anchor.diff:          t_self_images = any(abs(box_length-1.0_dp) < depsilon)
   
           allocate(tmat(basis_length,nbasis), stat=ierr)
  +        allocate(connected_orbs(basis_length,nbasis), stat=ierr)
   
           tmat = 0
   
  
positive.code: ! where a site is connected to a different site and that site's periodic image.
  integer(i0), allocatable :: tmat(:,:) ! (basis_length, nbasis)
  
  ! True if any site is its own periodic image.
  ! This is the case if one dimension (or more) has only one site per crystal
  ! cell.  If so then the an orbital can incur a kinetic interaction with itself.
  
negative.code:                     end if
                  end do
              end do
          end do
  
          ! Information for the random excitation generators.
          connected_orbs = tmat
          do i = 1, nbasis
              pos = bit_lookup(1,i)
              ind = bit_lookup(2,i)
              connected_orbs(ind,i) = ibclr(connected_orbs(ind,i),pos)
          end do
  
      end subroutine init_real_space_hub
  