Tracking individual particles

[AdamFenton]

Hi Daniel,

I hope you are well. I'm trying to track individual particles from snapshot to snapshot through the simulation and am having some issues. I thought of using the particle ID numbers but these don't seem to be allocated to the same particles in one snapshot as they are in the next.
Is there something I am missing that enables the user to do something like this? Find the ID number of a particle at x1,y1,z1 at t = t_1 and then, using that ID number, find x2,y2,z2 of the particle at t = t2?

[dmentipl]

Hi @AdamFenton, sorry for the delayed response! I'm well, I hope you are too.

The particle id numbers in Plonk correspond to the array index of each particle as they are on file. I'm not 100% sure but I believe Phantom does keep all particles consistently "numbered" throughout a simulation. (Unless you mess with the snapshots and restart a calculation.)

I would be interested to know if you can make a small reproducible example of this issue and post it here. In my experience I've had no issues using the particle id consistently from snapshot to snapshot.

Perhaps I should make it clear somewhere in the docs or via a docstring that the particle id is not required to be consistent between snapshots, i.e. it's only guaranteed consistent within a snapshot.

What are your thoughts?

[AdamFenton]

Hi Daniel,

Apologies - I meant to close this issue almost as soon as I created it. I must have been doing something wrong somewhere. It all works as it should now.

All the best!
Adam