Sooner or later, my Rails app will need a good curve fitting algorithm
-- I've used LevenbergMarquardt 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
LevenbergMarquardt.

But.  My app will be hosted on Heroku, and Heroku doesn't include GSL in
its stack.  Ergo, I need a native implementation of LevenbergMarquardt
(or other curve fitting algorithm).

Does anyone know of a solid curve fitting algorithm implemented in
native Ruby, preferably available as a gem?

TIA.

- ff