Using region keyword of cylinder, but obtaining block shape.

Dear All,

I’m trying to create a very simple cylinder nanowire using following input script. However, it is very strange that the output shows the nanowire possesses block shape, as shown in attached figure. Would anyone give me some explanation about such problem? Thanks in advance! I’m using lammps-1Jul11 version.

Best,
Junjie

-------------input script------------
units metal
boundary s s s

atom_style atomic
lattice fcc 3.615
region box cylinder x 0 0 5 -10 10
create_box 1 box
create_atoms 1 box

pair_style eam
pair_coeff * * Cu_u3.eam

neighbor 2.0 bin
neigh_modify delay 5

compute new3d all temp
velocity all create 3.0 5812775 temp new3d

fix 1 all nve
thermo 1
thermo_modify temp new3d

dump 1 all atom 100 dump.lammpstrj
dump 2 all cfg 100 dump.*.cfg id type xs ys zs
timestep 0.001
run 1

cylinder-block.jpg

Dear All,

I'm trying to create a very simple cylinder nanowire using following input
script. However, it is very strange that the output shows the nanowire
possesses block shape, as shown in attached figure. Would anyone give me
some explanation about such problem? Thanks in advance! I'm using

lammps doesn't create atoms outside the system box.

lammps-1Jul11 version.

Best,
Junjie

-------------input script------------
units metal
boundary s s s

atom_style atomic
lattice fcc 3.615
region box cylinder x 0 0 5 -10 10
create_box 1 box

here is the problem. you have to create a box
that _contains_ the cylinder. you are crating a
box that _is contained_ in the cylinder.

axel.

I think the error is that you used
create_atoms 1 box
which will put atoms in the entire simulation box (which
is always a box, not a cylinder).

If you used create_atoms 1 region box
then you would only create atoms inside
the cylinder (and also inside the simulation box).

You should really name your region something
other than box. It's confusing you.

Steve