Hi all, I'd just like to tell people that we have a new function package (by yours truly) called "basis_functions", that can be used for easily incorporating nonlinearity in your models; it also includes a handy function for generating Fourier harmonics. You can find it in the usual place: http://gretl.sourceforge.net/cgi-bin/gretldata.cgi?opt=SHOW_FUNCS Of course, comments are welcome. ------------------------------------------------------- Riccardo (Jack) Lucchetti Dipartimento di Scienze Economiche e Sociali (DiSES) Università Politecnica delle Marche (formerly known as Università di Ancona) r.lucchetti(a)univpm.it http://www2.econ.univpm.it/servizi/hpp/lucchetti -------------------------------------------------------