[R-SIG-Mac] detecting cores

Prof Brian Ripley ripley at stats.ox.ac.uk
Fri Feb 5 13:07:04 CET 2016

sysctl on 10.11 has options which would enable us to differentiate 
between logical and physical codes on parallel::detectCores --- however 
these are not documented in Apple's online man pages, which are for 
10.9.  Could someone running 10.9 and someone for 10.10 report if

/usr/sbin/sysctl -n hw.physicalcpu
/usr/sbin/sysctl -n hw.logicalcpu

run in a terminal work and gives the correct result?  (Normally the 
second will be twice the first taking account of hyperthreading.)

Thanks in advance.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Emeritus Professor of Applied Statistics, University of Oxford

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