[R] arima/fixed

[Martin Maechler]

>>>>> Martin Maechler 
>>>>>     on Sat, 30 Jan 2021 12:21:14 +0100 writes:

>>>>> Rolf Turner 
>>>>>     on Sat, 30 Jan 2021 16:11:32 +1300 writes:

    >> On Fri, 29 Jan 2021 12:47:25 +0000 Nasia Petsa
    >> <petsa.athanasia using hotmail.gr> wrote:

    >>> Dear all,
    >>> 
    >>> I have the following problem with determining the
    >>> argument fixed in arima function. What is the length of
    >>> argument fixed for an ARIMA(1,0,0)(0,1,1) and what is
    >>> the correct order for the parameters

    >> Hmm.  The help is indeed pretty opaque, isn't it?

    > Can you propose improvements?

    > Here(*) is the source code of the help page

    >   http://svn.r-project.org/R/trunk/src/library/stats/man/arima.Rd

    > We (and future R users) would be glad for less opaque (and
    > still concise) wording, notably in simple enough English
    > for the 90% non-natively English speaking R users ..

    > Thank you in advance!  Martin

In the mean time, Rolf sent me a nicely enhanced arima.Rd
which is now part of R  (R-devel at least):

------------------------------------------------------------------------
r79918 | maechler | 2021-02-01 15:07:32 +0100 (Mon, 01 Feb 2021) | 1 line
Changed paths:
   M src/library/stats/man/arima.Rd
   M tests/Examples/stats-Ex.Rout.save

extended for `fixed` arg, plus ex., thanks to Rolf Turner
------------------------------------------------------------------------

(Unfortunately, I added 1 stray character when slightly editing
 Rolf's version.)

Such _careful_ contributions are welcome, thank you again!

---
Martin