data fitting

[Stefano Ghirlanda]

Hi,
I'd like to know if there are any functions to fit a user-defined function
to a set of data. I've been looking to the manual but didn't find it.
Now I use the fit command in gnuplot, do you know how reliable it is?
I'd also like to know if you use any software for such problems.

Thanks to everyone, octave is very useful.

Stefano Ghirlanda, Zoologiska Institutionen, Stockholms Universitet
Office: Frescati Campus, Hus D, Rum 554. Office Phone: +46-8-164055
Mail: Svante Arrheniusv. 14, S-106 91, Stockholm, Sweden           
E-mail: address@hidden, Web: http://rerumnatura.zool.su.se