import guan import numpy as np k_array = np.linspace(-np.pi, np.pi, 100) eigenvalue_array = guan.calculate_eigenvalue_with_one_parameter(k_array, guan.hamiltonian_of_square_lattice_in_quasi_one_dimension) guan.plot(k_array, eigenvalue_array, xlabel='k', ylabel='E', type='-k') eigenvalue_array = guan.calculate_eigenvalue_with_one_parameter(k_array, guan.hamiltonian_of_graphene_with_zigzag_in_quasi_one_dimension) guan.plot(k_array, eigenvalue_array, xlabel='k', ylabel='E', type='-k')