[lammps-users] Lost atoms with some scale values in the lattice command(modified input)

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1

Dear LAMMPS Users,
The number of atoms changes with the same input except different scales(denoted as a) in the lattice command. I posted the problem just now, but a mistake was given in my input for the boundary command(not s s p, but p s p). Sorry for that.

dimension 3
units metal
boundary p s p
atom_style atomic
lattice fcc $a origin 0 0 0 orient x 1 1 -2 orient y 1 1 1 orient z 1 -1 0
region box block 0 3 0 1 0 3
create_box 1 box
create_atoms 1 box

if a=1,2,3,...or 3.625,3.635,3.675, the number is 192;
if a=3.615(lattice constant for Cu),3.665, the number is 190;
if a=3.605,3.645,3.655,3.695, the number is 191.

why are some atoms lost for some scale values?
Thank you for your time. Any help is appreciated.

Zhenhai Xu

2

Probably some round-off issue near the box edges. Can you viz and
tell which atom(s) are getting created vs non created?

Steve

3

Just posted a patch for this. It was a round-off issue.
Now, all the lattice values you tried give the same result,
generating 192 atoms, as they should.

Steve