Re: Enable multicore calculation ?
- To: mathgroup at smc.vnet.net
- Subject: [mg88164] Re: Enable multicore calculation ?
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Sun, 27 Apr 2008 04:56:38 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <fuumac$877$1@smc.vnet.net>
guerom00 wrote:
> I'm running Mathematica 6.0.2 on a MacPro with 8 cores. I've noticed
> that the kernel only uses 1 core=85 Is it possible to enable multicore
> calculations ?
By default, a regular version of Mathematica 6.0.2 for Mac OS X on Intel
Mac uses its *multi-threading* capabilities [1].
Which means that some functions (mostly linear algebra) may use
extensively more than one core at some point during a computation.
Which also means that only a small subset of Mathematica functions have
natively multi-threading capabilities and one cannot write one's own
parallel/multi-threaded functions with a regular version of Mathematica.
To do so, depending of your needs and budget, several solutions are
available from WRI [3, 4, 5].
So to see many cores used on oneâ??s multi-core system, one may try a
singular value decomposition or compute eigenvalues on a large numeric
matrix.
Your mileage may vary, but on my dual-core system, the SVD starts by
using mostly only one core, then, after a while both core are used (as
seen thanks to the Activity Monitor or the top command). On the other
hand, the eigenvalues used mostly one core at a time (i.e. starts on one
core, then switches to the other, then comes back to the first core).
Timing[
SingularValueDecomposition[RandomReal[1, {3000, 3000}]];]
(* {105.685, Null} *)
Timing[Eigenvalues[RandomReal[1, {2500, 2500}]];]
(* {109.357, Null} *)
$Version
(* "6.0 for Mac OS X x86 (64-bit) (February 7, 2008)" *)
HTH,
Jean-Marc
[1] http://forums.wolfram.com/mathgroup/archive/2006/Apr/msg00708.html
[2] "Does Mathematica take advantage of multiple processors?"
http://support.wolfram.com/mathematica/systems/allplatforms/multipleprocessors.en.html
[3] "Wolfram gridMathematica"
http://www.wolfram.com/products/gridmathematica/
[4] "Wolfram Mathematica Parallel Computing Toolkit"
http://www.wolfram.com/products/applications/parallel/
[5] "Wolfram Mathematica Personal Grid Edition"
http://www.wolfram.com/products/personalgrid/