def make_ring_grad_line(xt, yt, dt, i_deg, phi_deg):
    yy = np.ones_like(xt) * yt
    xx = xt - dt

    aa = np.vstack((yy, xx))

    (ellipse, gradient) = ellipse_nest(aa, i_deg, phi_deg)

    # convert gradient to abs projected along x-axis
    grad_disk = np.abs(np.sin(gradient))

    return(ellipse, grad_disk)
Creates a ``QuerySet`` containing root nodes.
dataset/ETHPy150Open mkenworthy/exorings/exorings.py/make_ring_grad_line--crossover with--dataset/ETHPy150Open django-mptt/django-mptt/mptt/managers.py/TreeManager.root_nodes