anchor.diff:                      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
  
positive.code:         t_self_images = any(abs(box_length-1.0_dp) < depsilon)
  
          allocate(tmat(basis_length,nbasis), stat=ierr)
  
          tmat = 0
  
  
negative.code: ! where a site is connected to a different site and that site's periodic image.
  integer(i0), allocatable :: tmat(:,:) ! (basis_length, nbasis)
  
  ! Identical to tmat but without a bit set for an site being its own
  ! periodic image.  This is useful in FCIQMC for generating random
  ! excitations.
  integer(i0), allocatable :: connected_orbs(:,:) ! (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.
  