[lammps-users] Lammps-User

Dear professor,

There displays an error when an NPT simulation is run, the details are:
LAMMPS (23 Aug 2010)
Scanning data file …
4 = max bonds/atom
6 = max angles/atom
Reading data file …
orthogonal box = (-3.3562 -3.181 -3.2099) to (26.4202 26.9708 26.1994)
1 by 1 by 1 processor grid
1388 atoms
960 bonds
688 angles
Finding 1-2 1-3 1-4 neighbors …
4 = max # of 1-2 neighbors
3 = max # of 1-3 neighbors
3 = max # of 1-4 neighbors
4 = max # of special neighbors
1388 atoms in group all
1128 atoms in group water
260 atoms in group methane
Finding SHAKE clusters …
0 = # of size 2 clusters
0 = # of size 3 clusters
0 = # of size 4 clusters
376 = # of frozen angles
PPPM initialization …
G vector = 0.30131
grid = 25 25 24
stencil order = 5
RMS precision = 7.38705e-06
brick FFT buffer size/proc = 38148 15000 17340
Setting up run …
Memory usage per processor = 14.4062 Mbytes
Step Temp Press Volume TotEng
0 356.69634 -nan 26404.024 6.5705214e+53
ERROR: Out of range atoms - cannot compute PPPM
The attached are input and data files.
I have referred to the manual, it says there are probably two reasons causing this problem: one is missing pairwise interaction, and the other is that an atom has moved far outside a processor’s sub-domain or even the simulation box, which indicates bad physics,e.g. due to highly overlapping atoms, too large a timestep, etc.
I still have no notions how to correct my input file. Could you give me some instructions?
Best
Tang

in.ch4 (1.25 KB)

data2.data (135 KB)

At time 0, the pressure is NaN which indicates
the forces for your initial config are bad. E.g. due
to (nearly) overlapping atoms. This will lead
to immediate bad dynamics, hence the error.

So you need to examine/fix your initial configuration.

Steve

2011/1/2 tlx0509236.happy <[email protected]>: