How can I know which worker performs each iteration of the parfor loop?

I want to know if it is possible to determine which worker performs each iteration of the parfor loop or if it is possible to assign each iteration to a worker.

[Thomas Ibbotson]

We would usually advise against this, so it would be good to know why you want to do this. I will answer your question in detail below.

[Policarpo Abascal]

Thank you. I have found the answer to my question in the suggestions you provided with 'getcurrentworker'.

Answer 1

[Thomas Ibbotson]

You can find out which worker is running your code using the following function: https://uk.mathworks.com/help/parallel-computing/getcurrentworker.html

You can achieve more control over how iterations are divided amongst worker using parforOptions: https://uk.mathworks.com/help/parallel-computing/parforoptions.html

Answer 2

[Edric Ellis]

You can use getCurrentTask (if you're using a process pool rather than a thread pool). This has a field ID which tells you which task is operating, like this:

parfor i = 1:N
    t = getCurrentTask();
    fprintf('Iteration %d on task %d\n', i, t.ID);
end

It's not possible with parfor to assign iterations to workers. You can have more control with spmd - but we'd need to know more about what it is you're trying to achieve.

[Policarpo Abascal]

Thank you. This is the command I didn't know about and that solves what I wanted to address.