compute torque/chunk command


compute ID group-ID torque/chunk chunkID
  • ID, group-ID are documented in compute command

  • torque/chunk = style name of this compute command

  • chunkID = ID of compute chunk/atom command


compute 1 fluid torque/chunk molchunk


Define a computation that calculates the torque on multiple chunks of atoms.


This compute calculates the 3 components of the torque vector for eqch chunk, due to the forces on the individual atoms in the chunk around the center-of-mass of the chunk. The calculation includes all effects due to atoms passing through periodic boundaries.




The simplest way to output the results of the compute torque/chunk calculation to a file is to use the fix ave/time command, for example:

compute cc1 all chunk/atom molecule
compute myChunk all torque/chunk cc1
fix 1 all ave/time 100 1 100 c_myChunk[*] file tmp.out mode vector

Output info

This compute calculates a global array where the number of rows = the number of chunks Nchunk as calculated by the specified compute chunk/atom command. The number of columns = 3 for the 3 xyz components of the torque for each chunk. These values can be accessed by any command that uses global array values from a compute as input. See the Howto output doc page for an overview of LAMMPS output options.

The array values are “intensive”. The array values will be in force-distance units.