[lammps-users] Problem of adding new potential.

Hi all,

I am trying to add a potential. When I ran LAMMPS with that potential, some problems came out. It calculated only the number 0 step. The energy of following steps were all zero. And it stopped when next neighbor listing was proceeded. The screen output is shown as follow:

-bash-2.05b$ mpirun -n 8 lmp_foot <in.rgl
LAMMPS (22 Jun 2007)
Reading data file …
orthogonal box = (0 0 0) to (42.42 42.42 42.42)
2 by 2 by 2 processor grid
4000 atoms
Setting up run …
Memory usage per processor = 1.37737 Mbytes
Step Temp E_pair E_mol TotEng Press Volume
0 0 -14015.648 0 -14015.648 nan 72516.653
1 nan 0 0 nan nan 72516.653
2 nan 0 0 nan nan 72516.653
3 nan 0 0 nan nan 72516.653
4 nan 0 0 nan nan 72516.653

The potential I am trying to add is Rosato-Guillope-Legrand (RGL)-type force field, which is in the scheme of TB-SMA. I derived the rgl.cpp from pair_morse.cpp, adding a loop over neighbors for calculating phi[i], which is a per-atom array storing the environment effect on atom i. The parameters and functions are also modified.

In the input file in.rgl, neighbor_modify’s parameter is “delay 5”.

It seems the code fails to call the compute function and neighbor class.

The attachment includes rgl.cpp, rgl.h, and the input file.

Thanks for your help!


pair_rgl.cpp (11.5 KB)

pair_rgl.h (1.28 KB)

in.rgl (1.07 KB)

If you are getting a NAN pressure on timestep 0, it means your
forces are bad. Once that happens, all bets are off once you
time integrate.