Hello,
I was following the LAMMPS example ELASTIC_T on GitHub. The original example uses a non-orthogonal cubic box, and I attempted to modify it to an orthogonal one. While I understand the error message, c44 is associated with the z-axis (numbered as 3). The calculations for c44 are present but I still get the error which left me confused.
Could you provide some guidance or clarify how to correctly adjust the example for an orthogonal box?
Thank you.
The two changes I made regarding the box are here :
elastic.in (2.0 KB)
displace.mod (1.9 KB)
you need these two to run :
potential.mod.txt (698 Bytes)
init.mod.txt (1.8 KB)
remove the txt in the name (for some reason wouldn’t let me upload them if there weren’t a txt )
lammps/stable_2Aug2023_update3
The error message means, that the variable C44 (note the spelling) was not defined and if I compare the scripts you provide against the originals then this is the case.
You are also incorrect in the geometry assessment because direction 4 is the yz tilt.
This is all very obvious and an indication that you have to significantly improve your debugging skills (and make the changes you do in smaller increments). Bottom line, if you modify posted scripts, you have to deal with the consequences yourself. It is not likely that somebody here will be interested to help you unless you have proof beyond doubt that you are exposing a genuine bug in LAMMPS itself.
In other words, do not immediately post the the forum whenever you encounter an error. This is not the purpose of this forum, and - as it has happened with others - your chance of getting any responses will drop if you continue to do it.