anchor.diff:  
       end function decode_det
   
  -    pure subroutine decode_det_occ_spinunocc(f, occ_list, unocc_list_alpha, unocc_list_beta)
  +    pure subroutine decode_det_occ_spinunocc(f, d)
   
           ! Decode determinant bit string into integer lists containing the
           ! occupied and unoccupied orbitals.  The unoccupied alpha and beta
  
positive.code:             do j = 0, i0_end
                  if (btest(f(i), j)) then
                      iocc = iocc + 1
                      occ_list(iocc) = basis_lookup(j, i)
                  else
                      if (mod(j,2)==0) then
                          ! alpha state
                          iunocc_a = iunocc_a + 1
                          unocc_list_alpha(iunocc_a) = basis_lookup(j, i)
                      else
                          ! beta state 
                          iunocc_b = iunocc_b + 1
                          unocc_list_beta(iunocc_b) = basis_lookup(j, i)
                      end if
                  end if
                  ! Have we covered all basis functions?
  
negative.code: 
      end subroutine decode_det_occ_spinunocc
  
      pure subroutine decode_det_spinocc_spinunocc(f, d)
  
          ! Decode determinant bit string into integer lists containing the
          ! occupied and unoccupied orbitals.  
  