Function noll_to_ansi 

pub const fn noll_to_ansi(j: u32) -> u32

The ANSI index of the mode carrying Noll index j.

The gather a Noll-indexed caller needs against an ANSI-laid-out basis buffer, which is what zernike_basis fills. Exists as one function because the composition ansi_index(noll_to_nm(j)) is short enough to write by hand at every call site and exactly the kind of thing that gets written backwards.

Panics

If j is zero. Noll indices start at 1.