A technical question here: how does one measure the memory overhead mentioned below? I have a set of functions of my own and would like to profile them.
Thanks, Vadim > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Prof > Brian Ripley > Sent: Sunday, December 26, 2004 2:04 AM > To: [EMAIL PROTECTED] > Subject: [Rd] R's IO speed > > R-devel now has some improved versions of read.table and write.table. > > For a million-row data frame containing one number, one > factor with few levels and one logical column, a 56Mb object. > > generating it takes 4.5 secs. > > calling summary() on it takes 2.2 secs. > > writing it takes 8 secs and an additional 10Mb. > > saving it in .rda format takes 4 secs. > > reading it naively takes 28 secs and an additional 240Mb > > reading it carefully (using nrows, colClasses and > comment.char) takes 16 secs and an additional 150Mb (56Mb of > which is for the object read in). > (The overhead of read.table over scan was about 2 secs, > mainly in the conversion back to a factor.) > > loading from .rda format takes 3.4 secs. > > [R 2.0.1 read in 23 secs using an additional 210Mb, and wrote > in 50 secs using an additional 450Mb.] > > > Will Frank Harrell or someone else please explain to me a > real application > in which this is not fast enough? > > -- > Brian D. Ripley, [EMAIL PROTECTED] > Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ > University of Oxford, Tel: +44 1865 272861 (self) > 1 South Parks Road, +44 1865 272866 (PA) > Oxford OX1 3TG, UK Fax: +44 1865 272595 > > ______________________________________________ > R-devel@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > ______________________________________________ R-devel@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-devel