Hi All

I’m beginner in lammps , I’ve a question in wall/reflect command , is this command manner like maxwell specular-model? Or not!!? I run below code in lammps and see this error!!! can you help me? I do this simulation first without wall (that you see code) and once again I do this with define molecules as wall , at two code I see this error!!

Thank a lot

fix xwalls all wall/reflect ylo EDGE yhi EDGE

This command works fine when added to bench/in.lj
if you also set the y dimension to be non-periodic.

Which you haven't done. But you are getting a different
error. I am guessing you are not using the current
version of LAMMPS, which the doc pages are always for.