comp.lang.idl-pvwave archive: archive » Re: IDL Matrix Multiply and Dual-Core CPUs

Home » Public Forums » archive » Re: IDL Matrix Multiply and Dual-Core CPUs

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: IDL Matrix Multiply and Dual-Core CPUs [message #60249]

Fri, 09 May 2008 11:34

Pierre V.
Messages: 13
Registered: December 2006

Junior Member

Hi Samuel,

I saw a very similar problem with my quad-core PC running XP (32 bit)
with 4gigs of ram. I re-ran my test script on our two-core, 4-gig
linux box and got similar results with just slightly different array
sizes. Here is the script I ran:

cpu, /reset

help, !cpu, /str

Nk = 258
K = fltarr(Nk, Nk)

;
; Case 1.
;
Npix = 129047
d = fltarr(Npix, Nk)
t0 = systime(1)

d #= K

t1 = systime(1) - t0

print, 'Case #1: ', Npix, t1

;
; Case 2.
;
Npix = Npix + 1
d = fltarr(Npix, Nk)
t0 = systime(1)

d #= K

t2 = systime(1) - t0

print, 'Case #2: ', Npix, t2

On each of our computers case #2 used all available cores while case
#1 only used one core. The only difference between them is the
dimension of one of the arrays (Npix) is simply incremented by one.
The total memory used by the IDL process during this test is never
more and two-hundred megs or so. There is no way this problem is due
to a lack of physical memory. The sizes of these arrays are also
significantly larger then the default minimum number of elements
(default = 10000) required to enable multi-threading.

Any ideas?
Pierre

Report message to a moderator

[Message index]

		Re: IDL Matrix Multiply and Dual-Core CPUs By: Pierre V. on Fri, 09 May 2008 11:34
		Re: IDL Matrix Multiply and Dual-Core CPUs By: s.haenger on Fri, 09 May 2008 11:28
		Re: IDL Matrix Multiply and Dual-Core CPUs By: Foldy Lajos on Fri, 09 May 2008 11:20
		Re: IDL Matrix Multiply and Dual-Core CPUs By: Foldy Lajos on Fri, 09 May 2008 11:16
		Re: IDL Matrix Multiply and Dual-Core CPUs By: Bringfried Stecklum on Fri, 09 May 2008 09:09
		Re: IDL Matrix Multiply and Dual-Core CPUs By: s.haenger on Tue, 20 May 2008 00:21
		Re: IDL Matrix Multiply and Dual-Core CPUs By: Karl[1] on Tue, 20 May 2008 11:19
		Re: IDL Matrix Multiply and Dual-Core CPUs By: s.haenger on Thu, 17 July 2008 01:42

Previous Topic:	Re: appending to column
Next Topic:	a question about IDLgrSurface

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 19:09:36 PDT 2025

Total time taken to generate the page: 0.01018 seconds