[lammps-users] atom_style error

Dear Lammps users,

I am a beginner of Lammps, so it might be simple question..
I got an error:

ERROR: Invalid atom style

When I use condition in input script,

units real
atom_style angle

I changed atom_style, but I always got same error.
Would you please tell me how to fix it?
Thank you very much.

Best regards,
Nanako Takahashi

Atom style angle is in the MOLECULE package. If you
didn't build LAMMPS with that package, then you can't
use that command. The package is included by default.
See Section_start.html in the manual for info about packages.