When more than 32 groups need to be defined, how to find alternatives?

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1

Dear,

I’m running lammps in a Windows system. (Version: LAMMPS 64-bit 19Sep2019-MPI)
There is an interface that consists of an upper and a lower layer. When an in-plane
rotation motion (around the center of the face) is applied to the upper layer, the interfacial
torque is generated due to the vdW force.

I want to calculate the torque but there are no commands available. The most straightforward
way is to calculate the torque of each atom (in upper layer) and then sum them up. In this way,
I need to define each atom (in the upper layer) as a separate group, then use “compute group/group”
command for each defined group. Due to the constraint, I can only output the data of no more than 32
groups in a single simulation. However, the total number of atoms (groups) far exceeds 32 (~800 groups),
which means I have to repeat the simulation many times to extract the full data. This process is very
time-consuming. So, is there any other way？

Best.

2

Dear,

I’m running lammps in a Windows system. (Version: LAMMPS 64-bit 19Sep2019-MPI)
There is an interface that consists of an upper and a lower layer. When an in-plane
rotation motion (around the center of the face) is applied to the upper layer, the interfacial
torque is generated due to the vdW force.

I want to calculate the torque but there are no commands available.

no commands available??
what about compute torque/chunk https://lammps.sandia.gov/doc/compute_torque_chunk.html ?
or the torque group function for equal style variables https://lammps.sandia.gov/doc/variable.html ?

The most straightforward

no, this is the most inefficient, complex and convoluted way i could imagine.