[lammps-users] Pair style hybrid with gran/hooke/history

As Ahmed says, you can't do this with pair hybrid, with any potential,
i.e. use it twice. The gran hooke/history potential would have
to be extended itself to allow different params for different
atom types. No one has ever wanted to do that before.

Steve, this is what everybody does in DEM. That's the reason why I modified
the granular pair styles in LIGGGHTS in a way that calculates kn, kt,
gamman, gammat for each contact differently