Parfor loop with 4 workers is more than 4 times faster than the for loop, how is it possible?

Hello,

I have a code that contains a for loop inside a while loop.

When I change the for to parfor, the elapsed time I get is divided by "n" times, being "n" higher than 4 for some input data.

How is it possible if my pool has 4 workers? I'm using tic/toc functions to measure the time.

Thank you!

Answer 1

[Edric Ellis]

Without seeing some code that demonstrates this, we can only speculate. One possibility is that the code transformations required to make a parfor loop execute have ended up being more efficient. Is your parfor loop currently in a script? (There are different MATLAB-level optimisations available to scripts and functions - but the body of a parfor loop always has to execute in the same was as if it was placed inside a function).