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*This model was released on 2020-04-06 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">
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# MobileBERT

[MobileBERT](https://huggingface.co/papers/2004.02984) is a lightweight and efficient variant of BERT, specifically designed for resource-limited devices such as mobile phones. It retains BERT's architecture but significantly reduces model size and inference latency while maintaining strong performance on NLP tasks. MobileBERT achieves this through a bottleneck structure and carefully balanced self-attention and feedforward networks. The model is trained by knowledge transfer from a large BERT model with an inverted bottleneck structure.

You can find the original MobileBERT checkpoint under the [Google](https://huggingface.co/google/mobilebert-uncased) organization.
> [!TIP]
> Click on the MobileBERT models in the right sidebar for more examples of how to apply MobileBERT 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="google/mobilebert-uncased",
    dtype=torch.float16,
    device=0
)
pipeline("The capital of France is [MASK].")
```

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

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

tokenizer = AutoTokenizer.from_pretrained(
    "google/mobilebert-uncased",
)
model = AutoModelForMaskedLM.from_pretrained(
    "google/mobilebert-uncased",
    dtype=torch.float16,
    device_map="auto",
)
inputs = tokenizer("The capital of France is [MASK].", 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 "The capital of France is [MASK]." | transformers run --task fill-mask --model google/mobilebert-uncased --device 0
```

</hfoption>
</hfoptions>

## Notes

- Inputs should be padded on the right because BERT uses absolute position embeddings.

## MobileBertConfig

[[autodoc]] MobileBertConfig

## MobileBertTokenizer

[[autodoc]] MobileBertTokenizer

## MobileBertTokenizerFast

[[autodoc]] MobileBertTokenizerFast

## MobileBert specific outputs

[[autodoc]] models.mobilebert.modeling_mobilebert.MobileBertForPreTrainingOutput

## MobileBertModel

[[autodoc]] MobileBertModel
    - forward

## MobileBertForPreTraining

[[autodoc]] MobileBertForPreTraining
    - forward

## MobileBertForMaskedLM

[[autodoc]] MobileBertForMaskedLM
    - forward

## MobileBertForNextSentencePrediction

[[autodoc]] MobileBertForNextSentencePrediction
    - forward

## MobileBertForSequenceClassification

[[autodoc]] MobileBertForSequenceClassification
    - forward

## MobileBertForMultipleChoice

[[autodoc]] MobileBertForMultipleChoice
    - forward

## MobileBertForTokenClassification

[[autodoc]] MobileBertForTokenClassification
    - forward

## MobileBertForQuestionAnswering

[[autodoc]] MobileBertForQuestionAnswering
    - forward
