def automatic_density(structure, kppa, force_gamma=False):
        """
        Returns an automatic Kpoint object based on a structure and a kpoint
        density. Uses Gamma centered meshes for hexagonal cells and
        Monkhorst-Pack grids otherwise.

        Algorithm:
            Uses a simple approach scaling the number of divisions along each
            reciprocal lattice vector proportional to its length.

        Args:
            structure (Structure): Input structure
            kppa (int): Grid density
            force_gamma (bool): Force a gamma centered mesh (default is to
                use gamma only for hexagonal cells or odd meshes)

        Returns:
            Kpoints
        """
        comment = "pymatgen v%s with grid density = %.0f / atom" % (
            __version__, kppa)
        if math.fabs((math.floor(kppa ** (1 / 3) + 0.5)) ** 3 - kppa) < 1:
            kppa += kppa * 0.01
        latt = structure.lattice
        lengths = latt.abc
        ngrid = kppa / structure.num_sites
        mult = (ngrid * lengths[0] * lengths[1] * lengths[2]) ** (1 / 3)

        num_div = [int(math.floor(max(mult / l, 1))) for l in lengths]

        is_hexagonal = latt.is_hexagonal()

        has_odd = any([i % 2 == 1 for i in num_div])
        if has_odd or is_hexagonal or force_gamma:
            style = Kpoints.supported_modes.Gamma
        else:
            style = Kpoints.supported_modes.Monkhorst

        return Kpoints(comment, 0, style, [num_div], [0, 0, 0])
Returns an automatic Kpoint object based on a structure and a kpoint
        density. Uses Gamma centered meshes for hexagonal cells and
        Monkhorst-Pack grids otherwise.

        Algorithm:
            Uses a simple approach scaling the number of divisions along each
            reciprocal lattice vector proportional to its length.

        Args:
            structure (Structure): Input structure
            kppa (int): Grid density
            force_gamma (bool): Force a gamma centered mesh (default is to
                use gamma only for hexagonal cells or odd meshes)

        Returns:
            Kpoints