Parfor iterations and number of cores

I am using parfor for the first time. I run a piece of code 'multiple' times and get an output y each time. Finally, I take average of all such y to get the avg_y. So, I decided to use parfor for the 'multiple' times.

My laptop is quad core and my question is that can't I run the parfor more than 4 times? As I want to run the parfor loop code 10 times and then average the y values....

Answer 1

[Matt J]

The number of loop iterations isn't limited by the number of cores you have. However, if you have 4 cores, the loop iterations cannot be split into more than 4 parallel groups. So, for example, if you have 40 loop iterations, each core must do 10 of them.

[Jaya]

That means, I need not do anything and directly do the parfor for 10 iterations and it will take care how to divide the tasks? Then, I (or code) can just average all the 10 outputs at the end normally?

[Matt J]

Yes.

[Jaya]

Thanks. I did that later. Actually I asked another question related to this but the reverse case. Can you please take a look at that also? Link is https://www.mathworks.com/matlabcentral/answers/1581179-specifying-more-cores-than-needed-for-parfor-any-speedup