anchor.diff:    print *,  trim(output(2))
   
   end
  -
  -subroutine print_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_str( output(1), string(1,1), Nint )
  -  call bitstring_to_str( output(2), string(1,2), Nint )
  -  print *,  trim(output(1))
  -  print *,  trim(output(2))
  -
  -end
  
positive.code: subroutine list_to_bitstring( string, list, n_elements, Nint)
    use bitmasks
    implicit none
    integer, intent(in)            :: Nint
    integer(bit_kind), intent(out) :: string(Nint)
    integer, intent(in)            :: list(Nint*bit_kind_size)
  
negative.code:   
    integer                        :: i, j
    integer                        :: ipos, iint
  
    ! 
    !                                       <== ipos ==>
  