Typo/bug in ar.yw.default, ar.ols, ar.burg.default

Simone Giannerini 
    on Thu, 12 Mar 2026 18:17:53 +0100 writes:

> Dear Martin,
    > thanks for the reply,

    > the instruction after the bugged line of code is

    > xaic <- setNames(if(is.finite(maic)) xaic - min(xaic) else
    > ifelse(xaic == maic, 0, Inf), 0L:order.max)

    > and checks whether  is.finite(maic), which, in the present version, is
    > always the case since maic is either 0 or 1.
    > But if min(xaic) is truly not finite, say, NA, then  xaic - min(xaic) will
    > also be a vector of NAs, which is not the intended output, so to me this
    > looks like a bug.

    > Kind regards,

    > Simone

I wrote my reply before yours yesterday, but did only get to
send it off now (~ 20 min ago).
I see you came to the same conclusion.

Martin


    > On Thu, Mar 12, 2026 at 12:12?PM Martin Maechler <maechler at stat.math.ethz.ch>

>> >>>>> Simone Giannerini
    >> >>>>>     on Mon, 9 Mar 2026 12:43:07 +0100 writes:
    >> 
    >> > Dear all,
    >> > I think there is a (small) bug in
    >> 
    >> > ar.yw.default   (line 142 of the source file ar.R)
    >> > ar.ols          (line 429 of the source file ar.R)
    >> > ar.burg.default (line 570 of the source file ar.R)
    >> 
    >> > maic <- min(aic)
    >> 
    >> > should be
    >> 
    >> > maic <- min(xaic)
    >> 
    >> > Note that, apparently, this typo/bug does little harm since the
    >> > subsequent line of code
    >> 
    >> > xaic <- setNames(if(is.finite(maic)) xaic - min(xaic) else
    >> > ifelse(xaic == maic, 0, Inf), 0L:order.max)
    >> 
    >> > does not use maic but min(xaic) directly. In any case, after fixing,
    >> > one could replace min(xaic) with maic to avoid recomputing min(xaic).
    >> > In absence of comments I will file a bug report.
    >> 
    >> I'm looking into this, thank you, Simone.
    >> This is not really a bug, e.g., in the sense of
    >> https://www.R-project.org/bugs.html ,
    >> as you mention yourself that the code works (flawlessly).
    >> 
    >> Still, of course,  (if you are right which I assume currently)
    >> it is a code infelicity we will be happy to fix.
    >> 
    >> Best,
    >> Martin
    >> 
    >> 
    >> > Kind regards
    >> > Simone
    >> 
    >> > Tested against R-devel 2026-03-06
    >> 
    >> > ___________________________________________________
    >> 
    >> > Simone Giannerini
    >> > Dipartimento di Scienze Economiche e Statistiche
    >> > Universita' di Udine
    >> > Via Tomadini 30/A - 33100 Udine,  ITALY
    >> > Tel: +39 0432 249577
    >> > https://simonegiannerini.net/
    >> 


    > -- 
    > ___________________________________________________

    > Simone Giannerini
    > Dipartimento di Scienze Economiche e Statistiche
    > Universita' di Udine
    > Via Tomadini 30/A - 33100 Udine,  ITALY
    > Tel: +39 0432 249577
    > https://simonegiannerini.net/
    > ___________________________________________________

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