[slashvar2701]

That's a somewhat misleading wording for a classic rule of parallel algorithm: a thread is the owner of its computations.

So, each actor own a group of cells and is the only one able to modify them. This highly simplifies most algorithms, removes a lot of synchronization issues ...

This is also why in parallel algorithm you should split the outputs rather than the inputs.

[cogman10]

Often, I find that "if you are synchronizing, you are wrong". Doesn't mean you can't or shouldn't use synchronizing in cases where message passing is impractical. However, it does mean that it should be a last choice rather than a first choice. It is simply far too easy to get locks wrong.