[lammps-users] Atoms lost on parallel run

Dear Friends,
I am trying to get a slab of Copper to equilibrate at a constant temperature. It works fine in series, but when it gets to parallel compiling, the atoms are lost. I read through the mailing list and saw Steve’s suggestion that the problem occured because of the box dimensions did not allow expansion of the material. I made the neccessary changes to my code. But still, the problem persists.I am using the latest LAMMPS release (10th Jan 2010).Any inputs would be really helpful.

dimension 3
units metal
boundary p s p
atom_style atomic
timestep 0.001
lattice fcc 3.61

region box block 0 42.1 0 150 -5.5 5.5
create_box 5 box

mass 1 63.54
mass 2 63.54

mass 3 63.54
mass 4 63.54
mass 5 63.54

region lof block 5 26.1 0 1.1 -2.25 2.25
region lo-slab block 5 26.1 1.1 8.1 -2.25 2.25
create_atoms 1 region lo-slab
create_atoms 2 region lof

pair_style eam
pair_coeff * * /home/nandu/Desktop/lammps/potentials/Cu_u6.eam

group mobile region lo-slab
group mobile type 2
group boundary region lof
group boundary type 2

#minimize 0 0 1000 100000

compute new mobile temp
velocity mobile create 400 887723 temp new
velocity boundary set 0 0 0

fix 1 mobile nve
fix 2 mobile temp/rescale 50 300 300 0.05 0.5
fix 3 boundary setforce 0 0 0
fix_modify 2 temp new
thermo 50
thermo_modify temp new
log log.CU
dump 1 all atom 50 dump.Cu
run 200000

Regards,
Nandu Gopan

Dear Friends,
I am trying to get a slab of Copper to equilibrate at a constant
temperature. It works fine in series, but when it gets to parallel
compiling, the atoms are lost. I read through the mailing list and saw
Steve's suggestion that the problem occured because of the box
dimensions did not allow expansion of the material. I made the

actually, the most common reason for lost atoms is that
some of them are of too high kinetic energy due to high
potential energy of the initial geometry.

there are multiple options to handle this.
- run some minimization steps to remove excess potential energy
- use a shorter time step until the system is equilibrated
- update the neighbor lists more often

neccessary changes to my code. But still, the problem persists.I am

where?? what?

cheers,
   axel.