How to parallel 4 works with PARFOR with a Core i3 in Matlab

Question

I have Matlab R2012b for Ubuntu 64 bits. I have a Intel Core i3 CPU M 330 @ 2.13GHz × 4.

I want to use parfor to parallelize 4 loops at same time. Becau

Answer 1

To programmatically change the value of NumWorkers from 2 to 4 of the local cluster profile, you can use:

myCluster = parcluster('local');
myCluster.NumWorkers = 4;  % 'Modified' property now TRUE
saveProfile(myCluster);    % 'local' profile now updated,
                           % 'Modified' property now FALSE    

Answer 2

To increase the default NumWorkers, open the Cluster Profile Manager (Parallel->Manage Cluster Profiles). Pick the localprofile, click edit, and increase NumWorkers to the maximum possible value (in your case 4). Now it is possible to create a matlabpool with more workers than physical cores on your machine.

However, note that using more workers than cores might lead to decreased performance as compared to having the same number of workers as cores.