# fix lb/pc command

## Syntax

fix ID group-ID lb/pc

• ID, group-ID are documented in the fix command

• lb/pc = style name of this fix command

## Examples

fix 1 all lb/pc


## Description

Update the positions and velocities of the individual particles described by group-ID, experiencing velocity-dependent hydrodynamic forces, using the integration algorithm described in Mackay et al.. This integration algorithm should only be used if a user-specified value for the force-coupling constant used in fix lb/fluid has been set; do not use this integration algorithm if the force coupling constant has been set by default.

Restart, fix_modify, output, run start/stop, minimize info:

No information about this fix is written to binary restart files. None of the fix_modify options are relevant to this fix. No global or per-atom quantities are stored by this fix for access by various output commands. No parameter of this fix can be used with the start/stop keywords of the run command. This fix is not invoked during energy minimization.

## Restrictions

This fix is part of the USER-LB package. It is only enabled if LAMMPS was built with that package. See the Build package doc page for more info.

Can only be used if a lattice-Boltzmann fluid has been created via the fix lb/fluid command, and must come after this command.