I'm doing a kuramoto style potential and I dont think I can use the same
method as EAM because that density propriety is calculated each time set
while I want the phase to be something that carries is altered each time set
but that the atom remembers the next one. I dont think I can do that
implementing that same comunication can I?
i don't know this model, so i cannot comment on the details. whether
data is retained or not and whether you need a forward or reverse
communication or both depends on those details.
in principle, per-atom data remains with atoms, until atoms are
exchanged between between processors during the neighbor list rebuild
which redistributes atoms into subdomains.
if you need your data to persist between time steps, you have to do
that kind of communication, which is part of atom styles or can be
provided via fix property/atom. question here is: how is this data
initialized at the beginning of the run? fix property/atom has
mechanisms for that.
whether you need reverse or forward communication or none of them,
depends on how and when you need to update this property, and whether
this is happening via an intermediate data (like type or number of
neighbors or some distance related property or ...) that is computed
for each pair, and whether you are using a half or a full neighbor
list (and whether you use newton on or newton off).
the issue is, that with a full neighbor list, each pair is processed
twice. with a half neighbor list each pair is processed only once with
the default newton on setting: this means if you update some parameter
based on a pair interaction, you have to communicate it back from
ghost atoms to its matching atoms. that is what the reverse
communication is for (which is a summation, it doesn't make sense
with the newton off setting, however, this reverse communication is
not needed, since in this case, all pairs where one atom is a ghost
atom are listed twice and thus you only store the local contribution.
in either case, if you have computed/updated a local property (doing
the outer loop only) and now need to update this to ghost atoms, then
you need to do a forward communication.
hope that clarifies matters some more. if you want further advice, you
have to provide a much more detailed description of the computations
and flow of control (and data) that you are attempting.