per atom vector based on nearest neighbor average

Dear Lammps Users,
I want to apply an additional force on few particle using addforce. Added force will depend on the average orientation of the nearest neighbors which are ellipsoid.
I was thinking to use “compute chunk/atom” command to define cluster of the nearest neighbors for all particles and then to define addforce components by taking average fover each cluster. However, chunk/atom does not seem to provide option to include nearest neighbor only cluster.
I will appreciate if someone can suggest other ways to add this kind of force this in my simulation.


This sounds like a new pair style or a new fix (with a post_force() method).

You’d use a neighbor list, and find nearby particles in it

and compute forces. There’s nothing in LAMMPS that will

automatically do this for a new model you’re devising.