Validation of the implementation of angle-dependent SIDM using the explicit sampling technique to determine the deflection angles from the underlying differential cross section (anisotropic rSIDM scheme). We show the angular distribution function f(t, θ)⋅sin(θ) of beam particles within the deflection test set-up for three different times t (solid lines) in units of the reference time t₁ (see main text), and compare to the exact analytical solution for multiple scatterings in a target given in Eq. (18) (dashed lines). The lower panel shows the difference, normalised to the statistical error. Here we assume the ‘Rutherford’ cross section given in Eq. (2) with r = 10⁴, and beam-target scattering without recoil. For illustration, also the isotropic distribution f_∞ = 1/2 is shown (dotted) that, as we checked, is approached for t ≫ t₁ (we note that the x-axis range extends only up to θ ≤ 0.6 ≃ π/5).