# supercon_tc — data file

## Usage

```bash
bash download.sh   # writes data.csv in this directory
```

Requires: `python3` (stdlib only — `csv`, `zipfile`, `io`, `urllib`).
No third-party packages needed. The script downloads the raw ZIP from the
UCI ML Repository, extracts `unique_m.csv`, keeps only the 77 elements with
non-zero fractions in at least one row, and writes `data.csv`. Runtime: ~15 s
on a typical connection.

`data.csv` is gitignored per the repo-wide rule
(`benchmarks/**/data/data.*` in `.gitignore`) — always rebuild locally with
this script. Only this `README.md` is kept in git.

## Source

| Field      | Value |
|------------|-------|
| Dataset    | SuperCon / NIMS superconductor database (via UCI ML Repository) |
| URL        | <https://archive.ics.uci.edu/static/public/464/superconductivty+data.zip> |
| License    | **unknown** (NIMS SuperCon database, publicly accessible, no explicit license) |
| Paper      | Hamidieh, K., *Computational Materials Science* **154**, 346–354 (2018) |
| DOI        | <https://doi.org/10.1016/j.commatsci.2018.07.052> |
| Retrieved  | 2026-04-22 |

The critical temperature values are experimentally measured from the NIMS
SuperCon database of inorganic superconductors. The element mole fractions
come directly from the chemical formula of each material (column `unique_m.csv`
in the original ZIP).

## Column layout

Column 0 is the output. Columns 1–77 are element mole fractions
(values are non-zero for at least one material; 9 noble-gas / unstable
elements dropped as all-zero: He, Ne, Ar, Kr, Xe, Pm, Po, At, Rn).

| Col | Name             | Units | Role   |
|-----|------------------|-------|--------|
| 0   | `critical_temp`  | K     | output |
| 1   | `frac_Ag`        | dimensionless | input  |
| 2   | `frac_Al`        | dimensionless | input  |
| 3   | `frac_As`        | dimensionless | input  |
| 4   | `frac_Au`        | dimensionless | input  |
| 5   | `frac_B`         | dimensionless | input  |
| 6   | `frac_Ba`        | dimensionless | input  |
| 7   | `frac_Be`        | dimensionless | input  |
| 8   | `frac_Bi`        | dimensionless | input  |
| 9   | `frac_Br`        | dimensionless | input  |
| 10  | `frac_C`         | dimensionless | input  |
| 11  | `frac_Ca`        | dimensionless | input  |
| 12  | `frac_Cd`        | dimensionless | input  |
| 13  | `frac_Ce`        | dimensionless | input  |
| 14  | `frac_Cl`        | dimensionless | input  |
| 15  | `frac_Co`        | dimensionless | input  |
| 16  | `frac_Cr`        | dimensionless | input  |
| 17  | `frac_Cs`        | dimensionless | input  |
| 18  | `frac_Cu`        | dimensionless | input  |
| 19  | `frac_Dy`        | dimensionless | input  |
| 20  | `frac_Er`        | dimensionless | input  |
| 21  | `frac_Eu`        | dimensionless | input  |
| 22  | `frac_F`         | dimensionless | input  |
| 23  | `frac_Fe`        | dimensionless | input  |
| 24  | `frac_Ga`        | dimensionless | input  |
| 25  | `frac_Gd`        | dimensionless | input  |
| 26  | `frac_Ge`        | dimensionless | input  |
| 27  | `frac_H`         | dimensionless | input  |
| 28  | `frac_Hf`        | dimensionless | input  |
| 29  | `frac_Hg`        | dimensionless | input  |
| 30  | `frac_Ho`        | dimensionless | input  |
| 31  | `frac_I`         | dimensionless | input  |
| 32  | `frac_In`        | dimensionless | input  |
| 33  | `frac_Ir`        | dimensionless | input  |
| 34  | `frac_K`         | dimensionless | input  |
| 35  | `frac_La`        | dimensionless | input  |
| 36  | `frac_Li`        | dimensionless | input  |
| 37  | `frac_Lu`        | dimensionless | input  |
| 38  | `frac_Mg`        | dimensionless | input  |
| 39  | `frac_Mn`        | dimensionless | input  |
| 40  | `frac_Mo`        | dimensionless | input  |
| 41  | `frac_N`         | dimensionless | input  |
| 42  | `frac_Na`        | dimensionless | input  |
| 43  | `frac_Nb`        | dimensionless | input  |
| 44  | `frac_Nd`        | dimensionless | input  |
| 45  | `frac_Ni`        | dimensionless | input  |
| 46  | `frac_O`         | dimensionless | input  |
| 47  | `frac_Os`        | dimensionless | input  |
| 48  | `frac_P`         | dimensionless | input  |
| 49  | `frac_Pb`        | dimensionless | input  |
| 50  | `frac_Pd`        | dimensionless | input  |
| 51  | `frac_Pr`        | dimensionless | input  |
| 52  | `frac_Pt`        | dimensionless | input  |
| 53  | `frac_Rb`        | dimensionless | input  |
| 54  | `frac_Re`        | dimensionless | input  |
| 55  | `frac_Rh`        | dimensionless | input  |
| 56  | `frac_Ru`        | dimensionless | input  |
| 57  | `frac_S`         | dimensionless | input  |
| 58  | `frac_Sb`        | dimensionless | input  |
| 59  | `frac_Sc`        | dimensionless | input  |
| 60  | `frac_Se`        | dimensionless | input  |
| 61  | `frac_Si`        | dimensionless | input  |
| 62  | `frac_Sm`        | dimensionless | input  |
| 63  | `frac_Sn`        | dimensionless | input  |
| 64  | `frac_Sr`        | dimensionless | input  |
| 65  | `frac_Ta`        | dimensionless | input  |
| 66  | `frac_Tb`        | dimensionless | input  |
| 67  | `frac_Tc`        | dimensionless | input  |
| 68  | `frac_Te`        | dimensionless | input  |
| 69  | `frac_Ti`        | dimensionless | input  |
| 70  | `frac_Tl`        | dimensionless | input  |
| 71  | `frac_Tm`        | dimensionless | input  |
| 72  | `frac_V`         | dimensionless | input  |
| 73  | `frac_W`         | dimensionless | input  |
| 74  | `frac_Y`         | dimensionless | input  |
| 75  | `frac_Yb`        | dimensionless | input  |
| 76  | `frac_Zn`        | dimensionless | input  |
| 77  | `frac_Zr`        | dimensionless | input  |

## Dataset statistics (after download)

- Rows: 21,263
- Columns: 78 (1 output + 77 element fraction inputs)
- Distinct elements: 77 (9 all-zero elements dropped: He, Ne, Ar, Kr, Xe, Pm, Po, At, Rn)
- Output range: [0.00021, 185.0] K (critical temperature)
- Output median: ~20.0 K
- Output mean: ~34.42 K
- No missing values (element fractions are 0.0 for absent elements)
- Tc == 0 rows: 0 (all rows have positive Tc)