roberta.md

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*This model was released on 2019-07-26 and added to Hugging Face Transformers on 2020-11-16.*

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        <img alt="PyTorch" src="https://img.shields.io/badge/PyTorch-DE3412?style=flat&logo=pytorch&logoColor=white">
        <img alt="SDPA" src="https://img.shields.io/badge/SDPA-DE3412?style=flat&logo=pytorch&logoColor=white">
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</div>

# RoBERTa

[RoBERTa](https://huggingface.co/papers/1907.11692) improves BERT with new pretraining objectives, demonstrating [BERT](./bert) was undertrained and training design is important. The pretraining objectives include dynamic masking, sentence packing, larger batches and a byte-level BPE tokenizer.

You can find all the original RoBERTa checkpoints under the [Facebook AI](https://huggingface.co/FacebookAI) organization.

> [!TIP]
> Click on the RoBERTa models in the right sidebar for more examples of how to apply RoBERTa to different language tasks.

The example below demonstrates how to predict the `<mask>` token with [`Pipeline`], [`AutoModel`], and from the command line.

<hfoptions id="usage">
<hfoption id="Pipeline">

```py
import torch
from transformers import pipeline

pipeline = pipeline(
    task="fill-mask",
    model="FacebookAI/roberta-base",
    dtype=torch.float16,
    device=0
)
pipeline("Plants create <mask> through a process known as photosynthesis.")
```

</hfoption>
<hfoption id="AutoModel">

```py
import torch
from transformers import AutoModelForMaskedLM, AutoTokenizer

tokenizer = AutoTokenizer.from_pretrained(
    "FacebookAI/roberta-base",
)
model = AutoModelForMaskedLM.from_pretrained(
    "FacebookAI/roberta-base",
    dtype=torch.float16,
    device_map="auto",
    attn_implementation="sdpa"
)
inputs = tokenizer("Plants create <mask> through a process known as photosynthesis.", return_tensors="pt").to(model.device)

with torch.no_grad():
    outputs = model(**inputs)
    predictions = outputs.logits

masked_index = torch.where(inputs['input_ids'] == tokenizer.mask_token_id)[1]
predicted_token_id = predictions[0, masked_index].argmax(dim=-1)
predicted_token = tokenizer.decode(predicted_token_id)

print(f"The predicted token is: {predicted_token}")
```

</hfoption>
<hfoption id="transformers CLI">

```bash
echo -e "Plants create <mask> through a process known as photosynthesis." | transformers run --task fill-mask --model FacebookAI/roberta-base --device 0
```

</hfoption>
</hfoptions>

## Notes

- RoBERTa doesn't have `token_type_ids` so you don't need to indicate which token belongs to which segment. Separate your segments with the separation token `tokenizer.sep_token` or `</s>`.

## RobertaConfig

[[autodoc]] RobertaConfig

## RobertaTokenizer

[[autodoc]] RobertaTokenizer
    - build_inputs_with_special_tokens
    - get_special_tokens_mask
    - create_token_type_ids_from_sequences
    - save_vocabulary

## RobertaTokenizerFast

[[autodoc]] RobertaTokenizerFast
    - build_inputs_with_special_tokens

## RobertaModel

[[autodoc]] RobertaModel
    - forward

## RobertaForCausalLM

[[autodoc]] RobertaForCausalLM
    - forward

## RobertaForMaskedLM

[[autodoc]] RobertaForMaskedLM
    - forward

## RobertaForSequenceClassification

[[autodoc]] RobertaForSequenceClassification
    - forward

## RobertaForMultipleChoice

[[autodoc]] RobertaForMultipleChoice
    - forward

## RobertaForTokenClassification

[[autodoc]] RobertaForTokenClassification
    - forward

## RobertaForQuestionAnswering

[[autodoc]] RobertaForQuestionAnswering
    - forward