[lammps-users] Rv: Re: fix wall/reflect command

Dear Sir/Madam,

dear luis,

I am a new LAMMPS user and I am having troubles with the
implementation of a reflective wall in my code. The input script is
shown below for your convenience. I have read the manual and the
documentation regarding the fix wall/reflect command but I still don’t
understand why every time I try to run an error pops up and does not
allow me to run my simulation. I tried to search on the documentation

that is most likely because your input does not correspond
to the syntax of the command as it is currently implemented
and documented in the online documentation.

please make sure that you always use the syntax that matches
the version of lammps that you are using. if you want help
from the mailing list, that typically means that you should
make sure that you have the latest patchlevel compiled.

and on the web examples that uses this command but I have not had any
success. Would it be possible for you to tell what is wrong in my
input script? Also, would you be able to provide me with some basic
examples that shows how to implement this command on an input script?

there _are_ examples in the online documentation:

you input has altogether three problems:

1) you need to set a non-periodic boundary for
reflective walls. so in your case you need to
set: boundary f f f

2) you need to use the correct syntax for the fix:

fix 2 all wall/reflect xlo -$L xhi $L ylo -$L yhi $L zlo -$L zhi $L


fix 2 all wall/reflect xlo EDGE xhi EDGE ylo EDGE yhi EDGE zlo EDGE
zhi EDGE

3) your fix nvt syntax is wrong, too. correct is:
fix 1 all nvt temp $T $T 0.005

(btw: the time constant of the thermostat is awfully short).


argon_module.in (2.29 KB)

log.lammps (2.42 KB)

I ran your script and it works fine. This may be an issue with the Windows executable. Also, you should check for problems in the offending input line (invisible characters, tabs, etc.). Try retyping it before the fix nvt command.

As stated on the bug fixes/new features page, the PDF file is not
updated every time LAMMPS is patched, since it’s a large file.
The HTML doc pages are updated for each patch. I would use
the HTML pages to stay current.