distance command

fix property/atom/disttracer command

Syntax

fix id group property/atom/regiontracer/distance general_keyword general_value keyword value ...
fix id group property/atom/disttracer general_keyword general_value keyword value ...

ID, group-ID are documented in fix command
property/atom/regiontracer/distance = style name of this fix command
property/atom/disttracer = old style name (deprecated)
general_keyword/general_value pairs may be appended, as described in fix property/atom/regiontracer/time
zero or more keyword/value pairs may be appended to args

keyword = vector
  vector values = vx vy vz
    vx vy vz = vector along which distance is measured (normalized automatically)

Examples

fix tracer all property/atom/regiontracer/distance add_region tracereg
fix tracer all property/atom/regiontracer/distance add_region tracereg vector 0. 0. 1.

Description

Fix property/atom/regiontracer/distance computes the travelled distance of particles in the simulation domain and (optionally) a list of regions.

The details on how regions are treated can be found in fix property/atom/regiontracer/time

By default this fix computes the two norm (Euclidean distance) of the distance which particles travelled and averages it by the number of particles (in the simulation domain or region). If the vector keyword is specified with appropriate values vx, vy, vz, then the distance travelled in direction of this vector is computed (i.e. the absolute value of the dot product of delta x with the vector).

Restart, fix_modify, output, run start/stop

Information about this fix is written to binary restart files .

In case no regions are specified, this fix computes a per-atom scalar (the travelled distance of particles in the simulation domain) which can be accessed by various output commands. In case one or more optional regions are specified, this fix computes a per-atom array, where the first value for each particle is the travelled distance in the simulation domain and the following values are the travelled distance in the specified regions (in the order in which the regions are specified).

This fix computes a N-vector of distances, where N=1+number of regions specified, which can be accessed by various output commands. The vector components are the average travelled distance in the fix group for the whole simulation domain (first value) and for each region (following values). The order is following the order in which the regions are specified.

Restrictions

Currently, this feature does not support multi-sphere particles.

Default

None.