LAMMPS WWW Site - LAMMPS Documentation - LAMMPS Commands

### comm_style command

Syntax:

    comm_style style

- style = brick or tiled

Examples:

    comm_style brick
    comm_style tiled

Description:

This command sets the style of inter-processor communication of atom information that occurs each timestep as coordinates and other properties are exchanged between neighboring processors and stored as properties of ghost atoms.

For the default brick style, the domain decomposition used by LAMMPS to partition the simulation box must be a regular 3d grid of bricks, one per processor. Each processor communicates with its 6 Cartesian neighbors in the grid to acquire information for nearby atoms.

For the tiled style, a more general domain decomposition can be used, as triggered by the balance or fix balance commands. The simulation box can be partitioned into non-overlapping rectangular-shaped "tiles" or varying sizes and shapes. Again there is one tile per processor. To acquire information for nearby atoms, communication must now be done with a more complex pattern of neighboring processors.

Note that this command does not actually define a partitoining of the simulation box (a domain decomposition), rather it determines what kinds of decompositions are allowed and the pattern of communication used to enable the decomposition. A decomposition is created when the simulation box is first created, via the create_box or read_data or read_restart commands. For both the brick and tiled styles, the initial decomposition will be the same, as described by create_box and processors commands. The decomposition can be changed via the balance or fix balance commands.

Restrictions: none

Related commands:

comm_modify, processors, balance, fix balance

Default:

The default style is brick.