Option to build with VTK 7, now that Arch (and others) are shipping with that.

CMakeLists.txt

   message(FATAL_ERROR "Lemma requires that git is installed and in the path of your machine")
 endif(NOT HAVEGIT)
 
-# FIND_PROGRAM(HAVEHG hg
-#   PATHS /usr/bin/ /bin ENV PATH NO_DEFAULT_PATH
-# )
-# if(NOT HAVEHG)
-#   message(STATUS "Mercurial (hg) was not found.")
-# endif(NOT HAVEHG)
+FIND_PROGRAM(HAVEHG hg
+  PATHS /usr/bin/ /bin ENV PATH NO_DEFAULT_PATH
+)
+if(NOT HAVEHG)
+   message(STATUS "Mercurial (hg) was not found.")
+endif(NOT HAVEHG)
 
 option(BUILD_SHARED_LIBS OFF)
 if(BUILD_SHARED_LIBS)
 include(ExternalProject)
 # Eigen, this header-library is used extensively for linear algebra, matrices, and arrays
 # Mercurial (hg) repo pull, Would it be better to just download latest stable?
-#ExternalProject_Add(EIGEN
-#	HG_REPOSITORY  "https://bitbucket.org/eigen/eigen/"
-#	UPDATE_COMMAND ""
-#	PATCH_COMMAND ""
-#    PREFIX ${CMAKE_CURRENT_BINARY_DIR}/external/eigen
-#    CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_INSTALL_PREFIX}
-#)
+if (HAVEHG)
+ExternalProject_Add(EIGEN
+	HG_REPOSITORY  "https://bitbucket.org/eigen/eigen/"
+	UPDATE_COMMAND ""
+	HG_TAG "default"
+    PREFIX ${CMAKE_CURRENT_BINARY_DIR}/external/eigen
+    CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_INSTALL_PREFIX}
+)
+ELSE() 
 # Stable Eigen, requires manual updating when new releases, but lighter weight.  
 ExternalProject_Add(EIGEN
 	URL "http://bitbucket.org/eigen/eigen/get/3.2.7.tar.gz"
+    #URL "http://bitbucket.org/eigen/eigen/get/default.tar.gz" # tip from repo
     PREFIX ${CMAKE_CURRENT_BINARY_DIR}/external/eigen
     CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_INSTALL_PREFIX}
 )
+ENDIF()
 
 # Yaml-cpp, this library is used extensively for serialisation of classes (class persistence) 
 ExternalProject_Add(YAML-CPP
 endif()
 
 # We don't build VTK, it is too heavy.
-option (LEMMA_VTK_SUPPORT "VTK library for visualisation and grids" OFF)
-if ( LEMMA_VTK_SUPPORT ) 
+option (LEMMA_VTK6_SUPPORT "VTK library for visualisation and grids" OFF)
+if ( LEMMA_VTK6_SUPPORT ) 
 	#find_package(VTK 6 REQUIRED NO_MODULE)
 	find_package(VTK 6.0 COMPONENTS vtkCommonCore vtkRenderingCore vtkFiltersCore vtkFiltersSources 
 			vtkCommonDataModel vtkFiltersHyperTree vtkIOXML vtkIOImage vtkIOLegacy vtkInteractionStyle 
 	include_directories ("${PROJECT_SOURCE_DIR}/Matplot_vtk")
 endif()
 
+option (LEMMA_VTK7_SUPPORT "VTK library for visualisation and grids" OFF)
+if ( LEMMA_VTK7_SUPPORT ) 
+	#find_package(VTK 7 REQUIRED NO_MODULE)
+	find_package(VTK 7.0 COMPONENTS vtkCommonCore vtkRenderingCore vtkFiltersCore vtkFiltersSources 
+			vtkCommonDataModel vtkFiltersHyperTree vtkIOXML vtkIOImage vtkIOLegacy vtkInteractionStyle 
+			vtkRenderingAnnotation vtkFiltersHybrid vtkFiltersModeling vtkRenderingVolumeOpenGL2 NO_MODULE)
+	set(volumeRenderer volumerenderer.cxx)
+	include(${VTK_USE_FILE}) 
+	add_compile_options(-DLEMMAUSEVTK) 
+	# Compile Matplot_vtk if VTK is present
+	add_subdirectory(Matplot_vtk)	
+	include_directories ("${PROJECT_SOURCE_DIR}/Matplot_vtk")
+endif()
+
 #####################
 # Lemma Configuration
 #####################

LemmaCore/CMakeLists.txt

 if (LEMMA_MATIO_SUPPORT)
 	add_dependencies(lemmacore MATIO)
 endif()
-if (LEMMA_VTK_SUPPORT) 
+
+if ( LEMMA_VTK6_SUPPORT OR LEMMA_VTK7_SUPPORT ) 
 	target_link_libraries(lemmacore ${VTK_LIBRARIES})
 	target_link_libraries(lemmacore "matplot")
 endif()
+
 target_link_libraries(lemmacore "yaml-cpp")
 
 # Install

LemmaCore/src/QWEKey.cpp

     //      Method:  GaussQuadWeights
     //--------------------------------------------------------------------------------------
     void QWEKey::GaussQuadWeights(const int& N) {
-        VectorXr Nv = VectorXr::LinSpaced(N-1, 1, N-1);
-        VectorXr beta  = 0.5 / (1.-(2.*Nv.array()).pow(-2)).sqrt();
-        MatrixXr T = MatrixXr::Zero(N,N);
-        //std::cerr << "Eigen ERROR BELOW, QWEKey.cpp  QWEKey::GaussQuadWeights, COMMENTED OUT ";
-        T.bottomLeftCorner(N-1, N-1) = beta.asDiagonal();
-        Eigen::SelfAdjointEigenSolver<MatrixXr> eig( T.selfadjointView< Eigen::Lower >() );
-            GaussAbscissa = eig.eigenvalues();
-            GaussWeights = 2.*eig.eigenvectors().row(0).array().pow(2);
+        std::cerr<<"QWEKey needs work to remove Boost, etc." << std::endl;
+        // Below works with older Eigen, need to find problem
+//         VectorXr Nv = VectorXr::LinSpaced(N-1, 1, N-1);
+//         VectorXr beta  = 0.5 / (1.-(2.*Nv.array()).pow(-2)).sqrt();
+//         MatrixXr T = MatrixXr::Zero(N,N);
+//         //std::cerr << "Eigen ERROR BELOW, QWEKey.cpp  QWEKey::GaussQuadWeights, COMMENTED OUT ";
+//         T.bottomLeftCorner(N-1, N-1) = beta.asDiagonal();
+//         Eigen::SelfAdjointEigenSolver<MatrixXr> eig( T.selfadjointView< Eigen::Lower >() ); // PROBLEM LINE
+//             GaussAbscissa = eig.eigenvalues();
+//             GaussWeights = 2.*eig.eigenvectors().row(0).array().pow(2);
     }
 
     //--------------------------------------------------------------------------------------