---
# pretty_name: "" # Example: "MS MARCO Terrier Index"
tags:
- pyterrier
- pyterrier-artifact
- pyterrier-artifact.sparse_index
- pyterrier-artifact.sparse_index.pisa
task_categories:
- text-retrieval
viewer: false
---

# fever.pisa

## Description

A PISA index for the Fever dataset

## Usage

```python
# Load the artifact
import pyterrier as pt
index = pt.Artifact.from_hf('pyterrier/fever.pisa')
index.bm25() # return a BM25 retriever
```

## Benchmarks

`fever/dev`

| name   |   nDCG@10 |   R@1000 |
|:-------|----------:|---------:|
| bm25   |    0.6425 |   0.96   |
| dph    |    0.6831 |   0.9604 |

`fever/test`

| name   |   nDCG@10 |   R@1000 |
|:-------|----------:|---------:|
| bm25   |    0.6305 |   0.9532 |
| dph    |    0.6716 |   0.9573 |


## Reproduction

```python
import pyterrier as pt
from tqdm import tqdm
import ir_datasets
from pyterrier_pisa import PisaIndex
index = PisaIndex("fever.pisa", threads=16)
dataset = ir_datasets.load('beir/fever')
docs = ({'docno': d.doc_id, 'text': d.default_text()} for d in tqdm(dataset.docs))
index.index(docs)
```

## Metadata

```
{
  "type": "sparse_index",
  "format": "pisa",
  "package_hint": "pyterrier-pisa",
  "stemmer": "porter2"
}
```