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MathGroup Archive 2006

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Re: Re: Re: why does not the Mathematica kernel seem to 'multi-task' between computations in different windows?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg69956] Re: [mg69892] Re: [mg69866] Re: why does not the Mathematica kernel seem to 'multi-task' between computations in different windows?
  • From: "Chris Chiasson" <chris at chiasson.name>
  • Date: Thu, 28 Sep 2006 06:15:30 -0400 (EDT)
  • References: <200609271003.GAA00051@smc.vnet.net>

How about just buying one license with premier support? Then you can
install Mathematica on a second computer and use it as a source of two
remote kernels, in addition to the local computer's two kernels.

On 9/27/06, Benedetto Bongiorno <bbongiorno at attglobal.net> wrote:
> Mathgroup,
>
> I have been talking to Wolfram on the same issue.
> I am in the process of purchasing a computer configuration that will
> allow us to run
> four notebooks simultaneously on a Windows XP 64 bit OS, using two
> Opteron dual cores.
> Wolfram has advised that one license of 5.2 will allow you to run two
> notebooks simultaneously,
> using one dual core processor. If we buy another license we can run two
> additional notebooks simultaneously,
> using second dual core processor.
> Wolfram has made it clear all variables for each notebook's kernel  is
> confined to a core of the dual processor.
> Wolfram's PersonalGrid appears to do the same thing with more functionality.
>
> Does anyone else have any experience in this area?
>
> Thank you,
> Ben
>
> ben wrote:
> > Hi,
> >
> > I suggest to check the manual about the difference between
> > mathematica frontent (windows) and mathematica kernel (computation
> > client):
> >
> > The frontend only displays your worksheet nicely, handles editing and
> > sends
> > commands to the kernel; its the kernel that does all the computation
> > work.
> >
> > Now the point is: You can open several frontends which
> > by default will all be linked to the same instance of the kernel.
> >
> > This has two surprising effects,
> >
> > 1. A kernel which is busy with a command from frontend no.1 is simply
> > busy, it can not do computations for frontend no.2 in the same time
> >
> > 2. All variables are stored by the kernel, that is a variable defined
> > in frontend no.1
> > is visible also in frontend no.2
> >
> > Effect 2 makes clear why you cannot have multi-tasking: results would
> > be not defined uniquely, since results from frontend no.2 can effect
> > the state of the variables and thus computations in frontend no.1 and
> > vice versa, and if you do not know which of two calculations running
> > parallel finishes first you might end up in a whole mess.
> >
> > What's now the solution to your problem?
> >
> > Kernel->Kernel Configure Options allows you to add additional kernels
> > (make them local for simplicity)
> > Then by
> > Kernel->Notebook's Kernel
> > you can assign a unique kernel to each notebook.
> > This will use up extra memory and maybe licences too.
> >
> > Hope that helps
> > Ben
> >
> > Nasser Abbasi schrieb:
> >
> >
> >> Hi
> >>
> >> Sometime I start some computation in one window which can take few minutes
> >> to half an hour or more.
> >>
> >> It seems anything I type meanwhile in a second window does not get processed
> >> until the first computation is completed.
> >>
> >> The computation does have 'Print[]' statements in it for debugging, so it is
> >> not completely CPU bound, and I would think that one should be able to do
> >> someone work in the second window meanwhile even if it might be slower to
> >> respond.
> >>
> >> It seems that the Mathematica kernel can't be preempted at all once it
> >> starts a computation, even if I/O calls are being made.
> >>
> >> Right now, once I start something, I can't use Mathematica at all until the
> >> computation is over because the kernel is busy. (Except it seems I am able
> >> to do File->Save ok while it is busy)
> >>
> >> Sometimes I start a second copy of Mathematica, but the limit is 2 instances
> >> and I do not have lots of RAM.  I also wonder if this limit should be
> >> increased to say 5.
> >>
> >> I guess it is time for me to go buy a PC with those Intel new chips the
> >> core2 with lots of RAM as I spend too much time now waiting for something to
> >> complete.
> >>
> >> Nasser
> >>
> >
> >
> >
> >
>
>


-- 
http://chris.chiasson.name/


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