[lammps-users] Net force on intruder

Hi all,
I want to dump net force on intruder (big particle) due to granular particles(small particle). The intruder is moving in granular packing(small particles). Can I use fix group/group for this purpose? Please guide me in this regard.
Thanks in advance,

yes it can - I would read the doc page for compute group/group


Hi Steve,

yes it can - I would read the doc page for compute group/group
you mean “I would read or you would read”?

I mean you should read the doc page and
experiment with the command.


Dear Steve,
I did experiment with compute group/group command, but it can not work with pair granular. Can you suggest me another command which can compute forces on intruder(one particle) due to the other particles(small)?
Thanks for help,

Compute group/group doesn't work with granular potentials b/c
group/group assumes the potential can calculate the force
between 2 particles as a function of r. But granular forces
are more complicated - they include tangential forces, torque,
history effects, etc. Manybody forces also cannot be used
with compute group/group.

If you just want force on a single particle, due to all the
others, then why not just dump it into a dump file. It will
be the total force on that particle? Or you can access force
on a particle with many other commands: computes, variables, etc.