[lammps-users] Lammps output - Ave neighs/atom

Dear Lammps users,

I have a question regarding the statistics of pairwise interactions printed by Lammps. In the manual, the following example is given:

Total # of neighbors = 708282
Ave neighs/atom = 353.434

Ave special neighs/atom = 2.34032
Number of reneighborings = 42
Dangerous reneighborings = 2 

What does the second line stand for? I would have thought that it gives the average number of neighbors that each atom has, but from the number it seems like this is expressed in the next line (“Ave special neighs/atom” ?). I am using an older and modified version of Lammps where I observed an “Ave neighs/atom” of 440, while my each of the atom in my system should only have 4 neighbors. The “special” line is not printed. Is there any way to check that my coordination is 4 from the “Ave neighs/atom” number?

Thank you for help.


Someone please correct me if I am wrong but I believe 'Ave
neighs/atom' is the ratio of the total number of neighbors (in
neighboring lists) to the number to 'real' atoms. You can find the
definition in finish.cpp.


Neighborrs are pairwise interactions in the neighbor list
out to a distance force cutoff + neighbor skin.

Special neighbors have to do with excluded interactions
from the "special bonds" command.


I see. Thank you Steve and Zhun-Yong for your answers.


2010/4/15 Steve Plimpton <[email protected]>