Strange R behavior for product of two sum of integers
On Oct 20, 2011, at 1:45 AM, Lei Jiang wrote:
When using power operator ^, both the base and index are coerced to type "real". The range of "real" is larger than "integer". However, an ordinary multiplication operator * offers it to two integers (as always). So, to avoid the warning, just add "as.real(...)" to one or both multipliers (once one multiplier is "real", the other must be coerced to "real" in the operation):
sum(1000:1205)*as.real(sum(1000:1205))
[1] 51581223225
That does seem to be an infelicity that ought to be fixed. Using the infix addition operator does that same sort of coercions, so why would one expect the infix multiplication operator to refuse to do it? > (sum(1000:1205))*(sum(1000:1204) +1205) [1] 51581223225 > (sum(1000:1205))*(sum(1000:1204) +0) [1] 51307549650
David. > > HTH, > Lei > > > On Wed, Oct 19, 2011 at 7:44 PM, Lafaye de Micheaux Pierre < > lafaye at dms.umontreal.ca> wrote: > >> Dear gentlemen, >> >> Can you explain me why the following happens (any OS I think, and >> even on >> 64 bits)? >> >>> sum(1000:1205)^2 >> [1] 51581223225 >>> sum(1000:1205)*sum(1000:1205) >> [1] NA >> Warning message: >> In sum(1000:1205) * sum(1000:1205) : NAs produced by integer overflow >> >> Best, >> >> Pierre >> >> -- >> Pierre Lafaye de Micheaux >> Adresse courrier: >> D?partement de Math?matiques et Statistique >> Universit? de Montr?al >> CP 6128, succ. Centre-ville >> Montr?al, Qu?bec H3C 3J7 >> CANADA >> >> Adresse physique: >> D?partement de Math?matiques et Statistique >> Bureau 4249, Pavillon Andr?-Aisenstadt >> 2920, chemin de la Tour >> Montr?al, Qu?bec H3T 1J4 >> CANADA >> >> T?l.: (00-1) 514-343-6607 / Fax: (00-1) 514-343-5700 >> lafaye at dms.umontreal.ca >> http://www.biostatisticien.eu >> >> ______________________________**________________ >> R-help at r-project.org mailing list >> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help >> > >> PLEASE do read the posting guide http://www.R-project.org/** >> posting-guide.html <http://www.R-project.org/posting-guide.html> >> and provide commented, minimal, self-contained, reproducible code. >> > > > > -- > Lei Jiang > > Center for Computation and Technology/ > Department of Computer Science > Louisiana State University > > E-mail: ljiang at cct.lsu.edu > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. David Winsemius, MD West Hartford, CT