Re: [Gretl-users] One-sided HP filter

Am 08.03.2018 um 16:19 schrieb Riccardo (Jack) Lucchetti: > However, I'd like to ask the community a question: how should we use this: > I have three possibilities: ... > > * implement this as a variant of our native hpfilt() function, with an > extra boolean flag for one-sidedness. This one makes the most sense IMHO.

(Additional remark: hpfilt already has another optional scalar parameter. If I understand correctly, if a built-in function has an optional string parameter, then in the next gretl release it would be possible to skip the numerical optional arguments. So if the one-sided option is implemented as a string, it would be possible to write something like hpfilt(y, "1side"). Don't know if that convenience is enough to replace a plain boolean 0-1 argument...)