This command is a macro command that calculates the radial distance from a specified point to a set of points. That set of points can be defined using the standard LaGriT syntax of psets and range. If the specification for a set of points is omitted, the whole grid is used. The command operates on the current mesh object. This operation will (often) result in two attributes being added to the current mesh object. The first, a real named rdist, contains the radial distance from the point of interest. The second, an integer named ictrpt, contains an index that specifies the center point that was used for this calculation.

calc_rdist/x0,y0,z0/ [radius_index] / [pset,get,pset_name, ifirst,ilast,istride]

`x0,y0,z0`

are the coordinates of the center point used in the
calculation.

`radius_index`

is an optional integer. It serves as an index for a
specific center point. Its value is placed in the attribute
**ictrpt** throughout the range affected by the command. If it is not
specified, no changes are made to the attribute **ictrpt**. The
non-value for this attribute is 0 (i.e., if there is no radius
index, the value of **ictrpt** will be 0).

`calc_rdist`

takes specifies the range over which the command will be executed. If it is omitted, the whole
mesh is assumed.

```
calc_rdist/0,0,0
```

This command would calculate the distance from the origin to all points in the mesh, and place the values in rdist. It would not modify ictrpt in any way.

```
calc_rdist/ 1,0.25,1/ 10/ pset,get,big_sphere
```

This command would calculate the distance from the point 1,0.25,1
to all the points within the pset `big_sphere`

. It would place
those distances into rdist within that pset, and would replace the
value of `ictrpt`

with 10 within that pset as well.