Figure 6.

The error of reconstruction Δ_ψ, Eq. (12), with respect to the inclination of the Poincaré surface of section α, and its relative position θ, see Methods for definition. In (a) the white regions correspond to error values out of range ${\mathrm{\Delta }}_{\psi }>0.06$. The particular values marked with colored circles correspond to example surfaces of section plotted in (b) with lines of the same color. The red (Δ_ψ = 0.0045), green (Δ_ψ = 0.0051), yellow (Δ_ψ = 0.0049) and orange (Δ_ψ = 0.0051) sections yield good period determination: the error is low and in (b) we see that they have a similar inclination to the local isochrones, plotted with thin gray curves. The blue one (Δ_ψ = 0.054) is an example of an inaccurate surface of section that does not correspond to local isochrones (see (b)) and therefore yields a high error. Notice that the yellow line corresponds to the optimal section in Fig. 5. The search was performed using a single simulation run of length t_sim = 500 (corresponding to roughly 500 periods). Parameters are $\epsilon \parallel Z\parallel =1$ and τ = 0.1.