Returns the percentage lattice parameter changes.

        Returns:
            A dict of the percentage change in lattice parameter, e.g.,
            {'a': 0.012, 'b': 0.021, 'c': -0.031} implies a change of 1.2%,
            2.1% and -3.1% in the a, b and c lattice parameters respectively.

def get_percentage_lattice_parameter_changes(self):
        """
        Returns the percentage lattice parameter changes.

        Returns:
            A dict of the percentage change in lattice parameter, e.g.,
            {'a': 0.012, 'b': 0.021, 'c': -0.031} implies a change of 1.2%,
            2.1% and -3.1% in the a, b and c lattice parameters respectively.
        """
        initial_latt = self.initial.lattice
        final_latt = self.final.lattice
        d = {l: getattr(final_latt, l) / getattr(initial_latt, l) - 1
             for l in ["a", "b", "c"]}
        return d