dl-translate 0.2.2

A deep learning-based translation library built on Huggingface transformers

DL Translate

A deep learning-based translation library built on Huggingface transformers and Facebook's mBART-Large

💻 GitHub Repository
📚 Documentation / Readthedocs
🐍 PyPi project
🧪 Colab Demo / Kaggle Demo

Quickstart

Install the library with pip:

pip install dl-translate

To translate some text:

import dl_translate as dlt

mt = dlt.TranslationModel()  # Slow when you load it for the first time

text_hi = "संयुक्त राष्ट्र के प्रमुख का कहना है कि सीरिया में कोई सैन्य समाधान नहीं है"
mt.translate(text_hi, source=dlt.lang.HINDI, target=dlt.lang.ENGLISH)

Above, you can see that dlt.lang contains variables representing each of the 50 available languages with auto-complete support. Alternatively, you can specify the language (e.g. "Arabic") or the language code (e.g. "fr" for French):

text_ar = "الأمين العام للأمم المتحدة يقول إنه لا يوجد حل عسكري في سوريا."
mt.translate(text_ar, source="Arabic", target="fr")

If you want to verify whether a language is available, you can check it:

print(mt.available_languages())  # All languages that you can use
print(mt.available_codes())  # Code corresponding to each language accepted
print(mt.get_lang_code_map())  # Dictionary of lang -> code

Usage

Selecting a device

When you load the model, you can specify the device:

mt = dlt.TranslationModel(device="auto")

By default, the value will be device="auto", which means it will use a GPU if possible. You can also explicitly set device="cpu" or device="gpu", or some other strings accepted by torch.device(). In general, it is recommend to use a GPU if you want a reasonable processing time.

Choosing a different model

Two model families are available at the moment: m2m100 and mBART-50 Large, which respective allow translation across over 100 languages and 50 languages. By default, the model will select m2m100, but you can also explicitly choose the model by specifying the shorthand ("m2m100" or "mbart50") or the full repository name (e.g. "facebook/m2m100_418M"). For example:

# The following ways are equivalent
mt = dlt.TranslationModel("m2m100")  # Default
mt = dlt.TranslationModel("facebook/m2m100_418M")

# The following ways are equivalent
mt = dlt.TranslationModel("mbart50")
mt = dlt.TranslationModel("facebook/mbart-large-50-many-to-many-mmt")

Note that the language code will change depending on the model family. To find out the correct language codes, please read the doc page on available languages or run mt.available_codes().

By default, dlt.TranslationModel will download the model from the huggingface repo for mbart50 or m2m100 and cache it. It's possible to load the model from a path or a model with a similar format, but you will need to specify the model_family:

mt = dlt.TranslationModel("/path/to/model/directory/", model_family="mbart50")
mt = dlt.TranslationModel("facebook/m2m100_1.2B", model_family="m2m100")

Notes:

• Make sure your tokenizer is also stored in the same directory if you load from a file.
• The available languages will change if you select a different model, so you will not be able to leverage dlt.lang or dlt.utils.

Splitting into sentences

It is not recommended to use extremely long texts as it takes more time to process. Instead, you can try to break them down into sentences with the help of nltk. First install the library with pip install nltk, then run:

import nltk

nltk.download("punkt")

text = "Mr. Smith went to his favorite cafe. There, he met his friend Dr. Doe."
sents = nltk.tokenize.sent_tokenize(text, "english")  # don't use dlt.lang.ENGLISH
" ".join(mt.translate(sents, source=dlt.lang.ENGLISH, target=dlt.lang.FRENCH))

Batch size during translation

It's possible to set a batch size (i.e. the number of elements processed at once) for mt.translate and whether you want to see the progress bar or not:

# ...
mt = dlt.TranslationModel()
mt.translate(text, source, target, batch_size=32, verbose=True)

If you set batch_size=None, it will compute the entire text at once rather than splitting into "chunks". We recommend lowering batch_size if you do not have a lot of RAM or VRAM and run into CUDA memory error. Set a higher value if you are using a high-end GPU and the VRAM is not fully utilized.

dlt.utils module

An alternative to mt.available_languages() is the dlt.utils module. You can use it to find out which languages and codes are available:

print(dlt.utils.available_languages('mbart50'))  # All languages that you can use
print(dlt.utils.available_codes('mbart50'))  # Code corresponding to each language accepted
print(dlt.utils.get_lang_code_map('mbart50'))  # Dictionary of lang -> code

Advanced

If you have knowledge of PyTorch and Huggingface Transformers, you can access advanced aspects of the library for more customization:

• Saving and loading: If you wish to accelerate the loading time the translation model, you can use save_obj and reload it later with load_obj. This method is only recommended if you are familiar with huggingface and torch; please read the docs for more information.
• Interacting with underlying model and tokenizer: When initializing model, you can pass in arguments for the underlying BART model and tokenizer with model_options and tokenizer_options respectively. You can also access the underlying transformers with mt.get_transformers_model().
• Keyword arguments for the generate() method: When running mt.translate, you can also give generation_options that is passed to the generate() method of the underlying transformer model.

