Thank you, Henrik! That makes more sense now. You mentioned that every double value needs 8 bytes. So, in R, how many decimal point, or any number smaller than, say 10^4 are considered as double value ? (Sorry I don't have any C or Java language background, and couldn't find it for R. )
I appreciate your explanation and helps! On Tue, Oct 5, 2010 at 8:32 PM, Henrik Bengtsson <h...@stat.berkeley.edu>wrote: > On Tue, Oct 5, 2010 at 5:21 PM, Carrie Li <carrieands...@gmail.com> wrote: > > I am sorry that it has been couple days. > > I've read the website you provided below, but still don't quite know if > this > > is doable. > > The maximum vector length is 2^31-1, so here is what I tired, and it > > returned errors as below. > > > > > > P=20000 > > D=matrix(rep(0, P*P), nrow=P) > > > > Error: cannot allocate vector of size 1.5 Gb > > In addition: Warning messages: > > 1: In as.vector(data) : > > Reached total allocation of 1535Mb: see help(memory.size) > > > > On the manuals, it says "32-bit OSes by default limit file sizes to 2GB > ", > > so why P=20000 is not working here ? > > Every double value (e.g. 0) needs 8 bytes. So the total memory needed > for that matrix is 8*P*P = 3.2e+09 bytes = 3.2e+09/1024^3 Gb = 2.98Gb. > Now, in order to do anything useful you also need space for creating > an internal copy or two of that object. That is, you basically need > 2-3 times more *free* (and *contiguous/non-fragmented*) RAM than that > to do anything useful. > > /Henrik > > > > > Thanks for any helps. I appreciate. > > > > > > On Sat, Oct 2, 2010 at 12:22 PM, Marc Schwartz <marc_schwa...@me.com> > wrote: > > > >> On Oct 2, 2010, at 11:14 AM, Carrie Li wrote: > >> > >> > Hi everyone, > >> > > >> > If I run on a 64-bit R, what is the maximum matrix size that it can > >> handle ? > >> > Is a matrix 20,000 x 20,000 possible on 32 bit ? > >> > Thanks for answering! > >> > >> > >> A matrix is a vector with 'dim' attributes. The maximum vector length is > >> 2^31 - 1 and that does not change between 32 and 64 bit R. The primary > >> advantage of 64 bit R is the larger memory address space. > >> > >> See: > >> > >> > >> > http://cran.r-project.org/doc/manuals/R-admin.html#Choosing-between-32_002d-and-64_002dbit-builds > >> > >> HTH, > >> > >> Marc Schwartz > >> > >> > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@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. > > > [[alternative HTML version deleted]] ______________________________________________ R-help@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.
