MATLAB: The Matlab 2017a has a restriction on the number of “workers”

bugMATLABParallel Computing Toolboxparallel pool

In earlier versions of MATLAB there was a restriction on the number of 'workers' – there was a maximum of 12, but this was lifted as of 2015a. As I am using 2017a, I should not be experiencing this. I have checked my 'numcores', here is the result.

>> feature('numcores')

MATLAB detected: 16 physical cores.

MATLAB detected: 16 logical cores.

MATLAB was assigned: 16 logical cores by the OS.

MATLAB is using: 16 logical cores.

but when I run my program, Matlab shows

Starting parallel pool (parpool) using the 'local' profile …

connected to 12 workers.

Best Answer

Open up the parallel preferences. What is the preferred number of workers in a parallel pool listed in the preferences?

Also open the Cluster Profile Manager using the link on the preferences window and check the NumWorkers property to ensure it has not been set explicitly to open 12 workers.

Related Solutions

MATLAB: What is the maximum numbers of workers I can use with MATLAB Parallel Computing Toolbox

All releases newer than R2013b do not have a limit on the number of workers (CPU cores) a local machine can utilize through Parallel Computing Toolbox. Prior to R2014a, the maximum number of workers was 12.

Please note that the default number of workers Parallel Computing Toolbox will attempt to use is 12. This number can be set higher in the "local" cluster profile. Additionally, if you edit the profile and leave the number of workers as unset, Parallel Computing Toolbox will attempt to use a number of workers equal to the physical cores of the computer.

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

MATLAB: How to get the number of logical cores – parallel computing toolbox

Hi Miles,

One way would be to use 'evalc', which is like 'eval' but can redirect command window output. You need to double up on single quotes inside the outer quotes, so

core_info = evalc('feature(''numcores'')');

will give you a string variable containing " MATLAB detected .... etc. etc. " which you could then parse to get the number you want.

Best Answer

Related Solutions

MATLAB: What is the maximum numbers of workers I can use with MATLAB Parallel Computing Toolbox

MATLAB: How to get the number of logical cores – parallel computing toolbox

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