anchor.diff:    
     integer                        :: i, j
     integer                        :: ipos, iint
  -  BEGIN_DOC
  -  ! Returnd the physical string "string(N_int,2)" from the array of
  -  ! occupations "list(N_int*bit_kind_size,2)
  -  END_DOC
   
     ! 
     !                                       <== ipos ==>
  
positive.code: subroutine debug_det(string,Nint)
    use bitmasks
    implicit none
    integer, intent(in) :: Nint
    integer(bit_kind), intent(in) :: string(Nint,2)
    character*(512) :: output(2)
    call bitstring_to_hexa( output(1), string(1,1), Nint )
    call bitstring_to_hexa( output(2), string(1,2), Nint )
    print *,  trim(output(1)) , '|', trim(output(2))
  
    call bitstring_to_str( output(1), string(1,1), Nint )
    call bitstring_to_str( output(2), string(1,2), Nint )
  
negative.code:   print *,  trim(output(2))
  
  end
  