[R] outer(-x, x, pmin) cannot allocate
Roger D. Peng
rpeng at jhsph.edu
Wed Dec 22 23:48:19 CET 2004
Actually, I believe it's 8 bytes for double precision.
Berton Gunter wrote:
> In general, this is not a good question to ask, as one needs to go into the
> bowels of R to find an answer.
> But note that 8000 x 8000 x 4 bytes for double precision = 256 mb. Now look
> at the code of outer(). Two vectors of this size are created = 512mb. Then
> copies of these must be created to be passed into pmin, I believe, as R
> passes by value. That's 1gb.
> My guess is that "+", as an internal function, avoids the final doubling.
> Corrections/clarifications by knowledgeable R experts cheerfully welcomed.
> I'm on thin ice here.
> -- Bert Gunter
> Genentech Non-Clinical Statistics
> South San Francisco, CA
> "The business of the statistician is to catalyze the scientific learning
> process." - George E. P. Box
>>From: r-help-bounces at stat.math.ethz.ch
>>[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Brahm, David
>>Sent: Wednesday, December 22, 2004 12:11 PM
>>To: r-help at stat.math.ethz.ch
>>Subject: [R] outer(-x, x, pmin) cannot allocate
>>R> x <- 0. + 1:8000
>>R> y <- outer(-x, x, pmin)
>>Error: cannot allocate vector of size 1000000 Kb
>>Why does R need to allocate a gigabyte to create an 8000 x
>>It doesn't have any trouble with outer(-x, x, "+"). Thanks.
>>-- David Brahm (brahm at alum.mit.edu)
>> platform = i686-pc-linux-gnu
>> arch = i686
>> os = linux-gnu
>> system = i686, linux-gnu
>> status =
>> major = 2
>> minor = 0.1
>> year = 2004
>> month = 11
>> day = 15
>> language = R
>>R-help at stat.math.ethz.ch mailing list
>>PLEASE do read the posting guide!
> R-help at stat.math.ethz.ch mailing list
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Roger D. Peng
More information about the R-help