compute rigid command — LIGGGHTS v3.X documentation

# compute rigid command

# compute multisphere command

# compute multisphere/single command

## Syntax

    compute ID group-ID multisphere general_keyword general_values (or multisphere) property property_name
    compute ID group-ID multisphere/single id id_ms general_keyword general_values (or multisphere) property property_name
    compute ID group-ID rigid general_keyword general_values (or multisphere) property property_name

- ID, group-ID are documented in compute command
- id = obligatory keyword for style multisphere/single
- id_ms = multisphere id which command applies to for style multisphere/single
- property = obligatory keyword
- general_keywords general_values are documented in compute
- property_name = xcm or vcm or fcm or torque or quat or angmom or omega or density or type or id or masstotal or inertia or ex_space or ey_space or ez_space

    xcm = body position (based on center of mass) (3 values)
    vcm = body velocity (based on center of mass) (3 values)
    fcm = body force (based on center of mass) (3 values)
    torque = body torque (based on center of mass) (3 values)
    quat = body quaternion (based on center of mass) (4 values)
    angmom = body angular momentum (based on center of mass) (3 values)
    omega = body angular velocity (based on center of mass) (3 values)
    density = body density (1 value)
    atomtype = atom type (material type) of the rigid body (1 value)
    clumptype = multi-sphere type as defined in fix paticleteplate/multisphere (1 value)
    id_multisphere = body id (1 value)
    masstotal = body mass (1 value)
    inertia = body intertia (based on center of mass, around ex_space, ey_space, ez_space) (3 values)
    ex_space, ey_space, ez_space = eigensystem of the body (based on center of mass) (3 values each)

## Examples

    compute xcm all multisphere property xcm

## Description

Define a computation that calculates properties of individual multi-sphere bodies (clumps) in the similation that were defined via fix particletemplate/multisphere

For style multisphere, data of all multisphere bodies in the system is generated. The local data stored by this command is generated by looping over the all the bodies owned on a process.

For style multisphere/single, only data of the multisphere body with the given ID is generated.

Warning

the group-ID is ignored for this command, as group data is atom-based, not clump-based.

## Output info

For style multisphere, this compute calculates a local vector or local array depending on the length of the data (see above). The vector or array can be accessed by any command that uses local values from a compute as input. See this section for an overview of LIGGGHTS(R)-PUBLIC output options.

Likewise, for style multisphere/single, this compute calculates a global scalar or vector depending on the length of the data (see above).

## Restrictions

Can only be used together with a granular pair style. For accessing particle-wall contact data, only mesh walls can be used.

## Related commands

dump local, compute property/local

Default: none