Problem with read_dump in triclinic mode

Hi everyone,

I’m trying to continue a simulation that has an output as dump files. It’s a sheared triclinic box under constant shear stress.

I make use of read_dump command and reset_timestep 0, so the first new dump file (number 0) should be identical to the old dump file that LAMMPS read (the dump command is identical to the old one).

The problem is that there is a difference between the files that cause everything go wrong. I found that the difference that changes everything is this:

Instead of ylo(new)=ylo(old) I get ylo(new)=ylo(old)+yz
And instead xhi I get xhi+xy+xz.

These two changes actually expand my box all the sudden, so density drops, temperature changes (previously equilibrated at NPT), stresses change, and all of that due to a wrong setting of box dimensions during read_dump execution.

Here are the headings of the two dump files:

ITEM: TIMESTEP
10000
ITEM: NUMBER OF ATOMS
32032
ITEM: BOX BOUNDS xy xz yz pp pp pp
3.25706 103.297 0.880569
-15.5604 77.5153 19.7655
-0.0428689 84.2206 -13.248

ITEM: TIMESTEP
0
ITEM: NUMBER OF ATOMS
32032
ITEM: BOX BOUNDS xy xz yz pp pp pp
3.25706 123.943 0.880569
-28.8084 77.5153 19.7655
-0.0428689 84.2206 -13.248

Thanks for your help in advance,
Eyal.

Probably a bug - I'll take a look at it ...

Steve

So I can't reproduce this. Attached are 2 input scripts
which you can run one after the other. They produce 2 dump
files. The box bounds on steps 300,400,500 match in both.
And the dynamics from the restarted run versus the continue
run is the same (modulo small round-offs).

I tried a couple different fix deform modes (see the input files)
and they still match. Can you adjust the fix deform tilt options
to get a case like yours where the read-in box is messed up?

You should also try running your problem with the most current
LAMMPS in case the bug has already been fixed.

Steve

in.lj (527 Bytes)

in.lj.restart (553 Bytes)