Using R in parallel on a 2 processor machine
Try reading the rw-FAQ! There is no way user processes in Windows XP can access all 4Gb of the address space, but if you tune both R and XP correctly you should be able to get above 2Gb in total. See the rw-FAQ for how to tune R. Nevertheless, as you have already been told, it is a lot easier to do this under a
On Mon, 15 Nov 2004, Graham Law wrote:
Hi, I have installed R (2.0.0) onto a two processor machine running Windows XP (these two processors have been split into 4 logical processors), with 4Gb of RAM. Rather than multi-threading, I wanted to run 2 instances of R on the machine in parallel, which uses two of the logical processors. Unfortunately, R seems to be accessing a total of 1Gb of RAM, not taking advantage of 2 lots of 1Gb. This has led to memory problems, with one R process using the RAM, and the other one running into memory problems.
Looking at previous posts on this issue, I have tried using gc(), to take back unused memory. This has allowed the two parallel processes to work, but has not given me access to the other 3Gb. Any help would be much appreciated into how R may run in parallel using more than 1Gb.
Brian D. Ripley, ripley at stats.ox.ac.uk 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