def drawDos(self):
        freq, pdos = self.getpdos()
        datas = [(freq, p, '') for p in pdos.T]
        series(
            'Frequency (THz)',
            'Partial Density of States',
            datas=datas,
            filename='partial_dos.png',
            legend=False,
            grid=True)

        plot(
            (freq, 'Frequency (THz)'), (np.sum(pdos, axis=1),
                                        'Density of States'),
            filename='total_dos.png')
        # calculate paticipation ratio