MATLAB: Matlabpool Maximum Number of Local Workers on one computer – Parallel Computing

Question

Couple of questions… 1) Can someone from Mathworks clarify exactly how many local workers one can enable on one single machine? I've read 8 or 12 workers, but not sure which is correct since I've seen users complaining about not being able to access 4 of their 12 cores, but I've also seen 12 as the answer (see http://www.mathworks.com/help/toolbox/distcomp/matlabpool.html)

2) If one were to have, say, a single machine with 16 cores on it with a Matlab Distributed Computing license, can I simply say… 'matlabpool open 16' to activate all 16 local cores?

I'm in the market for a new machine and need to know the answers to decide which machine to get.

Thanks in advance.

Answer 1

The number of local workers available with Parallel Computing Toolbox and no MDCS has changed. When introduced, the limit was 4; this changed to 8 in R2009a; and to 12 in R2011b.

If you want to use 16 workers, you will need a 16-node MDCS licence, and you'll also need to set up some sort of scheduler to manage those. There are detailed instructions about how to do this here. Once you've done that, yes, you'll be able to do "matlabpool open 16".