Function batch_add_assign_no_branch 

fn batch_add_assign_no_branch<P: SWCurveConfig>(
    denominators: &mut [P::BaseField],
    v0: &mut [Affine<P>],
    v1: &[Affine<P>],
)

Given arrays of curve points v0 and v1 do v0[i] += v1[i] for each i, assuming that for each i, v0[i].x != v1[i].x so we can use the ordinary addition formula and don’t have to handle the edge cases of doubling and hitting the point at infinity.