Re: octave going parallel

[Olaf Till]

On Thu, Apr 06, 2017 at 07:19:22PM +0200, christoph wrote:
> Hello,
> 
> Has anyone experience in doing parallel application with  octave? As I have
> 32 threads available in Linux it is poor seeing octave just using one core!
> I used parcellfun already and it seems to work fine, my question would be,
> what will happen if I use parcellfun in a function and call this function in
> a  pararrayfun.
> 
> ss=[array]
> 
> tt=pararray(32,@calculate,ss);
> 
> 
> *calculate* is a function like
> 
> 
> function[tt]=calculate(matrix,varargin)
> 
> do some code
> 
> do more code
> 
> then call
> 
> pattern = parcellfun (30, @findpattern,sliced_matrix);
> 
> do more code
> 
> even more code
> 
> endfunction
> 
> Is this going to work??
> 
> What is going to happen when a parfunction calls a parfunction ??

It should work. But your example may generate up to 960 computing
child processes, which the kernel has to schedule to your 32 cores. If
you still get a speedup depends on your code and your machine and has
to be tested.

Note that Octave may internally parallelize certain steps of
computation even without being told so.

Olaf

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