[R] Information on the number of CPU's

tolga.i.uzuner at jpmorgan.com tolga.i.uzuner at jpmorgan.com
Tue Sep 9 22:01:23 CEST 2008

Many thanks, that's very helpful.

----- Original Message -----
From: Prof Brian Ripley [ripley at stats.ox.ac.uk]
Sent: 09/09/2008 20:57 CET
To: Tolga Uzuner
Cc: r-help at r-project.org
Subject: Re: [R] Information on the number of CPU's

On Tue, 9 Sep 2008, tolga.i.uzuner at jpmorgan.com wrote:

> Dear R Users,
> I am on Windows XP SP2 platform, using R version 2.7.2 . I was wondering
> if there is a way to find out, within R, the number of CPU's on my machine
> ? I would use this information to set the number of nodes in a cluster,
> depending on the machine. Sys.info() and .Platform do not carry this
> information.

Correct, since

a) R does not make use of more than 1.

b) It is really not portable, and not even well-defined.  (How many CPUs 
has a hyperthreaded dual Xeon?  Some say 2, some say 4.  Do you want 
CPUs or cores?  If this is a virtualized OS, is the physical number or the 
logical number?)

In the case of Windows, how depends on the Windows version.  The w32api 
(XP or later) call GetNativeSystemInfo will tell you the number of CPUs, 
for some (unstated) definition of 'CPU'.  Later versions have 
GetLogicalProcessorInformation, which can give the number of cores.

> Thanks in advance,
> Tolga Uzuner

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
Generally, this communication is for informational purposes only
and it is not intended as an offer or solicitation for the purchase
or sale of any financial instrument or as an official confirmation
of any transaction. In the event you are receiving the offering
materials attached below related to your interest in hedge funds or
private equity, this communication may be intended as an offer or
solicitation for the purchase or sale of such fund(s).  All market
prices, data and other information are not warranted as to
completeness or accuracy and are subject to change without notice.
Any comments or statements made herein do not necessarily reflect
those of JPMorgan Chase & Co., its subsidiaries and affiliates.

This transmission may contain information that is privileged,
confidential, legally privileged, and/or exempt from disclosure
under applicable law. If you are not the intended recipient, you
are hereby notified that any disclosure, copying, distribution, or
use of the information contained herein (including any reliance
thereon) is STRICTLY PROHIBITED. Although this transmission and any
attachments are believed to be free of any virus or other defect
that might affect any computer system into which it is received and
opened, it is the responsibility of the recipient to ensure that it
is virus free and no responsibility is accepted by JPMorgan Chase &
Co., its subsidiaries and affiliates, as applicable, for any loss
or damage arising in any way from its use. If you received this
transmission in error, please immediately contact the sender and
destroy the material in its entirety, whether in electronic or hard
copy format. Thank you.
Please refer to http://www.jpmorgan.com/pages/disclosures for
disclosures relating to UK legal entities.

More information about the R-help mailing list