[Rd] [External] Re: rpois(9, 1e10)

[Spencer Graves]

On 2020-01-22 02:54, Martin Maechler wrote:
>>>>>> Martin Maechler
>>>>>>      on Tue, 21 Jan 2020 09:25:19 +0100 writes:
>>>>>> Ben Bolker
>>>>>>      on Mon, 20 Jan 2020 12:54:52 -0500 writes:
>      >> Ugh, sounds like competing priorities.
>
>      > indeed.
>
>      >> * maintain type consistency
>      >> * minimize storage (= current version, since 3.0.0)
>      >> * maximize utility for large lambda (= proposed change)
>      >> * keep user interface, and code, simple (e.g., it would be easy enough
>      >> to add a switch that provided user control of int vs double return value)
>      >> * backward compatibility
>
>      > Last night, it came to my mind that we should do what we have
>      > been doing in quite a few places in R, the last couple of years:
>
>      > Return integer when possible, and switch to return double when
>      > integers don't fit.
>
>      > We've been doing so even for  1:N  (well, now with additional ALTREP wrapper),
>      > seq(), and even the fundamental  length()  function.
>
>      > So I sat down and implemented it .. and it seemed to work
>      > perfectly:  Returning the same random numbers as now, but
>      > switching to use double (instead of returning NAs) when the
>      > values are too large.
>
>      > I'll probably commit that to R-devel quite soonish.
>      > Martin
>
> Committed in svn rev 77690; this is really very advantageous, as
> in some cases / applications or even just limit cases, you'd
> easily get into overflow sitations.
>
> The new R 4.0.0 behavior is IMO  "the best of" being memory
> efficient (integer storage) in most cases (back compatible to R 3.x.x) and
> returning desired random numbers in large cases (compatible to R <= 2.x.x).
>
> Martin


Wunderbar!  Sehr gut gemacht!  ("Wonderful!  Very well done!") Thanks, 
Spencer
>
>      >> On 2020-01-20 12:33 p.m., Martin Maechler wrote:
>      >>>>>>>> Benjamin Tyner
>      >>>>>>>> on Mon, 20 Jan 2020 08:10:49 -0500 writes:
>      >>>
>      >>> > On 1/20/20 4:26 AM, Martin Maechler wrote:
>      >>> >> Coming late here -- after enjoying a proper weekend ;-) --
>      >>> >> I have been agreeing (with Spencer, IIUC) on this for a long
>      >>> >> time (~ 3 yrs, or more?), namely that I've come to see it as a
>      >>> >> "design bug" that  rpois() {and similar} must return return typeof() "integer".
>      >>> >>
>      >>> >> More strongly, I'm actually pretty convinced they should return
>      >>> >> (integer-valued) double instead of NA_integer_   and for that
>      >>> >> reason should always return double:
>      >>> >> Even if we have (hopefully) a native 64bit integer in R,
>      >>> >> 2^64 is still teeny tiny compared .Machine$double.max
>      >>> >>
>      >>> >> (and then maybe we'd have .Machine$longdouble.max  which would
>      >>> >> be considerably larger than double.max unless on Windows, where
>      >>> >> the wise men at Microsoft decided to keep their workload simple
>      >>> >> by defining "long double := double" - as 'long double'
>      >>> >> unfortunately is not well defined by C standards)
>      >>> >>
>      >>> >> Martin
>      >>> >>
>      >>> > Martin if you are in favor, then certainly no objection from me! ;-)
>      >>>
>      >>> > So now what about other discrete distributions e.g. could a similar
>      >>> > enhancement apply here?
>      >>>
>      >>>
>      >>> >> rgeom(10L, 1e-10)
>      >>> >  [1]         NA 1503061294         NA         NA 1122447583         NA
>      >>> >  [7]         NA         NA         NA         NA
>      >>> > Warning message:
>      >>> > In rgeom(10L, 1e-10) : NAs produced
>      >>>
>      >>> yes, of course there are several such distributions.
>      >>>
>      >>> It's really something that should be discussed (possibly not
>      >>> here, .. but then I've started it here ...).
>      >>>
>      >>> The  NEWS  for R 3.0.0 contain (in NEW FEATURES) :
>      >>>
>      >>> * Functions rbinom(), rgeom(), rhyper(), rpois(), rnbinom(),
>      >>> rsignrank() and rwilcox() now return integer (not double)
>      >>> vectors.  This halves the storage requirements for large
>      >>> simulations.
>      >>>
>      >>> and what I've been suggesting is to revert this change
>      >>> (svn rev r60225-6) which was purposefully and diligently done by
>      >>> a fellow R core member, so indeed must be debatable.
>      >>>
>      >>> Martin
>      >>>
>      >>> ______________________________________________
>      >>> R-devel using r-project.org mailing list
>      >>> https://stat.ethz.ch/mailman/listinfo/r-devel
>      >>>
>
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