Local variables and clusters

[PRoman]

I not absolutely understand how work the appeal to clusters through local variables. Really if in one place I write one element, in other place in the same time I can't read another? I ask to respond, whether the pure sine curve is visible at you on a graphics?

[crossrulz]

This is the very definition of a race condition.  When you have multiple places reading and writing, whoever is last wins.  You are losing data.

So the real question is what exactly are you trying to do?