(self)
return self._rank_binary
Computes the binary ordered rank.

        Examples
        ========

        >>> from sympy.combinatorics.subsets import Subset
        >>> a = Subset([], ['a','b','c','d'])
        >>> a.rank_binary
        0
        >>> a = Subset(['c','d'], ['a','b','c','d'])
        >>> a.rank_binary
        3

        See Also
        ========
        iterate_binary, unrank_binary
Computes the binary ordered rank.
Computes the binary ordered rank .
def rank_binary(self):
        """
        Computes the binary ordered rank.

        Examples
        ========

        >>> from sympy.combinatorics.subsets import Subset
        >>> a = Subset([], ['a','b','c','d'])
        >>> a.rank_binary
        0
        >>> a = Subset(['c','d'], ['a','b','c','d'])
        >>> a.rank_binary
        3

        See Also
        ========
        iterate_binary, unrank_binary
        """
        if self._rank_binary is None:
            self._rank_binary = int("".join(
                Subset.bitlist_from_subset(self.subset,
                                           self.superset)), 2)
        return self._rank_binary
def rank_binary ( self ) : if self . _rank_binary is None : self . _rank_binary = int ( "" . join ( Subset . bitlist_from_subset ( self . subset , self . superset ) ) , 2 ) return self . _rank_binary