anchor.diff:          integer :: i
    
           do i = 1, ncol
  +            ! y = H x,
  +            ! where H is the Hamiltonian matrix, x is the input Lanczos vector
  +            ! and y the output Lanczos vector.
               call dsymv('U', nrow, 1.0_dp, hamil, nrow, xin(:,i), 1, 0.0_dp, yout(:,i), 1)
           end do
    
  
positive.code:         hmatel = 0.0_dp
  
          select case(excitation%nexcit)
          case(0)
  
              root_det = decode_det(root_det_f)
  
              ! One electron operator
              do i = 1, nel
  
negative.code: 
          case(2)
  
              ! < D | H | D_{ij}^{ab} > = < ij || ab >
  
              ! Two electron operator
              hmatel = get_two_e_int(excitation%from_orb(1), excitation%from_orb(2), excitation%to_orb(1), excitation%to_orb(2))
  
  