[lammps-users] read_restart / read_data


I am having some trouble with the read_restart and read_data commands.

I have an input file whose last line is [ write_restart restart.100 ].
If I run a new input script with the line [ read_restart restart.100 ] the simulation runs fine.
If I run [ restart2data restart.100 restart.100.txt ] and then run an input script using
[ read_data restart.100.txt ] the simulation doesn't conserve energy and the kinetic energy increases without bound.

My system consists of 256 molecules, where each molecule is a 3-atom rigid body. I've seen the above problem before: when a rigid body is lying across a boundary, then the rigid body integrator fails. This problem can be by-passed by either keeping the nx ny nz flags in the read_data file so that the molecules are unwrapped properly, or by changing the positions of the atoms so that no unwrapping needs to take place.

I've done both tests.
1. The restart.1000.txt file contains the nx ny nz flags which tells LAMMPS how to unwrap the rigid bodies. But for some reason this system blows up (although the binary version of this file doesn't).

2. I've changed the positions of those rigid bodies that lie across boundaries so that they do not need to be unwrapped. This also results in a system that blows up in the same was as #1. The molecules whose positions have been corrected are 56, 136, 189, 196, 242. The values can be compared in restart.100.txt and corrected_restart.100.txt.

Attached is are my files in a .tar.gz file. I'd appreciate any input into this problem.

much thanks,

test.tar.gz (92.7 KB)