Fix update find eigen

Update from FindEigen to FindEigen3

cmake_modules/FindEigen3.cmake

@@ -35,14 +35,25 @@
 #
 # EIGEN_FOUND: TRUE iff Eigen is found.
 # EIGEN_INCLUDE_DIRS: Include directories for Eigen.
-#
 # EIGEN_VERSION: Extracted from Eigen/src/Core/util/Macros.h
 # EIGEN_WORLD_VERSION: Equal to 3 if EIGEN_VERSION = 3.2.0
 # EIGEN_MAJOR_VERSION: Equal to 2 if EIGEN_VERSION = 3.2.0
 # EIGEN_MINOR_VERSION: Equal to 0 if EIGEN_VERSION = 3.2.0
+# FOUND_INSTALLED_EIGEN_CMAKE_CONFIGURATION: True iff the version of Eigen
+#                                            found was built & installed /
+#                                            exported as a CMake package.
 #
 # The following variables control the behaviour of this module:
 #
+# EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION: TRUE/FALSE, iff TRUE then
+#                           then prefer using an exported CMake configuration
+#                           generated by Eigen over searching for the
+#                           Eigen components manually.  Otherwise (FALSE)
+#                           ignore any exported Eigen CMake configurations and
+#                           always perform a manual search for the components.
+#                           Default: TRUE iff user does not define this variable
+#                           before we are called, and does NOT specify
+#                           EIGEN_INCLUDE_DIR_HINTS, otherwise FALSE.
 # EIGEN_INCLUDE_DIR_HINTS: List of additional directories in which to
 #                          search for eigen includes, e.g: /timbuktu/eigen3.
 #
@@ -66,6 +77,7 @@
 macro(EIGEN_REPORT_NOT_FOUND REASON_MSG)
   unset(EIGEN_FOUND)
   unset(EIGEN_INCLUDE_DIRS)
+  unset(FOUND_INSTALLED_EIGEN_CMAKE_CONFIGURATION)
   # Make results of search visible in the CMake GUI if Eigen has not
   # been found so that user does not have to toggle to advanced view.
   mark_as_advanced(CLEAR EIGEN_INCLUDE_DIR)
@@ -83,39 +95,122 @@ macro(EIGEN_REPORT_NOT_FOUND REASON_MSG)
   return()
 endmacro(EIGEN_REPORT_NOT_FOUND)
 
