Thread Subject: Why remove maxNumCompThreads in future versions?

With the release of R2009b, the maxNumCompThreads command is announced to be removed in future releases:

---
Note maxNumCompThreads will be removed in a future version. You can set the -singleCompThread option when starting MATLAB to limit MATLAB to a single computational thread. By default, MATLAB makes use of the multithreading capabilities of the computer on which it is running.
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For what reason? I find the command very useful for various reasons:
1) test scalability of a program/command
2) limiting resources when sharing a computer with different users

Anyone else who likes to keep this command in future releases?

--
Sebastiaan

"Sebastiaan" <s.breedveld@erasmusmc.REMOVE.BOO.BOO.nl> wrote in message
news:h8qppm$lj4$1@fred.mathworks.com...
> With the release of R2009b, the maxNumCompThreads command is announced to
> be removed in future releases:
>
> ---
> Note maxNumCompThreads will be removed in a future version. You can set
> the -singleCompThread option when starting MATLAB to limit MATLAB to a
> single computational thread. By default, MATLAB makes use of the
> multithreading capabilities of the computer on which it is running.
> ---
>
> For what reason? I find the command very useful for various reasons:
> 1) test scalability of a program/command
> 2) limiting resources when sharing a computer with different users
>
> Anyone else who likes to keep this command in future releases?

maxNumCompThreads is being removed for (in part) the same reasons we removed
the capability to control the number of threads via the Preferences panel in
R2009a:

http://www.mathworks.com/access/helpdesk/help/techdoc/rn/bry1ecg-1.html#br1ask3-1

--
Steve Lord
slord@mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ

"Steven Lord" <slord@mathworks.com> wrote in message

> maxNumCompThreads is being removed for (in part) the same reasons we removed
> the capability to control the number of threads via the Preferences panel in
> R2009a:
>
> http://www.mathworks.com/access/helpdesk/help/techdoc/rn/bry1ecg-1.html#br1ask3-1
>
Does this mean that Matlab is going to have a more advanced execution scheme in future releases? E.g.

for i=1:10
 A{i} = rand(i,i);
 b{i} = ones(i, 1);
 x{i} = A{i}\b{i};
end

Will the loop be multithreaded into 10 threads (without the parallel computing toolbox), whereas the linsolve uses the OpenMP multithreading?

Hi,

is there any way of finding out how many threads are going to be used and controlling this number when starting new matlab session?

Our machines are shared among multiple users and the policy desn't allow one to use all cores. However, -singleCompThread is too limiting. maxNumCompThread was a nice feature but since it's not supported anymore, it's very difficult to run some of our experiments.

Thank you
Ondrej Glembek


"Steven Lord" <slord@mathworks.com> wrote in message <h9035k$9a8$1@fred.mathworks.com>...
>
> "Sebastiaan" <s.breedveld@erasmusmc.REMOVE.BOO.BOO.nl> wrote in message
> news:h8qppm$lj4$1@fred.mathworks.com...
> > With the release of R2009b, the maxNumCompThreads command is announced to
> > be removed in future releases:
> >
> > ---
> > Note maxNumCompThreads will be removed in a future version. You can set
> > the -singleCompThread option when starting MATLAB to limit MATLAB to a
> > single computational thread. By default, MATLAB makes use of the
> > multithreading capabilities of the computer on which it is running.
> > ---
> >
> > For what reason? I find the command very useful for various reasons:
> > 1) test scalability of a program/command
> > 2) limiting resources when sharing a computer with different users
> >
> > Anyone else who likes to keep this command in future releases?
>
> maxNumCompThreads is being removed for (in part) the same reasons we removed
> the capability to control the number of threads via the Preferences panel in
> R2009a:
>
> http://www.mathworks.com/access/helpdesk/help/techdoc/rn/bry1ecg-1.html#br1ask3-1
>
> --
> Steve Lord
> slord@mathworks.com
> comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ
>