From 531ecb4000c6f3f42a9641088b902503af4d9c08 Mon Sep 17 00:00:00 2001
From: Abe <abe@skyd.io>
Date: Mon, 9 Mar 2015 17:01:47 -0700
Subject: [PATCH] Get rid of hardcoded path to the internal version of eigen
 inside gtsam

---
 CMakeLists.txt                | 13 ++++++++++---
 gtsam/base/Matrix.cpp         |  4 ++--
 gtsam/base/Matrix.h           |  6 +++---
 gtsam/base/OptionalJacobian.h |  2 +-
 gtsam/base/Vector.h           |  2 +-
 5 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 38ee89760..0041c4710 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -196,8 +196,7 @@ endif()
 ### See:  http://eigen.tuxfamily.org/bz/show_bug.cgi?id=704 (Householder QR MKL selection)
 ###       http://eigen.tuxfamily.org/bz/show_bug.cgi?id=705 (Fix MKL LLT return code)
 ###       http://eigen.tuxfamily.org/bz/show_bug.cgi?id=716 (Improved comma initialization)
-# option(GTSAM_USE_SYSTEM_EIGEN "Find and use system-installed Eigen. If 'off', use the one bundled with GTSAM" OFF)
-set(GTSAM_USE_SYSTEM_EIGEN OFF)
+option(GTSAM_USE_SYSTEM_EIGEN "Find and use system-installed Eigen. If 'off', use the one bundled with GTSAM" OFF)
 
 # Switch for using system Eigen or GTSAM-bundled Eigen
 if(GTSAM_USE_SYSTEM_EIGEN)
@@ -207,13 +206,16 @@ if(GTSAM_USE_SYSTEM_EIGEN)
 	find_package(Eigen3 REQUIRED)
 	include_directories(AFTER "${EIGEN3_INCLUDE_DIR}")
 else()
-	# Use bundled Eigen include paths e.g. <gtsam/3rdparty/Eigen/Eigen/Core>
+	# Use bundled Eigen include path. 
 	set(GTSAM_EIGEN_INCLUDE_PREFIX "gtsam/3rdparty/Eigen/")
 
 	# Clear any variables set by FindEigen3
 	if(EIGEN3_INCLUDE_DIR)
 		set(EIGEN3_INCLUDE_DIR NOTFOUND CACHE STRING "" FORCE)
 	endif()
+	# Add the bundled version of eigen to the include path so that it can still be included
+	# with  #include <Eigen/Core>
+	include_directories(BEFORE ${GTSAM_EIGEN_INCLUDE_PREFIX})
 endif()
 
 # Write Eigen include file with the paths for either the system Eigen or the GTSAM-bundled Eigen
@@ -389,6 +391,11 @@ if(NOT MSVC AND NOT XCODE_VERSION)
     message(STATUS "  C compilation flags            : ${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${cmake_build_type_toupper}}")
     message(STATUS "  C++ compilation flags          : ${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_${cmake_build_type_toupper}}")
 endif()
+if(GTSAM_USE_SYSTEM_EIGEN)
+    message(STATUS "  Use System Eigen               : Yes")
+else()
+    message(STATUS "  Use System Eigen               : No")
+endif()
 if(GTSAM_USE_TBB)
 	message(STATUS "  Use Intel TBB                  : Yes")
 elseif(TBB_FOUND)
diff --git a/gtsam/base/Matrix.cpp b/gtsam/base/Matrix.cpp
index 7fa0992ca..a5836a3ac 100644
--- a/gtsam/base/Matrix.cpp
+++ b/gtsam/base/Matrix.cpp
@@ -20,8 +20,8 @@
 #include <gtsam/base/timing.h>
 #include <gtsam/base/Vector.h>
 #include <gtsam/base/FastList.h>
-#include <gtsam/3rdparty/Eigen/Eigen/SVD>  
-#include <gtsam/3rdparty/Eigen/Eigen/LU>
+#include <Eigen/SVD>
+#include <Eigen/LU>
 
 #include <boost/foreach.hpp>
 #include <boost/tuple/tuple.hpp>
diff --git a/gtsam/base/Matrix.h b/gtsam/base/Matrix.h
index 27b7ec8f7..53b040b9a 100644
--- a/gtsam/base/Matrix.h
+++ b/gtsam/base/Matrix.h
@@ -23,9 +23,9 @@
 #pragma once
 #include <gtsam/base/Vector.h>
 #include <boost/math/special_functions/fpclassify.hpp>
-#include <gtsam/3rdparty/Eigen/Eigen/Core>
-#include <gtsam/3rdparty/Eigen/Eigen/Cholesky>
-#include <gtsam/3rdparty/Eigen/Eigen/LU>
+#include <Eigen/Core>
+#include <Eigen/Cholesky>
+#include <Eigen/LU>
 #include <boost/format.hpp>
 #include <boost/tuple/tuple.hpp>
 
diff --git a/gtsam/base/OptionalJacobian.h b/gtsam/base/OptionalJacobian.h
index 2ea9d672e..81bf265a3 100644
--- a/gtsam/base/OptionalJacobian.h
+++ b/gtsam/base/OptionalJacobian.h
@@ -19,7 +19,7 @@
 
 #pragma once
 
-#include <gtsam/3rdparty/Eigen/Eigen/Dense>
+#include <Eigen/Dense>
 
 #ifndef OPTIONALJACOBIAN_NOBOOST
 #include <boost/optional.hpp>
diff --git a/gtsam/base/Vector.h b/gtsam/base/Vector.h
index fc543acc3..0869abc16 100644
--- a/gtsam/base/Vector.h
+++ b/gtsam/base/Vector.h
@@ -26,7 +26,7 @@
 #endif
 
 #include <gtsam/global_includes.h>
-#include <gtsam/3rdparty/Eigen/Eigen/Core>
+#include <Eigen/Core>
 #include <iosfwd>
 #include <list>