pub fn true_point_fractions(i: usize, intervals: usize) -> &'static [(i64, i64)]Expand description
Where, within interval i of intervals between consecutive samples, a
caller of interpolate_enclosing should locate its true points: these
fractions of the way from one sample to the next.
One point, in the middle, for an interior interval — that is where a cubic interpolant’s drift peaks, and it keeps the extra work at one projection per interval. The two end intervals get three: next to a clamped end the drift is lopsided, and on a circle sampled in 8 intervals a single midpoint there left a true point unenclosed.