• EIGEN_YES_I_KNOW_SPARSE_MODULE_IS_NOT_STABLE_YET : gp_regression.cpp
• NORM : data_extractor.cpp , force_labeler.cpp
• NORMAL : force_labeler.cpp , data_extractor.cpp , project_pc_ellipsoid.cpp
• PI : ellipsoid_space.h
• SE : density_estimation.cpp , gp_regression.cpp
• SQ : ellipsoid_space.h , data_extractor.cpp