-# Search user-installed locations first, so that we prefer user installs
-# to system installs where both exist.
-#
-# TODO: Add standard Windows search locations for Eigen.
-list(APPEND EIGEN_CHECK_INCLUDE_DIRS
-  /usr/local/include
-  /usr/local/homebrew/include # Mac OS X
-  /opt/local/var/macports/software # Mac OS X.
-  /opt/local/include
-  /usr/include)
-# Additional suffixes to try appending to each search path.
-list(APPEND EIGEN_CHECK_PATH_SUFFIXES
-  eigen3 # Default root directory for Eigen.
-  Eigen/include/eigen3 ) # Windows (for C:/Program Files prefix).
-
-# Search supplied hint directories first if supplied.
-find_path(EIGEN_INCLUDE_DIR
-  NAMES Eigen/Core
-  PATHS ${EIGEN_INCLUDE_DIR_HINTS}
-  ${EIGEN_CHECK_INCLUDE_DIRS}
-  PATH_SUFFIXES ${EIGEN_CHECK_PATH_SUFFIXES})
-
-if (NOT EIGEN_INCLUDE_DIR OR
+# Protect against any alternative find_package scripts for this library having
+# been called previously (in a client project) which set EIGEN_FOUND, but not
+# the other variables we require / set here which could cause the search logic
+# here to fail.
+unset(EIGEN_FOUND)
+
+# -----------------------------------------------------------------
+# By default, if the user has expressed no preference for using an exported
+# Eigen CMake configuration over performing a search for the installed
+# components, and has not specified any hints for the search locations, then
+# prefer an exported configuration if available.
+if (NOT DEFINED EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION
+    AND NOT EIGEN_INCLUDE_DIR_HINTS)
+  message(STATUS "No preference for use of exported Eigen CMake configuration "
+    "set, and no hints for include directory provided. "
+    "Defaulting to preferring an installed/exported Eigen CMake configuration "
+    "if available.")
+  set(EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION TRUE)
+endif()
+
+if (EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION)
+  # Try to find an exported CMake configuration for Eigen.
+  #
+  # We search twice, s/t we can invert the ordering of precedence used by
+  # find_package() for exported package build directories, and installed
+  # packages (found via CMAKE_SYSTEM_PREFIX_PATH), listed as items 6) and 7)
+  # respectively in [1].
+  #
+  # By default, exported build directories are (in theory) detected first, and
+  # this is usually the case on Windows.  However, on OS X & Linux, the install
+  # path (/usr/local) is typically present in the PATH environment variable
+  # which is checked in item 4) in [1] (i.e. before both of the above, unless
+  # NO_SYSTEM_ENVIRONMENT_PATH is passed).  As such on those OSs installed
+  # packages are usually detected in preference to exported package build
+  # directories.
+  #
+  # To ensure a more consistent response across all OSs, and as users usually
+  # want to prefer an installed version of a package over a locally built one
+  # where both exist (esp. as the exported build directory might be removed
+  # after installation), we first search with NO_CMAKE_PACKAGE_REGISTRY which
+  # means any build directories exported by the user are ignored, and thus
+  # installed directories are preferred.  If this fails to find the package
+  # we then research again, but without NO_CMAKE_PACKAGE_REGISTRY, so any
+  # exported build directories will now be detected.
+  #
+  # To prevent confusion on Windows, we also pass NO_CMAKE_BUILDS_PATH (which
+  # is item 5) in [1]), to not preferentially use projects that were built
+  # recently with the CMake GUI to ensure that we always prefer an installed
+  # version if available.
+  #
+  # [1] http://www.cmake.org/cmake/help/v2.8.11/cmake.html#command:find_package
+  find_package(Eigen3 QUIET
+                      NO_MODULE
+                      NO_CMAKE_PACKAGE_REGISTRY
+                      NO_CMAKE_BUILDS_PATH)
+  if (EIGEN3_FOUND)
+    message(STATUS "Found installed version of Eigen: ${Eigen3_DIR}")
+  else()
+    # Failed to find an installed version of Eigen, repeat search allowing
+    # exported build directories.
+    message(STATUS "Failed to find installed Eigen CMake configuration, "
+      "searching for Eigen build directories exported with CMake.")
+    # Again pass NO_CMAKE_BUILDS_PATH, as we know that Eigen is exported and
+    # do not want to treat projects built with the CMake GUI preferentially.
+    find_package(Eigen3 QUIET
+                        NO_MODULE
+                        NO_CMAKE_BUILDS_PATH)
+    if (EIGEN3_FOUND)
+      message(STATUS "Found exported Eigen build directory: ${Eigen3_DIR}")
+    endif()
+  endif()
+  if (EIGEN3_FOUND)
+    set(FOUND_INSTALLED_EIGEN_CMAKE_CONFIGURATION TRUE)
+    set(EIGEN_FOUND ${EIGEN3_FOUND})
+    set(EIGEN_INCLUDE_DIR "${EIGEN3_INCLUDE_DIR}" CACHE STRING
+      "Eigen include directory" FORCE)
+  else()
+    message(STATUS "Failed to find an installed/exported CMake configuration "
+      "for Eigen, will perform search for installed Eigen components.")
+  endif()
+endif()
+
+if (NOT EIGEN_FOUND)
+  # Search user-installed locations first, so that we prefer user installs
+  # to system installs where both exist.
+  list(APPEND EIGEN_CHECK_INCLUDE_DIRS
+    /usr/local/include
+    /usr/local/homebrew/include # Mac OS X
+    /opt/local/var/macports/software # Mac OS X.
+    /opt/local/include
+    /usr/include)
+  # Additional suffixes to try appending to each search path.
+  list(APPEND EIGEN_CHECK_PATH_SUFFIXES
+    eigen3 # Default root directory for Eigen.
+    Eigen/include/eigen3 # Windows (for C:/Program Files prefix) < 3.3
+    Eigen3/include/eigen3 ) # Windows (for C:/Program Files prefix) >= 3.3
+
+  # Search supplied hint directories first if supplied.
+  find_path(EIGEN_INCLUDE_DIR
+    NAMES Eigen/Core
+    HINTS ${EIGEN_INCLUDE_DIR_HINTS}
+    PATHS ${EIGEN_CHECK_INCLUDE_DIRS}
+    PATH_SUFFIXES ${EIGEN_CHECK_PATH_SUFFIXES})
+
+  if (NOT EIGEN_INCLUDE_DIR OR
+      NOT EXISTS ${EIGEN_INCLUDE_DIR})
+    eigen_report_not_found(
+      "Could not find eigen3 include directory, set EIGEN_INCLUDE_DIR to "
+      "path to eigen3 include directory, e.g. /usr/local/include/eigen3.")
+  endif (NOT EIGEN_INCLUDE_DIR OR
     NOT EXISTS ${EIGEN_INCLUDE_DIR})
-  eigen_report_not_found(
-    "Could not find eigen3 include directory, set EIGEN_INCLUDE_DIR to "
-    "path to eigen3 include directory, e.g. /usr/local/include/eigen3.")
-endif (NOT EIGEN_INCLUDE_DIR OR
-       NOT EXISTS ${EIGEN_INCLUDE_DIR})
 
-# Mark internally as found, then verify. EIGEN_REPORT_NOT_FOUND() unsets
-# if called.
-set(EIGEN_FOUND TRUE)
+  # Mark internally as found, then verify. EIGEN_REPORT_NOT_FOUND() unsets
+  # if called.
+  set(EIGEN_FOUND TRUE)
+endif()
 
 # Extract Eigen version from Eigen/src/Core/util/Macros.h
 if (EIGEN_INCLUDE_DIR)
@@ -163,5 +258,6 @@ find_package_handle_standard_args(Eigen
 # Only mark internal variables as advanced if we found Eigen, otherwise
 # leave it visible in the standard GUI for the user to set manually.
 if (EIGEN_FOUND)
-  mark_as_advanced(FORCE EIGEN_INCLUDE_DIR)
-endif (EIGEN_FOUND)
+  mark_as_advanced(FORCE EIGEN_INCLUDE_DIR
+    Eigen3_DIR) # Autogenerated by find_package(Eigen3)
+endif (EIGEN_FOUND)
\ No newline at end of file