Get all near-neighbor sites as well as the associated image locations
        and weights of the site with index n using the closest relative
        neighbor distance-based method with VIRE atomic/ionic radii.

        Args:
            structure (Structure): input structure.
            n (integer): index of site for which to determine near
                neighbors.

        Returns:
            siw (list of tuples (Site, array, float)): tuples, each one
                of which represents a neighbor site, its image location,
                and its weight.

def get_nn_info(self, structure, n):
        """
        Get all near-neighbor sites as well as the associated image locations
        and weights of the site with index n using the closest relative
        neighbor distance-based method with VIRE atomic/ionic radii.

        Args:
            structure (Structure): input structure.
            n (integer): index of site for which to determine near
                neighbors.

        Returns:
            siw (list of tuples (Site, array, float)): tuples, each one
                of which represents a neighbor site, its image location,
                and its weight.
        """

        vire = ValenceIonicRadiusEvaluator(structure)
        site = vire.structure[n]
        neighs_dists = vire.structure.get_neighbors(site, self.cutoff)
        rn = vire.radii[vire.structure[n].species_string]

        reldists_neighs = []
        for neigh, dist in neighs_dists:
            reldists_neighs.append([dist / (
                    vire.radii[neigh.species_string] + rn), neigh])

        siw = []
        min_reldist = min([reldist for reldist, neigh in reldists_neighs])
        for reldist, s in reldists_neighs:
            if reldist < (1.0 + self.tol) * min_reldist:
                w = min_reldist / reldist
                siw.append({'site': s,
                            'image': self._get_image(vire.structure, s),
                            'weight': w,
                            'site_index': self._get_original_site(
                                vire.structure, s)})

        return siw