Hi @Giuseppe Gallo, I'm assuming the corresponding message in the command window is that the parallel pool is starting up with X workers, correct? That's a bit different than how to tell if the loop is running parallel.
Graphically, you can tell if a pool is running by looking at the lower lefthand icon
Another way is to log onto the machine running the workers and look at the processes -- are there a collection of MATLABs running? If you're running the App locally, it's easy enough to bring up either the Windows Task Manager or Linux top utility.
Regarding if the loop is running in parallel, one option is to create a DataQueue to send updates back to the App on how far along the parfor loop has finished (the waitbar example they give is a poor mans' way) -- you could update plots, write to a file, etc.
An external function can start a pool (and in some cases will). Keep in mind, you can only have one parallel pool running at a time.
