def chebyshev_recurrence(t_k_minus_one, t_k_minus_two, scaled_lap):
    s_lap = sp.csr_matrix(scaled_lap, copy=True)
    return ((2 * s_lap.dot(t_k_minus_one)) - t_k_minus_two)
def chebyshev_recurrence(t_k_minus_one, t_k_minus_two, scaled_lap):
    s_lap = sp.csr_matrix(scaled_lap, copy=True)
    return ((2 * s_lap.dot(t_k_minus_one)) - t_k_minus_two)