[R] Programmaticly finding number of processors by R code
Dear List Sorry if this question seems very basic. Is there a function to pro grammatically find number of processors in my system _ I want to pass this as a parameter to snow in some serial code to parallel code functions Regards Ajay Websites- http://decisionstats.com http://dudeofdata.com Linkedin- www.linkedin.com/in/ajayohri __ 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.
Re: [R] Programmaticly finding number of processors by R code
Without knowing your OS, there is no way anyone can tell you. And you probably want to know 'cores' rather than CPUs. And for some specific OSes, you will find answers in the archives. Beware that this is not a well-defined question: are these physical or virtual cores?, and having them in the system and being allowed to use them are different questions. Package 'multicore' is one that attempts to do this in its function detectCores (see the source code). And on Sparc Solaris it is pretty useless as it gives virtual CPUs, 8x the number of real CPUs. On Sun, 3 Oct 2010, Ajay Ohri wrote: Dear List Sorry if this question seems very basic. Is there a function to pro grammatically find number of processors in my system _ I want to pass this as a parameter to snow in some serial code to parallel code functions Regards Ajay Websites- http://decisionstats.com http://dudeofdata.com Linkedin- www.linkedin.com/in/ajayohri __ 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. -- Brian D. Ripley, rip...@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, UKFax: +44 1865 272595 __ 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.
Re: [R] Programmaticly finding number of processors by R code
windows and ubuntu linux are my OS intent is to use them in the snow makecluster statement so I am not sure what I need cores,cpus,real,virtual basically the max amount of clusters i can create on my machine 2) if I have a workgroup on windows - can i detect cores/cpus on the network using the detectcore Ajay Websites- http://decisionstats.com http://dudeofdata.com Linkedin- www.linkedin.com/in/ajayohri On Mon, Oct 4, 2010 at 1:25 AM, Prof Brian Ripley rip...@stats.ox.ac.ukwrote: Without knowing your OS, there is no way anyone can tell you. And you probably want to know 'cores' rather than CPUs. And for some specific OSes, you will find answers in the archives. Beware that this is not a well-defined question: are these physical or virtual cores?, and having them in the system and being allowed to use them are different questions. Package 'multicore' is one that attempts to do this in its function detectCores (see the source code). And on Sparc Solaris it is pretty useless as it gives virtual CPUs, 8x the number of real CPUs. On Sun, 3 Oct 2010, Ajay Ohri wrote: Dear List Sorry if this question seems very basic. Is there a function to pro grammatically find number of processors in my system _ I want to pass this as a parameter to snow in some serial code to parallel code functions Regards Ajay Websites- http://decisionstats.com http://dudeofdata.com Linkedin- www.linkedin.com/in/ajayohri __ 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. -- Brian D. Ripley, rip...@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, UKFax: +44 1865 272595 [[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.
Re: [R] Programmaticly finding number of processors by R code
If no-one replies with a better way, here's a way: under
POSIX-compliant systems, you can write a small C function and wrap it
in an R function.
The C program would be something like
#include unistd.h
void nProcessors(int n)
{
#ifdef _SC_NPROCESSORS_ONLN
long nProcessorsOnline = sysconf(_SC_NPROCESSORS_ONLN);
#else
long nProcessorsOnline = 2; // This is my guess - most computers
today have at least 2 cores
#endif
n = (int) nProcessorsOnline;
}
You need to compile the function into a dynamic library (shared
object on linux) and load the dynamic library with dyn.load before
using it.
The R wrapper would be a function along the lines of
nProcessors = function()
{
n = 0;
res = .C(nProcessors, n = as.integer(n));
res$n
}
I haven't actually tested the R function so please take this with a
grain of salt, but I do use the C function in my own C code. You may
also want to read this thread about potential pitfalls and
limitations, plus another (simpler) way that would work on linux:
http://forum.soft32.com/linux2/CPUs-machine-ftopict13343.html
AFAIK, this will not work on Windows because Windows is not POSIX
compliant, but I'm not sure.
Peter
On Sun, Oct 3, 2010 at 10:03 AM, Ajay Ohri ohri2...@gmail.com wrote:
Dear List
Sorry if this question seems very basic.
Is there a function to pro grammatically find number of processors in
my system _ I want to pass this as a parameter to snow in some serial
code to parallel code functions
Regards
Ajay
__
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.
Re: [R] Programmaticly finding number of processors by R code
In windows try this:
Sys.getenv('NUMBER_OF_PROCESSORS')
On Sun, Oct 3, 2010 at 2:03 PM, Ajay Ohri ohri2...@gmail.com wrote:
Dear List
Sorry if this question seems very basic.
Is there a function to pro grammatically find number of processors in
my system _ I want to pass this as a parameter to snow in some serial
code to parallel code functions
Regards
Ajay
Websites-
http://decisionstats.com
http://dudeofdata.com
Linkedin- www.linkedin.com/in/ajayohri
__
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.
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40 S 49° 16' 22 O
[[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.
Re: [R] Programmaticly finding number of processors by R code
If you have installed multicore (for unix/mac), you can find the number of cores by /*multicore:::detectCores()*/ On 10/3/10 1:03 PM, Ajay Ohri wrote: Dear List Sorry if this question seems very basic. Is there a function to pro grammatically find number of processors in my system _ I want to pass this as a parameter to snow in some serial code to parallel code functions Regards Ajay Websites- http://decisionstats.com http://dudeofdata.com Linkedin- www.linkedin.com/in/ajayohri __ 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. -- Abhijit Dasgupta, PhD Director and Principal Statistician ARAASTAT Ph: 301.385.3067 E: adasgu...@araastat.com W: http://www.araastat.com [[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.
