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
>>>
>>> ______________________________________________
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>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>>
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