Roberto, ECJ doesn't have the equivalent of a .fn file, but it *does* have a few facilities that might be of use to you. 1. ECJ can write out the expression in a syntax which, with a few tweaks, compiles as C. See section 5.2.8.1 of the ECJ Owner's Manual. 2. The file ec/app/regression/convertToMathematica.lisp has a small lisp file which can convert ECJ's symbolic regression individuals into Mathematica expressions which are nicely graphed. Sorry for the late response: I was away. Sean On Jun 8, 2011, at 9:31 AM, Roberto Oliveira Santos wrote: > Hello, > > I'm running tutorial 4 and would like to generate a .fn file like > lil-gp, so > I could plot a chart of my original function against the function > generated > by my best individual. > > Kind regards, > > Roberto