For more information, please visit the advanced section of the user guide (also available in the readthedocs version).

Acknowledgement

dl-translate is built on top of Huggingface's implementation of two models created by Facebook AI Research.

1. The multilingual BART finetuned on many-to-many translation of over 50 languages, which is documented here The original paper was written by Tang et. al from Facebook AI Research; you can find it here and cite it using the following:

   @article{tang2020multilingual,
       title={Multilingual translation with extensible multilingual pretraining and finetuning},
       author={Tang, Yuqing and Tran, Chau and Li, Xian and Chen, Peng-Jen and Goyal, Naman and Chaudhary, Vishrav and Gu, Jiatao and Fan, Angela},
       journal={arXiv preprint arXiv:2008.00401},
       year={2020}
   }
   

2. The transformer model published in Beyond English-Centric Multilingual Machine Translation by Fan et. al, which supports over 100 languages. You can cite it here:

   @misc{fan2020englishcentric,
        title={Beyond English-Centric Multilingual Machine Translation}, 
        author={Angela Fan and Shruti Bhosale and Holger Schwenk and Zhiyi Ma and Ahmed El-Kishky and Siddharth Goyal and Mandeep Baines and Onur Celebi and Guillaume Wenzek and Vishrav Chaudhary and Naman Goyal and Tom Birch and Vitaliy Liptchinsky and Sergey Edunov and Edouard Grave and Michael Auli and Armand Joulin},
        year={2020},
        eprint={2010.11125},
        archivePrefix={arXiv},
        primaryClass={cs.CL}
    }
   

dlt is a wrapper with useful utils to save you time. For huggingface's transformers, the following snippet is shown as an example:

from transformers import MBartForConditionalGeneration, MBart50TokenizerFast

article_hi = "संयुक्त राष्ट्र के प्रमुख का कहना है कि सीरिया में कोई सैन्य समाधान नहीं है"
article_ar = "الأمين العام للأمم المتحدة يقول إنه لا يوجد حل عسكري في سوريا."

model = MBartForConditionalGeneration.from_pretrained("facebook/mbart-large-50-many-to-many-mmt")
tokenizer = MBart50TokenizerFast.from_pretrained("facebook/mbart-large-50-many-to-many-mmt")

# translate Hindi to French
tokenizer.src_lang = "hi_IN"
encoded_hi = tokenizer(article_hi, return_tensors="pt")
generated_tokens = model.generate(**encoded_hi, forced_bos_token_id=tokenizer.lang_code_to_id["fr_XX"])
tokenizer.batch_decode(generated_tokens, skip_special_tokens=True)
# => "Le chef de l 'ONU affirme qu 'il n 'y a pas de solution militaire en Syria."

# translate Arabic to English
tokenizer.src_lang = "ar_AR"
encoded_ar = tokenizer(article_ar, return_tensors="pt")
generated_tokens = model.generate(**encoded_ar, forced_bos_token_id=tokenizer.lang_code_to_id["en_XX"])
tokenizer.batch_decode(generated_tokens, skip_special_tokens=True)
# => "The Secretary-General of the United Nations says there is no military solution in Syria."

With dlt, you can run:

import dl_translate as dlt

article_hi = "संयुक्त राष्ट्र के प्रमुख का कहना है कि सीरिया में कोई सैन्य समाधान नहीं है"
article_ar = "الأمين العام للأمم المتحدة يقول إنه لا يوجد حل عسكري في سوريا."

mt = dlt.TranslationModel()
translated_fr = mt.translate(article_hi, source=dlt.lang.HINDI, target=dlt.lang.FRENCH)
translated_en = mt.translate(article_ar, source=dlt.lang.ARABIC, target=dlt.lang.ENGLISH)

Notice you don't have to think about tokenizers, condition generation, pretrained models, and regional codes; you can just tell the model what to translate!

If you are experienced with huggingface's ecosystem, then you should be familiar enough with the example above that you wouldn't need this library. However, if you've never heard of huggingface or mBART, then I hope using this library will give you enough motivation to learn more about them :)