https://github.com/pyiron/lammpsparser
Parser for LAMMPS input and output files.
https://github.com/pyiron/lammpsparser
Last synced: 3 months ago
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Parser for LAMMPS input and output files.
- Host: GitHub
- URL: https://github.com/pyiron/lammpsparser
- Owner: pyiron
- License: bsd-3-clause
- Created: 2023-02-28T02:11:46.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2026-03-02T20:08:27.000Z (4 months ago)
- Last Synced: 2026-03-02T23:36:55.821Z (4 months ago)
- Language: Python
- Homepage:
- Size: 1.69 MB
- Stars: 3
- Watchers: 7
- Forks: 5
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Codeowners: .github/CODEOWNERS
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README
# lammpsparser
[](https://github.com/pyiron/lammpsparser/actions/workflows/pipeline.yml)
[](https://codecov.io/gh/pyiron/lammpsparser)
[](https://mybinder.org/v2/gh/pyiron/lammpsparser/main?urlpath=%2Fdoc%2Ftree%2Fnotebooks%2Fexample.ipynb)
The `lammpsparser` packages provides primarily two functions. A `write_lammps_structure()` function to write an `ase.atoms.Atoms`
structure to an LAMMPS data file and a `parse_lammps_output_files()` function to parse the `log.lammps`, `dump.out` and
`dump.h5` files from the LAMMPS `thermo` and `dump` commands.
## Installation
The `lammpsparser` package is distributed via both [pypi](https://pypi.org/project/lammpsparser/):
```
pip install lammpsparser
```
and [conda-forge](https://anaconda.org/conda-forge/lammpsparser):
```
conda install -c conda-forge lammpsparser
```
## Write LAMMPS structure
The `write_lammps_structure()` function is designed to write an `ase.atoms.Atoms` structure to an LAMMPS data file:
```python
from lammpsparser import write_lammps_structure
write_lammps_structure(
structure,
potential_elements,
units="metal",
file_name="lammps.data",
working_directory=None,
)
```
The `structure` parameter refers to the `ase.atoms.Atoms` structure and the `potential_elements` refers to the list of
elements implemented in the specific interatomic potential. For example the [NiAlH_jea.eam.alloy](https://github.com/lammps/lammps/blob/develop/potentials/NiAlH_jea.eam.alloy)
potential implements the elements `Ni`, `Al` and `H`, so when writing a structure for a simulation with this potential
the `potential_elements=["Ni", "Al", "H"]`. It is important to maintain the order of the elements as LAMMPS internally
references the elements based on their index, starting from one. The `units` parameter refers to the LAMMPS internal
[units](https://docs.lammps.org/units.html) to convert the `ase.atoms.Atoms` object which is defined in Angstrom to the
length scale of the LAMMPS simulation. Finally, `file_name` parameter and the current working directory `working_directory`
parameter are designed to select the location where the LAMMPS structure should be written. With the default parameters
the LAMMPS structure is written in the `lammps.data` file in the current directory.
## Parse LAMMPS output
In addition to writing the LAMMPS input structure `lammpsparser` also provide the `parse_lammps_output_files()` function
to parse the LAMMPS output files, namely the `log.lammps`, `dump.out` and `dump.h5` files:
```python
from lammpsparser import parse_lammps_output_files
parse_lammps_output_files(
working_directory,
structure,
potential_elements,
units="metal",
dump_h5_file_name="dump.h5",
dump_out_file_name="dump.out",
log_lammps_file_name="log.lammps",
)
```
In analogy to the `write_lammps_structure()` function the `working_directory` parameter refers to the directory which
contains the output files. The `structure` parameter reefers to the `ase.atoms.Atoms` object which should be used as
template to parse the structure from the dump files. This structure is again required as LAMMPS internally references
elements only by an index, so the template structure is required to map the elements from the interatomic potential back
to the elements of the `ase.atoms.Atoms` object. In the same way the `potential_elements` refers to the list of
elements implemented in the specific interatomic potential. The `units` parameter refers to the LAMMPS internal
[units](https://docs.lammps.org/units.html) to convert the `ase.atoms.Atoms` object which is defined in Angstrom to the
length scale of the LAMMPS simulation. Finally, the parameters `dump_h5_file_name`, `dump_out_file_name` and `log_lammps_file_name`
refer to the output file names.
For the `dump.out` file the following LAMMPS `dump` command should be added to the LAMMPS input file:
```
dump 1 all custom 100 dump.out id type xsu ysu zsu fx fy fz vx vy vz
dump_modify 1 sort id format line "%d %d %20.15g %20.15g %20.15g %20.15g %20.15g %20.15g %20.15g %20.15g %20.15g"
```
For the `log.lammps` file the following LAMMPS `thermo` command should be added to the LAMMPS input file:
```
thermo_style custom step temp pe etotal pxx pxy pxz pyy pyz pzz vol
thermo_modify format float %20.15g
thermo 100
```
## Usage
Currently, the `lammpsparser` parser is primarily used in the [pyiron_atomistics](https://github.com/pyiron/pyiron_atomistics)
package and its successor the [atomistics](https://github.com/pyiron/atomistics) package to provide a simple LAMMPS
parser. It only depends on `ase`, `numpy`, `pandas` and `scipy` and has an optional dependency on `h5py` to parse the
LAMMPS [h5md](https://docs.lammps.org/dump_h5md.html) format.