# compute smd/ulsph/effm command

## Syntax

``` LAMMPS
compute ID group-ID smd/ulsph/effm
```

-   ID, group-ID are documented in [compute](compute) command
-   smd/ulsph/effm = style name of this compute command

## Examples

``` LAMMPS
compute 1 all smd/ulsph/effm
```

## Description

Define a computation that outputs the effective shear modulus for
particles interacting via the updated Lagrangian SPH pair style.

See [this PDF guide](PDF/MACHDYN_LAMMPS_userguide.pdf)\_ to using Smooth
Mach Dynamics in LAMMPS.

## Output info

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

The per-particle vector contains the current effective per atom shear
modulus as computed by the [pair smd/ulsph](pair_smd_ulsph) pair style.

## Restrictions

This compute is part of the MACHDYN package. It is only enabled if
LAMMPS was built with that package. See the [Build
package](Build_package) page for more info. This compute can only be
used for particles which interact with the updated Lagrangian SPH pair
style.

## Related commands

[pair smd/ulsph](pair_smd_ulsph)

## Default

none