pub fn stretch_tab() -> &'static Vec<i32>
Inverse of sig16 on a p >> 4 grid: the smallest Q8 z with sig16(z) ≥ p (p = 16·i + 8), so stretch(p) ∈ [−ZM, ZM].
sig16
p >> 4
z
sig16(z) ≥ p
p = 16·i + 8
stretch(p) ∈ [−ZM, ZM]