def stub(self):
        files = shell_exec("ls dirs").split('\n')
        files = map(lambda x: x.replace('dir_', ''), files)
        fc2 = readfc2('fc2')
        for file in files:
            ref = io.read('SPOSCAR')
            a = 'dirs/dir_' + str(file)
            atoms = io.read(a + "/POSCAR")
            u = atoms.positions - ref.positions
            f = -np.einsum('ijkl,jl', fc2, u)
            forces = ""
            for force in f:
                forces += "<v>  %f %f %f </v>\n" % tuple(force)
            vasprun = '<root><calculation><varray name="forces" >\n'
            vasprun += forces
            vasprun += '</varray></calculation></root>\n'
            write(vasprun, a + "/vasprun.xml")