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

[Martin Maechler]

>>>>> Benjamin Tyner 
>>>>>     on Thu, 23 Jan 2020 08:16:03 -0500 writes:

    > On 1/20/20 12:33 PM, Martin Maechler wrote:
    >> 
    >> 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

    > For the record, I don't personally objects to the change here (as my 
    > philosophy tends toward treating most warnings as errors anyway) but for 
    > the sake of other useRs who may get bitten, perhaps we should be more 
    > explicit that backwards-compatibility won't be preserved under certain 
    > use patterns, for example:

    > # works (with warning) in R 3.6.2 but fails (with error) in R-devel:
    > vapply(list(1e9, 1e10),
    >        function(lambda) {
    >           rpois(1L, lambda)
    >        },
    >        FUN.VALUE = integer(1L)
    >        )

Well, some people are too picky...
use numeric(), not integer() in such cases :

> vapply(1:10, function(i) if(runif(1) < 0.5) 1L else 2, FUN.VALUE=pi)
 [1] 1 1 2 2 2 2 1 1 2 1
> 

No, really,  I don't plan to spend time "bloating" the
documentation any further,
when noticing that only a "few parts in a billion"  people carefully read
our help pages where the remaining  99.999% percent rather try
things in the R console and draw (often) wrong conclusions...

I *am* glad and grateful for careful and accurate R users and
bug-squashing helpers such as you or Suharto or ...

Martin

    > # in R-devel, a little extra work to achieve a warning as before:
    > vapply(list(1e9, 1e10),
    >        function(lambda) {
    >           tmp <- rpois(1L, lambda)
    >           if (!is.integer(tmp)) {
    >              warning("NAs produced")
    >              tmp <- NA_integer_
    >           }
    >           tmp
    >        },
    >        FUN.VALUE = integer(1L)
    >        )

    > (and yes I realize that rpois() vectorizes on lambda, so vapply is 
    > re-inventing the wheel in this toy example, but there could be (?) a 
    > justified use for it in more complicated simulations).