# compute smd/tlsph/strain command

## Syntax

    compute ID group-ID smd/tlsph/strain

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

## Examples

``` LAMMPS
compute 1 all smd/tlsph/strain
```

## Description

Define a computation that calculates the Green-Lagrange strain tensor
for particles interacting via the Total-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 of vectors (tensors),
which can be accessed by any command that uses per-particle values from
a compute as input. See the [Howto output](Howto_output) doc page for an
overview of LAMMPS output options.

The per-particle tensor values will be given dimensionless. See
[units](units).

The per-particle vector has 6 entries, corresponding to the xx, yy, zz,
xy, xz, yz components of the symmetric strain tensor.

## 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 quantity will be computed only for particles which interact with
the Total-Lagrangian SPH pair style.

## Related commands

[smd/tlsph/strain/rate](compute_smd_tlsph_strain_rate),
[smd/tlsph/stress](compute_smd_tlsph_stress)

## Default

none