# fix nve/body command

## Syntax

    fix ID group-ID nve/body

-   ID, group-ID are documented in [fix](fix) command
-   nve/body = style name of this fix command

## Examples

``` LAMMPS
fix 1 all nve/body
```

## Description

Perform constant NVE integration to update position, velocity,
orientation, and angular velocity for body particles in the group each
timestep. V is volume; E is energy. This creates a system trajectory
consistent with the microcanonical ensemble. See the [Howto
body](Howto_body) page for more details on using body particles.

This fix differs from the [fix nve](fix_nve) command, which assumes
point particles and only updates their position and velocity.

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

No information about this fix is written to [binary restart
files](restart). None of the [fix_modify](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](Howto_output). No
parameter of this fix can be used with the *start/stop* keywords of the
[run](run) command. This fix is not invoked during [energy
minimization](minimize).

## Restrictions

This fix is part of the BODY package. It is only enabled if LAMMPS was
built with that package. See the [Build package](Build_package) page for
more info.

This fix requires that atoms store torque and angular momentum and a
quaternion as defined by the [atom_style body](atom_style) command.

All particles in the group must be body particles. They cannot be point
particles.

## Related commands

[fix nve](fix_nve), [fix nve/sphere](fix_nve_sphere), [fix
nve/asphere](fix_nve_asphere)

## Default

none