Provides the reaction energy of a stable entry from the neighboring
        equilibrium stable entries (also known as the inverse distance to
        hull).

        Args:
            entry: A PDEntry like object

        Returns:
            Equilibrium reaction energy of entry. Stable entries should have
            equilibrium reaction energy <= 0.

def get_equilibrium_reaction_energy(self, entry):
        """
        Provides the reaction energy of a stable entry from the neighboring
        equilibrium stable entries (also known as the inverse distance to
        hull).

        Args:
            entry: A PDEntry like object

        Returns:
            Equilibrium reaction energy of entry. Stable entries should have
            equilibrium reaction energy <= 0.
        """
        if entry not in self.stable_entries:
            raise ValueError("Equilibrium reaction energy is available only "
                             "for stable entries.")
        if entry.is_element:
            return 0
        entries = [e for e in self.stable_entries if e != entry]
        modpd = PhaseDiagram(entries, self.elements)
        return modpd.get_decomp_and_e_above_hull(entry,
                                                 allow_negative=True)[1]