Comments for future consideration/improved usability:

angle is a little clunky, it would be nice if it were auto-computed and stored within the Bounce2D functional or within the objective,
    maybe it is fine for the objective part, but when I compute a quantity outside of an objective it is unintuitive to compute angle first, separately. if angle is nonexistent it should be computed automatically, perhaps inside the Bounce2D creation...

Originally posted by @dpanici

Reply by @unalmis :
Ideally, it would be computable quantity in data_index and in Bounce2D.required_names. Then users can change this code:

from desc.integrals import Bounce2D

angle = Bounce2D.angle(eq, rho=grid.compress(grid.nodes[: ,0]))
datas = eq.compute("effective ripple", grid=grid, angle=angle)

to

datas = eq.compute("effective ripple", grid=grid)