failed to open matlabpool

I'm trying to use the following command:

matlabpool('open', 8);

But it gives me an error:

You requested a minimum of 8 workers, but the cluster "local" has the NumWorkers property set to allow a maximum of 4 workers. The default value of NumWorkers for a Local cluster is the number of cores on the local machine.

According to the description, my desktop only has 4 cores. But actually, it has 8 processors. I use two different ways to verify it. 'feature' is a undocumented and unsupported matlab command.

feature('numcores')

returns 4 in my desktop with ubuntu system.

But when using command 'nproc' to get the number of processors, it gives me 8. Why does 'feature'return 4 while 'nproc' give 8?

Answer 1

[Walter Roberson]

nproc might include hyperthreading. MATLAB will not use hyperthreads unless you configure it to. (I do not recall what the step to do so is.)