I was hoping someone might have some ideas about why I’m seeing some strange behavior in my locally modified version of LAMMPS. My modifications work as desired when applied to 10Nov05, but not 29Nov06.
The local modifications which might be relevant are 1) I’m using a custom fix, “FixAxialStrain” which is closely modeled on “FixUniaxial” 2) I’m using a custom bonded (breakable) interaction, “BondLJSmooth” which is closely modeled on the breakable bonded interaction “BondQuartic”. I won’t post code for the latter, since it is so close to BondQuartic, but, that said, I have not reproduced the anomalies with BondQuartic.
I noticed that domain.cpp had many modifications from 10Nov05 to 27Nov06 and suspect that these changes might conflict with my “FixAxialStrain” fix.
The behavior is as follows. After running for 6403 timesteps, runs using both 10Nov05 (plus my local changes) and 27Nov06 (plus my local changes) are identical (with respect to global scalars like Eng_vdwl, KineticEnergy, Lx,Ly, etc). At step 6404, the 27Nov06 version reports “Bond atoms missing” and exits, while the 10Nov05 is perfectly happy and keeps on going.
If I hack “neigh_bond.cpp” to make things more forgiving and change
fix_axial_strain.cpp (3.36 KB)