From: Borries Demeler <demeler@bioc09.v19.uthscsa.edu>
  To  : R Mullins <dyche@itsa.ucsf.edu>
  Date: Wed, 11 Apr 2001 15:51:03 -0500 (CDT)

Re: global nonlinear fitting

> 
> 
> Does anybody know of a good, inexpensive software package to do 
> global, nonlinear least squares fitting for systems of ordinary
> differential equations? We have been using KINSIM and FITSIM for 
> years but now I think it's time to move on. FITSIM doesn't have 
> the world's most user frienldy interface and isn't very numerically
> stable, especially when fitting multiple parameters. Our preferred
> operating system is LINUX. 
> 

I have written a global nonlinear least squares fitting engine with 
GUI wrapper for Unix/X, it incorporates 3 different NLS algorithms,
incl. Gauss Newton and Levenberg Marquardt. There aren't any memory
limitations. The problem is only that you would need some C++ knowledge
to adapt it to your needs. You will also have to write the objective
function and it's jacobian, since all derivatives are calculated 
analytically or with automatic differentiation for non-explicit functions.
I have a version that comes with a global example and an example with a
numerical solution for the objective function (finite element solution
of the Lamm equation).

I'd be happy to share it with you if it were helpful. BTW, it is based on
QT and QWT for the GUI part.

But maybe you are looking for something a bit more refined, in that case
take a look at octave or scilab. It allows you to write scripts similar
to Matlab. Both are free for Linux/Unix. You can find them on freshmeat.net
or on SAL: http://ftp.llp.fu-berlin.de/lsoft/index.shtml


Hope that helps, -Borries