README.md

---
license: cc-by-sa-4.0
language:
- ja
library_name: transformers
---

# Model Card for Japanese BART V2 base

## Model description

This is a Japanese BART V2 base model pre-trained on Japanese Wikipedia.

## How to use

You can use this model as follows:

```python
from transformers import XLMRobertaTokenizer, MBartForConditionalGeneration
tokenizer = XLMRobertaTokenizer.from_pretrained('ku-nlp/bart-v2-base-japanese')
model = MBartForConditionalGeneration.from_pretrained('ku-nlp/bart-v2-base-japanese/')
sentence = '京都 大学 で 自然 言語 処理 を 専攻 する 。'  # input should be segmented into words by Juman++ in advance
encoding = tokenizer(sentence, return_tensors='pt')
...
```

You can fine-tune this model on downstream tasks.

## Tokenization

The input text should be segmented into words by [Juman++](https://github.com/ku-nlp/jumanpp) in advance. [Juman++ 2.0.0-rc3](https://github.com/ku-nlp/jumanpp/releases/tag/v2.0.0-rc3) was used for pre-training. Each word is tokenized into subwords by [sentencepiece](https://github.com/google/sentencepiece).

## Training data

We used the following corpora for pre-training:

- Japanese Wikipedia (18M sentences)

## Training procedure

We first segmented texts in the corpora into words using [Juman++](https://github.com/ku-nlp/jumanpp).
Then, we built a sentencepiece model with 32000 tokens including words ([JumanDIC](https://github.com/ku-nlp/JumanDIC)) and subwords induced by the unigram language model of [sentencepiece](https://github.com/google/sentencepiece).

We tokenized the segmented corpora into subwords using the sentencepiece model and trained the Japanese BART model using [transformers](https://github.com/huggingface/transformers) library.
The training took 2 weeks using 4 Tesla V100 GPUs.

The following hyperparameters were used during pre-training:

- distributed_type: multi-GPU
- num_devices: 4
- batch_size: 512
- training_steps: 500,000
- encoder-decoder layers: 6
- hidden: 768