bart-squad2 / README.md
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---
language: "en"
---
# BART-Squad2
## Model description
BART for extractive (span-based) question answering, trained on Squad 2.0.
F1 score of 87.4.
## Intended uses & limitations
Unfortunately, the Huggingface auto-inference API won't run this model, so if you're attempting to try it through the input box above and it complains, don't be discouraged!
#### How to use
Here's a quick way to get question answering running locally:
```python
from transformers import AutoTokenizer, AutoModelForQuestionAnswering
tokenizer = AutoTokenizer.from_pretrained("Primer/bart-squad2")
model = AutoModelForQuestionAnswering.from_pretrained("Primer/bart-squad2")
model.to('cuda'); model.eval()
def answer(question, text):
seq = '<s>' + question + ' </s> </s> ' + text + ' </s>'
tokens = tokenizer.encode_plus(seq, return_tensors='pt', padding='max_length', max_length=1024)
input_ids = tokens['input_ids'].to('cuda')
attention_mask = tokens['attention_mask'].to('cuda')
start, end, _ = model(input_ids, attention_mask=attention_mask)
start_idx = int(start.argmax().int())
end_idx = int(end.argmax().int())
print(tokenizer.decode(input_ids[0, start_idx:end_idx]).strip())
# ^^ it will be an empty string if the model decided "unanswerable"
>>> question = "Where does Tom live?"
>>> context = "Tom is an engineer in San Francisco."
>>> answer(question, context)
San Francisco
```
(Just drop the `.to('cuda')` stuff if running on CPU).
#### Limitations and bias
Unknown, no further evaluation has been performed. In a technical sense one big limitation is that it's 1.6G 馃槵
## Training procedure
`run_squad.py` with:
|param|value|
|---|---|
|batch size|8|
|max_seq_length|1024|
|learning rate|1e-5|
|epochs|2|
Modified to freeze shared parameters and encoder embeddings.