From: Joel VanderWerf <joelvanderwerf@...>
Date: 2011-05-06T07:24:23+09:00
Subject: Re: native ruby Levenberg–Marquardt (or other curve fitting)

On 05/05/2011 02:44 PM, Fearless Fool wrote:
> Sooner or later, my Rails app will need a good curve fitting algorithm
> -- I've used Levenberg–Marquardt in the past and know it works well for
> my needs.  There's even a nice set of Ruby bindings to the Gnu
> Scientific Library (GSL) package, which has an implementation of
> Levenberg–Marquardt.
>
> But.  My app will be hosted on Heroku, and Heroku doesn't include GSL in
> its stack.  Ergo, I need a native implementation of Levenberg–Marquardt
> (or other curve fitting algorithm).
>
> Does anyone know of a solid curve fitting algorithm implemented in
> native Ruby, preferably available as a gem?

Heroku does support gems with extensions, so what about ripping out the 
parts of gsl that you need, wrapping them in a little ruby ext (perhaps 
a simplified form of the gsl gem itself), and packaging that as a gem? 
This is sort of the amalgalite approach.

The work involve might be worth keeping the same library and api that 
you are used to.