[lammps-users] Roundoff error?

I'm having a tiny bit of trouble with setting up a geometry, I think it is due to round off error. Here's my setup:
lattice bcc 2.855300000 orient x 1 1 -2 orient y 1 1 1 orient z 1 -1 0 spacing 2.44948974278317809 .8660254037844386467637 1.414213562373095049
region main block 0.0 4.0 0.0 5.0 0.0 14.0
create_box 1 main
create_atoms 1 region main
I've set the spacings to be the natural lattice spacing in the specific directions, so that the integer region commands will produce a correct periodic lattice. However, when I run lammps, I'm only getting 1640 atoms, and I think there ought to be 1680. Please look at http://www.prism.gatech.edu/~egillilan3/Screenshot.gif. This is an image of the xz plane... you can see random atoms missing from the lattice. I'm not sure what could be causing this but round off error. Is there anything I can do? Thank you!


If it's a round-off issue, you should be able to tweak your values and get
it to work - i.e. either the spacing or box size.