Generates the opposite number of energy above grand potential
        convex hull for both reactants.

        Returns:
            [(reactant1, no_mixing_energy1),(reactant2,no_mixing_energy2)].

def get_no_mixing_energy(self):
        """
        Generates the opposite number of energy above grand potential
        convex hull for both reactants.

        Returns:
            [(reactant1, no_mixing_energy1),(reactant2,no_mixing_energy2)].
        """
        assert self.grand == 1, \
            'Please provide grand potential phase diagram ' \
            'for computing no_mixing_energy!'

        energy1 = self.pd.get_hull_energy(self.comp1) - \
            self._get_grand_potential(self.c1)
        energy2 = self.pd.get_hull_energy(self.comp2) - \
            self._get_grand_potential(self.c2)
        unit = 'eV/f.u.'
        if self.norm:
            unit = 'eV/atom'
        return [(self.c1_original.reduced_formula +
                 ' ({0})'.format(unit), energy1),
                (self.c2_original.reduced_formula +
                 ' ({0})'.format(unit), energy2)]