51   H_sqr.col(0) = (1./16.) * (4. * L.col(3).array().square() * L.col(0).array().square() -   in dihedral_angles_intrinsic()
52                                 ((L.col(1).array().square() + L.col(4).array().square()) -  in dihedral_angles_intrinsic()
53                                  (L.col(2).array().square() + L.col(5).array().square())).square());  in dihedral_angles_intrinsic()
54   H_sqr.col(1) = (1./16.) * (4. * L.col(4).array().square() * L.col(1).array().square() -   in dihedral_angles_intrinsic()
55                                 ((L.col(2).array().square() + L.col(5).array().square()) -  in dihedral_angles_intrinsic()
56                                  (L.col(3).array().square() + L.col(0).array().square())).square());  in dihedral_angles_intrinsic()
57   H_sqr.col(2) = (1./16.) * (4. * L.col(5).array().square() * L.col(2).array().square() -   in dihedral_angles_intrinsic()
58                                 ((L.col(3).array().square() + L.col(0).array().square()) -  in dihedral_angles_intrinsic()
59                                  (L.col(4).array().square() + L.col(1).array().square())).square());  in dihedral_angles_intrinsic()
60   H_sqr.col(3) = (1./16.) * (4. * L.col(0).array().square() * L.col(3).array().square() -   in dihedral_angles_intrinsic()
61                                 ((L.col(4).array().square() + L.col(1).array().square()) -  in dihedral_angles_intrinsic()
62                                  (L.col(5).array().square() + L.col(2).array().square())).square());  in dihedral_angles_intrinsic()
63   H_sqr.col(4) = (1./16.) * (4. * L.col(1).array().square() * L.col(4).array().square() -   in dihedral_angles_intrinsic()
64                                 ((L.col(5).array().square() + L.col(2).array().square()) -  in dihedral_angles_intrinsic()
65                                  (L.col(0).array().square() + L.col(3).array().square())).square());  in dihedral_angles_intrinsic()
66   H_sqr.col(5) = (1./16.) * (4. * L.col(2).array().square() * L.col(5).array().square() -   in dihedral_angles_intrinsic()
67                                 ((L.col(0).array().square() + L.col(3).array().square()) -  in dihedral_angles_intrinsic()
68                                  (L.col(1).array().square() + L.col(4).array().square())).square());  in dihedral_angles_intrinsic()
71       A.col(1).array().square() - A.col(2).array().square()).array() /   in dihedral_angles_intrinsic()
74       A.col(2).array().square() - A.col(0).array().square()).array() /   in dihedral_angles_intrinsic()
77       A.col(0).array().square() - A.col(1).array().square()).array() /   in dihedral_angles_intrinsic()
80       A.col(3).array().square() - A.col(0).array().square()).array() /   in dihedral_angles_intrinsic()
83       A.col(3).array().square() - A.col(1).array().square()).array() /   in dihedral_angles_intrinsic()
86       A.col(3).array().square() - A.col(2).array().square()).array() /   in dihedral_angles_intrinsic()