|
1 | | -# nomad-examples [](https://doi.org/10.6084/m9.figshare.19319783.v2) |
| 1 | +# nomad-examples [](https://doi.org/10.6084/m9.figshare.19319783.v3) |
2 | 2 |
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3 | 3 | Examples of using the Novel Materials Discovery (NOMAD) database, especially downloading all chemical formulas. |
| 4 | + |
| 5 | +### Installation |
| 6 | +Clone or download the repository. To clone: |
| 7 | +```bash |
| 8 | +git clone https://github.com/sparks-baird/nomad-examples.git |
| 9 | +cd nomad-examples |
| 10 | +``` |
| 11 | + |
| 12 | +Install the dependencies, e.g. via: |
| 13 | +```bash |
| 14 | +pip install -r requirements.txt |
| 15 | +``` |
| 16 | + |
| 17 | +### Reproducer |
| 18 | +Use [all_formula_basic_metadata.py](all_formula_basic_metadata.py) to download the data from NOMAD and to do some basic processing. This might take somewhere around an hour. |
| 19 | + |
| 20 | +```bash |
| 21 | +python -m all_formula_basic_metadata.py |
| 22 | +``` |
| 23 | + |
| 24 | +Use [remove_duplicate_compositions.py](remove_duplicate_compositions.py) to process the chemical formulas down to a list of unique chemical compositions (represented as reduced formulas). This also might take around an hour. |
| 25 | + |
| 26 | +```bash |
| 27 | +python -m remove_duplicate_compositions.py |
| 28 | +``` |
| 29 | + |
| 30 | +### Data Descriptions |
| 31 | +The data is available via figshare [DOI: 10.6084/m9.figshare.19319783.v3](https://doi.org/10.6084/m9.figshare.19319783.v3) and was downloaded on 2022-03-07. There are four files available: `all-formula.csv`, `unique-formula.csv`, `unique-reduced-formula.csv`, and `bad-formula.csv`. There are `11680557`, `764431`, `695612`, and `15` rows for each of these files, respectively. Descriptions are given below. |
| 32 | + |
| 33 | +#### `all-formula.csv` |
| 34 | +[`all-formula.csv`](https://figshare.com/ndownloader/files/34313849) contains two columns: `calc_id` (Calculation ID) and `formula` (Chemical Formula). These were restricted to VASP DFT calculations, and do not include noble gases nor radioactive elements. Some calculation IDs have missing chemical formulas. |
| 35 | + |
| 36 | +#### `unique-formula.csv` |
| 37 | +The list has also been filtered down to unique (non-reduced) chemical formulas in [`unique-formula.csv`](https://figshare.com/ndownloader/files/34313978) along with the `calc_id` for each unique formula. No structural information is included directly in this data. |
| 38 | + |
| 39 | +#### `unique-reduced-formula.csv` |
| 40 | +REALLY, what you're probably most interested in is [`unique-reduced-formula.csv`](https://figshare.com/ndownloader/files/34439036) because it is the most curated and is directly usable with e.g. `pymatgen`. This contains three columns: calc_id, reduced_formula, and factor which correspond to the Calculation ID, the reduced formula (e.g. Si2O4 --> SiO2), and the factor (e.g. for Si2O4 --> SiO2 the factor is 2). The formulas were first parsed via the [`pymatgen.core.Composition`](https://pymatgen.org/pymatgen.core.composition.html#pymatgen.core.composition.Composition) class. |
| 41 | + |
| 42 | +#### `bad-formula.csv` |
| 43 | +Finally, [`bad-formula.csv`](https://figshare.com/ndownloader/files/34439039) contains the formulas that were skipped during processing (i.e. not successfully processed with [`pymatgen.core.Composition`](https://pymatgen.org/pymatgen.core.composition.html#pymatgen.core.composition.Composition) for various reasons comprising 15 in total). |
| 44 | + |
| 45 | +### Future Work |
| 46 | +Downloading all of the crystal structures and reducing this to a list of unique _phases_ each with a CIF file. |
| 47 | + |
| 48 | +### Issues |
| 49 | +See something missing? Please don't hesitate to [drop me a note in issues](https://github.com/sparks-baird/nomad-examples/issues/new/choose). |
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