(a) Collection of s pieces exceeding a chosen threshold d (here s = 12 and d = 0.2; see Text ). The green line is the “true” functional representation of X2 versus v3. (b) Pairs in (a) are merged based on their distances and on the distances between two points in a pair. (c) The subgroups of pairs in (b) are merged. (d) The sigmoidal shape of points in (c) suggests that the flux of the smallest X2 (~0.25) should be close to zero. The sum of errors between the estimated points and their corresponding true values (on the green line) is 0.0551.