# improper_style zero command

## Syntax

``` LAMMPS
improper_style zero [nocoeff]
```

## Examples

``` LAMMPS
improper_style zero
improper_style zero nocoeff
improper_coeff *
```

## Description

Using an improper style of zero means improper forces and energies are
not computed, but the geometry of improper quadruplets is still
accessible to other commands.

As an example, the [compute improper/local](compute_improper_local)
command can be used to compute the chi values for the list of
quadruplets of improper atoms listed in the data file read by the
[read_data](read_data) command. If no improper style is defined, this
command cannot be used.

The optional *nocoeff* flag allows to read data files with a
ImproperCoeff section for any improper style. Similarly, any
improper_coeff commands will only be checked for the improper type
number and the rest ignored.

Note that the [improper_coeff](improper_coeff) command must be used for
all improper types, though no additional values are specified.

## Restrictions

> none

## Related commands

none

[improper_style none](improper_none)

## Default

none