallback to legacy Eigen3Config.cmake without the imported target
  
  # If CMakePackageConfigHelpers module is available (CMake >= 2.8.8)
  # create a relocatable Config file, otherwise leave the hardcoded paths       
  include(CMakePackageConfigHelpers OPTIONAL RESULT_VARIABLE CPCH_PATH)
  
  if(CPCH_PATH)
    configure_package_config_file (
      ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Eigen3ConfigLegacy.cmake.in
      ${CMAKE_CURRENT_BINARY_DIR}/Eigen3Config.cmake
      PATH_VARS EIGEN_INCLUDE_DIR EIGEN_ROOT_DIR
      INSTALL_DESTINATION ${CMAKEPACKAGE_INSTALL_DIR}
      NO_CHECK_REQUIRED_COMPONENTS_MACRO # Eigen does not provide components
    )
  else() 
    # The PACKAGE_* variables are defined by the configure_package_config_file
    # but without it we define them manually to the hardcoded paths
    set(PACKAGE_INIT "")
    set(PACKAGE_EIGEN_INCLUDE_DIR ${EIGEN_INCLUDE_DIR})
    set(PACKAGE_EIGEN_ROOT_DIR ${EIGEN_ROOT_DIR})
    configure_file ( ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Eigen3ConfigLegacy.cmake.in
                     ${CMAKE_CURRENT_BINARY_DIR}/Eigen3Config.cmake
                     @ONLY ESCAPE_QUOTES )
  endif()

  write_basic_package_version_file( Eigen3ConfigVersion.cmake
                                    VERSION ${EIGEN_VERSION_NUMBER}
                                    COMPATIBILITY SameMajorVersion )

endif (NOT CMAKE_VERSION VERSION_LESS 3.0)

install ( FILES ${CMAKE_CURRENT_SOURCE_DIR}/cmake/UseEigen3.cmake
                ${CMAKE_CURRENT_BINARY_DIR}/Eigen3Config.cmake
                ${CMAKE_CURRENT_BINARY_DIR}/Eigen3ConfigVersion.cmake
          DESTINATION ${CMAKEPACKAGE_INSTALL_DIR} )

# Add uninstall target
add_custom_target ( uninstall
    COMMAND ${CMAKE_COMMAND} -P ${CMAKE_CURRENT_SOURCE_DIR}/cmake/EigenUninstall.cmake)