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RE:Dual Core

  • To: mathgroup at smc.vnet.net
  • Subject: [mg70126] RE:Dual Core
  • From: markc.westwood at gmail.com
  • Date: Wed, 4 Oct 2006 06:00:08 -0400 (EDT)

Hi

Welcome to the world of performance evaluation.  You ask 'Is Mathematica really unable to use both cores at the same time ?' while the answer to the question is staring you in the face -- no it cannot.  You probably have a right to expect the operating system (if it is multicore aware) to distribute separate threads of execution onto different cores, so you can (again probably -- the only true answer is derived by testing and experimentation) run Excel on one core (in one thread) and Mathematica on the other (in another thread).

In general the task of splitting a computation onto 2 cores is the same as writing 2 programs which, cooperatively and while running at the same time, solve a problem.  Imagine, if you wish, writing 2 Mathematica programs to carry out 1 computation.  Not so easy.  And possibly we shouldn't expect Mathematica to do this automatically for us, not with the current state of the art.  I'm extremely doubtful that the internal workings of Solve, Reduce, etc are easily distributable onto multiple cores -- I guess someone from WRI will put me (us) right on that if I'm dead flat wrong.  Mathematica doesn't have, as languages such as Java do, programming constructs for managing separate threads of execution, unless you jump to MathLink programming.

If you watch the task manager very closely while you're working with Mathematica you might (just) see the front-end and the kernel on different cores since they are (and have long been) handled by different threads of execution.  But the amount of time most of us spend in the front-end is insignificant and it may not appear high up the list of tasks if at all.

Reference to the WRI site does show that there is a 64-bit multicore version of Mathematica available.  I would be interested (and other readers of this thread too I guess) in knowing if you are using this version -- in which case you probably feel very disappointed.  I'd also be interested in learning from users of that version whether Mathematica can indeed distribute a single command such as Solve or Reduce over multiple cores.  That's something I might even pay money for.

Hope this helps

Regards
Mark

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