is it necessary to use atom_style charge when using read_data and reaxFF?

Hi all,

I noticed something odd when I was running some reaxFF jobs.

Previously, I had been using the reaxFF potential from Mattsson et al. using a combination of the lattice command and the molecule command to create my atoms/molecules. When I use atom_style atomic, the simulation successfully runs.

Now, I am reading in atomic positions using a data file and finding that I get a Seg Fault when I use atom_style atomic but it works perfectly fine when I include charges in the data file and use atom_style charge.

Is this intentional or perhaps a bug? I thought I’d post this on the mailing list in case other users are stuck on this issue.

I’ve also added example input/data files.

Cheers,
Alex

input (390 Bytes)

input2 (390 Bytes)

data.in2 (220 Bytes)

data.in3 (212 Bytes)

Hi all,

I noticed something odd when I was running some reaxFF jobs.

Previously, I had been using the reaxFF potential from Mattsson et al. using
a combination of the lattice command and the molecule command to create my
atoms/molecules. When I use atom_style atomic, the simulation successfully
runs.

two comments:
- pair style reax is obsolete, please consider using reax/c instead.
(and reax/c will refuse to run when the atom style does not include
charges)
- reaxFF at its very core requires charges. it should be obvious from
reading the paper(s) describing it.

Now, I am reading in atomic positions using a data file and finding that I get a Seg Fault when I use atom_style atomic > but it works perfectly fine when I include charges in the data file and use atom_style charge.

If you have a data file that is formatted correctly for atom_style atomic and

crashes when using read_data, please post it and the simple input
script that reads it.

Steve

Dear Axel and Steve,

Thanks for the comments!

Axel, you’re right of course. I was just familiarizing myself with how to use the commands in lammps. But I will just stick with reax/c instead and explicitly set charges.

Steve, I’ve attached a tar with some simple test files. The input/data.in pair are the working ones (with atom style charge) and the input2/data.in2 are the seg faulting ones (with atom style atomic). In the latter case, here’s my output:

LAMMPS (10 Jan 2014)
using 1 OpenMP thread(s) per MPI task
Reading data file …
orthogonal box = (0 0 0) to (27.2303 31.3592 16.4406)
1 by 1 by 1 MPI processor grid
2 atoms
Setting up run …
[login4.stampede.tacc.utexas.edu:mpi_rank_0][error_sighandler] Caught error: Segmentation fault (signal 11)
Segmentation fault (core dumped)

Using the same data file (data.in2), I’ve gotten it to run by replacing the force field with a dummy tersoff potential.

Hope this helps,
Alex

reax_simple_example.tar (30 KB)