# compute momentum command

## Syntax

compute ID group-ID momentum

• ID, group-ID are documented in compute command

• momentum = style name of this compute command

## Examples

compute 1 all momentum


## Description

Define a computation that calculates the translational momentum of a group of particles.

The momentum of each particles is computed as m v, where m and v are the mass and velocity of the particle.

## Output info

This compute calculates a global vector (the summed momentum) of length 3. This value can be used by any command that uses a global vector value from a compute as input. See the Howto output doc page for an overview of LAMMPS output options.

The vector value calculated by this compute is “extensive”. The vector value will be in mass*velocity units.

## Restrictions

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

none