getting result nan in output file

Dear lammps users,

In my code, I am getting nan in output. what I need to change the program so I can get results.

code

newton off

— Introduction —

print “-------------------bnnt Simulation -------------------”
print “Written By: Vijay Choyal”
print “Date: Jan 19, 2015”

— Atom and Bond Definition —

— Basic input parameters —

units metal # mass=grams/mole, distance=Angstroms,

time=picoseconds

energy=eV, force=eV/Angstrom, temperature=Kelvin,

pressure=bars, charge=multiple of electron charge

dimension 3 # 3D imensions
boundary p p p # periodic along x,y, and z axes
atom_style atomic # store coordinates, velocities, atom IDs and types.

atom_modify map hash

read_data b_10_10_1.data

pair_style tersoff/gpu
pair_coeff * * BNC.tersoff B N

Armchair m=5, n=5, L=5

group ring_fixed id 1 335 669 1003 1335 1663 1991 2319 2647 2976 #Zmax
group ring_rotate id 333 667 1001 1333 1661 1989 2317 2645 2974 3306 #Zmin
group ring_point id 1497 #X=6.918, Y=-0.002 (Z=107)

group others subtract all ring_fixed ring_rotate

Dear lammps users,

In my code, I am getting nan in output. what I need to change the program
so I can get results.

​MD follows the GI-GO principle (garbage in​, garbage out), the MD program
will just do what you ask it to do.
it is your task to make certain, that this is following meaningful physics.
nobody will do that for you.
consider using LAMMPS like driving a car. we provide you with the car, but
you have to make sure you keep driving on the road, follow the rules and do
not hit other vehicles, objects or people.

in many cases you can see that you are doing something non-physical (e.g.
moving atoms on top of each other) through visualizing your simulation.
often people overlook the impact of periodic boundaries in these cases.

axel.