---
license: mit
datasets:
- squad_v2
- squad
language:
- en
library_name: transformers
tags:
- question-answering
- squad
- squad_v2
- t5
- lora
- peft
model-index:
- name: sjrhuschlee/flan-t5-large-squad2
  results:
  - task:
      type: question-answering
      name: Question Answering
    dataset:
      name: squad_v2
      type: squad_v2
      config: squad_v2
      split: validation
    metrics:
    - type: exact_match
      value: 86.785
      name: Exact Match
    - type: f1
      value: 89.537
      name: F1
  - task:
      type: question-answering
      name: Question Answering
    dataset:
      name: squad
      type: squad
      config: plain_text
      split: validation
    metrics:
    - type: exact_match
      value: 85.998
      name: Exact Match
    - type: f1
      value: 91.296
      name: F1
  - task:
      type: question-answering
      name: Question Answering
    dataset:
      name: adversarial_qa
      type: adversarial_qa
      config: adversarialQA
      split: validation
    metrics:
    - type: exact_match
      value: 35.767
      name: Exact Match
    - type: f1
      value: 45.565
      name: F1
  - task:
      type: question-answering
      name: Question Answering
    dataset:
      name: squad_adversarial
      type: squad_adversarial
      config: AddOneSent
      split: validation
    metrics:
    - type: exact_match
      value: 75.322
      name: Exact Match
    - type: f1
      value: 79.327
      name: F1
  - task:
      type: question-answering
      name: Question Answering
    dataset:
      name: squadshifts
      type: squadshifts
      config: nyt
      split: test
    metrics:
    - type: exact_match
      value: 83.815
      name: Exact Match
    - type: f1
      value: 90.416
      name: F1
---

# flan-t5-large for Extractive QA

This is the [flan-t5-large](https://huggingface.co/google/flan-t5-large) model, fine-tuned using the [SQuAD2.0](https://huggingface.co/datasets/squad_v2) dataset. It's been trained on question-answer pairs, including unanswerable questions, for the task of Extractive Question Answering.

This model was trained using LoRA available through the [PEFT library](https://github.com/huggingface/peft).

NOTE: The <cls> token must be manually added to the beginning of the question for this model to work properly. It uses the <cls> token to be able to make "no answer" predictions. The t5 tokenizer does not automatically add this special token which is why it is added manually.

## Overview
**Language model:** flan-t5-large  
**Language:** English  
**Downstream-task:** Extractive QA  
**Training data:** SQuAD 2.0  
**Eval data:** SQuAD 2.0  
**Infrastructure**: 1x NVIDIA 3070  

## Model Usage

### Using Transformers
This uses the merged weights (base model weights + LoRA weights) to allow for simple use in Transformers pipelines. It has the same performance as using the weights separately when using the PEFT library.
```python
import torch
from transformers import(
  AutoModelForQuestionAnswering,
  AutoTokenizer,
  pipeline
)
model_name = "sjrhuschlee/flan-t5-large-squad2"

# a) Using pipelines
nlp = pipeline('question-answering', model=model_name, tokenizer=model_name)
qa_input = {
'question': f'{nlp.tokenizer.cls_token}Where do I live?',  # '<cls>Where do I live?'
'context': 'My name is Sarah and I live in London'
}
res = nlp(qa_input)
# {'score': 0.984, 'start': 30, 'end': 37, 'answer': ' London'}

# b) Load model & tokenizer
model = AutoModelForQuestionAnswering.from_pretrained(model_name)
tokenizer = AutoTokenizer.from_pretrained(model_name)

question = f'{tokenizer.cls_token}Where do I live?'  # '<cls>Where do I live?'
context = 'My name is Sarah and I live in London'
encoding = tokenizer(question, context, return_tensors="pt")
start_scores, end_scores = model(
  encoding["input_ids"],
  attention_mask=encoding["attention_mask"],
  return_dict=False
)

all_tokens = tokenizer.convert_ids_to_tokens(input_ids[0].tolist())
answer_tokens = all_tokens[torch.argmax(start_scores):torch.argmax(end_scores) + 1]
answer = tokenizer.decode(tokenizer.convert_tokens_to_ids(answer_tokens))
# 'London'
```

## Metrics

```bash
# Squad v2
{
    "eval_HasAns_exact": 85.08771929824562,
    "eval_HasAns_f1": 90.598422845031,
    "eval_HasAns_total": 5928,
    "eval_NoAns_exact": 88.47771236333053,
    "eval_NoAns_f1": 88.47771236333053,
    "eval_NoAns_total": 5945,
    "eval_best_exact": 86.78514276088605,
    "eval_best_exact_thresh": 0.0,
    "eval_best_f1": 89.53654936623764,
    "eval_best_f1_thresh": 0.0,
    "eval_exact": 86.78514276088605,
    "eval_f1": 89.53654936623776,
    "eval_runtime": 1908.3189,
    "eval_samples": 12001,
    "eval_samples_per_second": 6.289,
    "eval_steps_per_second": 0.787,
    "eval_total": 11873
}

# Squad
{
    "eval_HasAns_exact": 85.99810785241249,
    "eval_HasAns_f1": 91.296119057944,
    "eval_HasAns_total": 10570,
    "eval_best_exact": 85.99810785241249,
    "eval_best_exact_thresh": 0.0,
    "eval_best_f1": 91.296119057944,
    "eval_best_f1_thresh": 0.0,
    "eval_exact": 85.99810785241249,
    "eval_f1": 91.296119057944,
    "eval_runtime": 1508.9596,
    "eval_samples": 10657,
    "eval_samples_per_second": 7.062,
    "eval_steps_per_second": 0.883,
    "eval_total": 10570
}
```

### Using with Peft
**NOTE**: This requires code in the PR https://github.com/huggingface/peft/pull/473 for the PEFT library.
```python
#!pip install peft

from peft import LoraConfig, PeftModelForQuestionAnswering
from transformers import AutoModelForQuestionAnswering, AutoTokenizer
model_name = "sjrhuschlee/flan-t5-large-squad2"
```