As I'm working with a points cloud, I need to iterate over the points IDs, so at this time, a repeat zone is (I guess) mandatory. I'm currently testing Accumulate Field node to understand what is the usage.

Your approch works but the problem I mentionned uses a volume of points. I also (later) add different masses and radius to points. At this time, a repeat zone is the more "readable" method that allows me to computer gravitaion between each points. Anyway, I keep your answer to make some tests. At this time, I'm not sure hwo to understand how the "Accumulate field" works, I'm currently testing :)

I don't know how this node works ;), I will check the documentation. Just one note: you don't need to sample index for the current point, the "position" attribute is the current one. At least, on my setup, it works. Thanks again for your advices, I'll check the attribute statistic.

Damned, I just found approximately the same solution using a repeat zone inside the simulation getting the domain count and sampling index. Thanks a lot for your answer, I'll take a look on your method to see if it's not more optimal.

Still woking in 3.4. Good method, no need to render one frame as in many others tutorials.