Re: [Gretl-devel] unitdum: link to nowhere in the guide
Am 24.09.2018 um 23:38 schrieb Allin Cottrell:
On Mon, 24 Sep 2018, Sven Schreiber wrote:
> in ch. 20 it says: "(See Chapter 9 for details on unitdum)." but
> there is nothing there in ch. 9. This is the concrete buglet there.
>
With my suggestion below, this problem would be solved by adding the
missing material in ch.9.
Well, that would leave chapter 9 as about one paragraph! I'm
happy to
accept any suggestions for redistributing the useful material in the
present ch 9, after which we could cut it out.
OK, here are my suggestions:
- lrvar (9.2) -> move to function ref, or to the "time series filters"
or "univariate time series models" chapters
- cdf and pvalue details (9.3) : -> either also move to function ref, or
to the "cheatsheet" chapter
- $test and $pvalue details (9.4) -> could stay in that chapter (but
would add a further note about "genr" and why most of the time you
shouldn't use it)
- Fourier transform (9.5): move to function ref or to "numerical methods"
- If ch. 9 stays (for example using the current 9.4 from above), then
also add: genr unitdum, genr timedum, genr time, genr index, genr dummy,
until they are obsoleted. But see below.
As for the actual "genr" specials, I think the "genr" entry in the
Command Reference would be the right place for them. But that too
wants some re-working in the light of the last decade's development of
gretl. I mean something along the lines of "Look, this is legacy
stuff, but just in case you want it, or come across it...".
As long as the specials exist, I think it's not bad to have them in the
guide. (I could write something about it late next week, if wanted.) But
I would also be OK to move them to the command ref.
Let me recap the situation with the genr specials:
- genr time: Can already be avoided with "series x = time". (Same with
'index'.) For consistency with the rest of gretl I suggest to introduce
an alias '$time' for 'time' such that "series x = $time" becomes
possible.
- genr unitdum: Can in principle be avoided with: "list D =
dummify($unit, NA)". However, this fails when many units are in the
panel, in which case one has to do:
<hansl>
series u = $unit
discrete u
list Du = dummify(u, NA)
</hansl>
One possibility would be to add an equivalent function unitdum() to the
'extra' addon, such that "list Du = unitdum()" would work (after
"include extra.gfn"), possibly with an optional string argument to
affect the naming of the dummies.
The other option is a native new '$unitdum' which returns such a list.
- genr timedum: Already possible with "list Td = dummify(time, NA)".
Again having $time would be nice. Also for long panels with large T
dimension the same caveat as with unitdum may apply. By analogy a
timedum() function in 'extra' or a native $timedum are options.
- genr dummy: Can already be avoided with "list S = seasonals()".
Perhaps a new optional string arg to affect the naming could be useful
as well (but not very important of course).
Any other genr special that I'm forgetting?
thanks,
sven