R help - Oct 2011 - Strange R behavior for product of two sum of integers

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

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

HTH,
Lei


On Wed, Oct 19, 2011 at 7:44 PM, Lafaye de Micheaux Pierre <
lafaye@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:
> Département de Mathématiques et Statistique
> Université de Montréal
> CP 6128, succ. Centre-ville
> Montréal, Québec H3C 3J7
> CANADA
>
> Adresse physique:
> Département de Mathématiques et Statistique
> Bureau 4249, Pavillon André-Aisenstadt
> 2920, chemin de la Tour
> Montréal, Québec H3T 1J4
> CANADA
>
> Tél.: (00-1) 514-343-6607 / Fax: (00-1) 514-343-5700
> lafaye@dms.umontreal.ca
> http://www.biostatisticien.eu
>
> ______________________________**________________
> R-help@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@cct.lsu.edu

	[[alternative HTML version deleted]]

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

On Thu, Oct 20, 2011 at 7:50 AM, David Winsemius <dwinsemius at
comcast.net> wrote:
>
> 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?
This turns out not to be the case:
> x<-2147483647L
> y<-2147483647L
> x+y
[1] NA
Warning message:
In x + y : NAs produced by integer overflow

    -thomas

-- 
Thomas Lumley
Professor of Biostatistics
University of Auckland