compute sph/rho/atom command


compute ID group-ID sph/rho/atom
  • ID, group-ID are documented in compute command

  • sph/rho/atom = style name of this compute command


compute 1 all sph/rho/atom


Define a computation that calculates the per-atom SPH density for each atom in a group, i.e. a Smooth-Particle Hydrodynamics density.

The SPH density is the mass density of an SPH particle, calculated by kernel function interpolation using “pair style sph/rhosum”.

See this PDF guide to using SPH in LAMMPS.

The value of the SPH density will be 0.0 for atoms not in the specified compute group.

Output info

This compute calculates a per-atom vector, which can be accessed by any command that uses per-atom values from a compute as input. See the Howto output page for an overview of LAMMPS output options.

The per-atom vector values will be in mass/volume units.


This compute is part of the SPH package. It is only enabled if LAMMPS was built with that package. See the Build package page for more info.