def n_angles(theta1_min: float, theta1_max: float, theta1_step=1) -> int:
    """
    Computes number of traces for given angles on incidence.

    :param theta1_min: minimum incidence angle
    :param theta1_max: maximum incidence angle
    :param theta1_step: angle of incidence steps, default is 1
    :return:
        n_trace: number of traces
    """
    n_trace = int((theta1_max - theta1_min) / theta1_step + 1)
    return n_trace