units in centro/atom command

Dear all,

I am trying to understand the units of the output produced by the centro/atom command when axes = No (default value) and the number N is explicitly given by the user instead of specifying the keywords “fcc” or “bcc”. According to the equation provided in the manual, the CS parameter has units of squared length. In the “Output Info” section is written that “The centrosymmetry values are unitless values >= 0.0”. How is the normalization taking place in LAMMPS? I noticed that in the reference publications, the CS parameter is reported also in squared length units such as Angstromg ^2.


The doc page for compute centro/atom also discusses normalization
at the very bottom. That example is for Au so if you use its
lattice constant you should see how the normalized vs unnormalized
values compare. If that still doesn’t answer your Q, I suggest
you look in the source code. The CS calculation itself is
not complicated once you have the right set of neighbors
to loop over.