What is the maximum number of workers I can use with the 'Processes' or 'local' profile in the Parallel Computing Toolbox?

I have installed Parallel Computing Toolbox and wish to make use of all the processor cores on my computer. What is the maximum number of workers I can use with Parallel Computing Toolbox?

Answer 1

[MathWorks Support Team]

All releases from R2014a onwards can utilize up to 512 workers on a local machine through Parallel Computing Toolbox. For R2013b and earlier, the maximum number of workers was 12.

By default Parallel Computing Toolbox will attempt to use a number of workers equal to the number physical cores of the computer. 

Prior to R2023a if parpool('local') is called without a specific number of workers the Parallel Preferences will set a preferred number of workers in the pool. The default value for this is 12 workers or the number of workers set in the cluster profile (whichever is lower).

If you wish to use multiple computers to perform parallel and distributed job processing, MATLAB Parallel Server will be required to utilize computational resources of other machines.

See also: 

http://www.mathworks.com/matlabcentral/answers/2042101-how-can-i-increase-the-number-of-matlab-workers-inside-parallel-computing-toolbox-to-use-all-the-log

for information on why the number of cores detected might not be all of the cores on your machine.