[Gretl-devel] Re: Another extra.gfn candidate?

On Mon, 20 May 2019, Allin Cottrell wrote: > On Mon, 20 May 2019, Riccardo (Jack) Lucchetti wrote: > > > Sorry for the bombardment: I just realised that, much to my surprise, not > > only > > we don't have a numerical root-finding function in hansl; it seems we > > don't > > have one in libgretl either! > > > > So I put together a quick hansl prototype for the crudest algorithm there > > is > > (the bisection method). It's reportd below, with a few examples. The > > question > > is very much similar to the one in the other thread: shall we put this > > into > > extra.gfn, or add this (hopefully, in a refined form) to libgretl and > > eventually expose a user-level function? > > The prototype seems to work very nicely. I've added a C translation as > a hansl built-in under the name fzero (might as well use the matlab > name, I guess). Not yet documented. Wow, very nice, thanks! I was thinking that perhaps we may want to change the signature of the function a little to make it more flexible: how about modelling it after GSSmax (with the obvious adjustments)? That way, one could easily solve for a function with parameters.