>>>>> 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
> 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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