On Thu, 21 Jul 2022 17:56:45 -0400
John Kitzmiller <jkitzm@gmail.com> wrote:

> (Apologies for double-dipping, but usage direction for the
> least-squares fit extension in m-graph would be a gift.)

The least-squares fit (to a polynomial) is a deterministic calculation,
not an arbitrary non-linear search. As such, it is very robust.

Certain (useful) functions, a Gaussian peak for example, can be
suitably transformed to a polynomial function, so these are handled as
well, robustly.

Examples are given as comments in mp-grap.mpiv that you can follow.
Also attached is an adapted version of the original John Hobby
documentation, with extensions described.

Note that the m-graph module is simply a re-write of the John Hobby
graph macros, taking advantage of floating-point MetaPost (thus
simplified).

%%%%%%%%%%%%%%%%%%%%%%%%

I have been working on a completely new luagraph module that does much
in lua. It has, notably, arbitrary coordinate systems.

This has been a moving target as I put more and more into lua
and less and less in Metapost. I have also been playing chase with the
development of luametatex (and have fallen behind).

Alan