On 2014/07/04, 22:59 , Roger Hui wrote:
I have observed a puzzling timing result which may be CPU dependent.
Please try the following and tell me what ratio you get, and the kind of
machine you ran it on. Thanks.
On my machine, an XPS L521X Intel Core i7-3632QM @ 2.2 GHz,
x=: 1e6 $ ' '
y=: a. {~ ? 1e6 $ 256
%/ 100 (6!:2)&> '/:~x' ; '/:~y'
2.44133
Basically, sorting a constant vector of 1-byte ints takes 2.4 times as long
as sorting a random vector of 1-byte ints.
NB. on iMac 2.93 GHz Intel Core i7
JVERSION
Engine: j701/2011-01-10/11:25 build: Feb 6 2011 16:16:29
Library: 8.01.020
Platform: Darwin 64
Installer: j801 install
InstallPath: /Applications/j64-801
x=: 1e6 $ ' '
y=: a. {~ ? 1e6 $ 256
%/ 100 (6!:2)&> '/:~x' ; '/:~y'
1.12132
jkt@set1:~$ ijconsole
x=: 1e6 $ ' '
y=: a. {~ ? 1e6 $ 256
%/ 100 (6!:2)&> '/:~x' ; '/:~y'
0.999385
JVERSION
Engine: j701/2011-01-10/11:25
Library: 8.02.10
Platform: Linux 64
Installer: unknown
InstallPath: /usr/share/j/8.0.2
host 'cat /proc/cpuinfo'
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 30
model name : Intel(R) Xeon(R) CPU X3430 @ 2.40GHz
stepping : 5
microcode : 0x3
cpu MHz : 1200.000
cache size : 8192 KB
NB. On iPhone 5S
x=: 1e6 $ ' '
y=: a. {~ ? 1e6 $ 256
%/ 100 (6!:2)&> '/:~x' ; '/:~y'
1.92691
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