Date: Apr 8, 2013 3:28 AM
Author: kinor
Subject: Re: performance of parfor

"Steven_Lord" <slord@mathworks.com> wrote in message <kjn2k9$1p7$1@newscl01ah.mathworks.com>...
>
>
> "kinor " <kinor.removethiswithdot@gmx.de> wrote in message
> news:kjmo9e$pl6$1@newscl01ah.mathworks.com...

> > Edric M Ellis <eellis@mathworks.com> wrote in message
> > <ytw6201w39j.fsf@uk-eellis0l.dhcp.mathworks.com>...

> >> "kinor " <kinor.removethiswithdot@gmx.de> writes:
>
> *snip*
>

> > I looked in the help of rank, its multithreading is not mentioned there,
> > where did you know that?

>
> Technically the RANK function itself is not multithreaded, as it is a MATLAB
> function file and it doesn't use any of the parallel constructs like PARFOR
> or SPMD from Parallel Computing Toolbox.
>
> However, most of the time required to compute RANK is used by computation of
> the singular values of the input matrix using SVD, and SVD _is_
> multithreaded (under certain conditions, notably when the data is large
> enough.)
>
> http://www.mathworks.com/support/solutions/en/data/1-4PG4AN/index.html?solution=1-4PG4AN
>
> I'd say that's close enough to count Edric's statement as correct.
>
> --
> Steve Lord
> slord@mathworks.com
> To contact Technical Support use the Contact Us link on
> http://www.mathworks.com



Hi Steve

thanks a lot for the enlighting comment, I did not doubt Erics comment. I was just surprised.
thanks again Eric.

best regards
kinor

@ all

any idea why the last example i posted is not faster with parfor?