# MarianMT
**Bugs:** If you see something strange, file a [Github Issue](https://github.com/huggingface/transformers/issues/new?assignees=sshleifer&labels=&template=bug-report.md&title)
and assign @patrickvonplaten.
Translations should be similar, but not identical to output in the test set linked to in each model card.
Tips:
- A framework for translation models, using the same models as BART.
## Implementation Notes
- Each model is about 298 MB on disk, there are more than 1,000 models.
- The list of supported language pairs can be found [here](https://huggingface.co/Helsinki-NLP).
- Models were originally trained by [Jörg Tiedemann](https://researchportal.helsinki.fi/en/persons/j%C3%B6rg-tiedemann) using the [Marian](https://marian-nmt.github.io/) C++ library, which supports fast training and translation.
- All models are transformer encoder-decoders with 6 layers in each component. Each model's performance is documented
in a model card.
- The 80 opus models that require BPE preprocessing are not supported.
- The modeling code is the same as [`BartForConditionalGeneration`] with a few minor modifications:
- static (sinusoid) positional embeddings (`MarianConfig.static_position_embeddings=True`)
- no layernorm_embedding (`MarianConfig.normalize_embedding=False`)
- the model starts generating with `pad_token_id` (which has 0 as a token_embedding) as the prefix (Bart uses
``),
- Code to bulk convert models can be found in `convert_marian_to_pytorch.py`.
- This model was contributed by [sshleifer](https://huggingface.co/sshleifer).
## Naming
- All model names use the following format: `Helsinki-NLP/opus-mt-{src}-{tgt}`
- The language codes used to name models are inconsistent. Two digit codes can usually be found [here](https://developers.google.com/admin-sdk/directory/v1/languages), three digit codes require googling "language
code {code}".
- Codes formatted like `es_AR` are usually `code_{region}`. That one is Spanish from Argentina.
- The models were converted in two stages. The first 1000 models use ISO-639-2 codes to identify languages, the second
group use a combination of ISO-639-5 codes and ISO-639-2 codes.
## Examples
- Since Marian models are smaller than many other translation models available in the library, they can be useful for
fine-tuning experiments and integration tests.
- [Fine-tune on GPU](https://github.com/huggingface/transformers/blob/master/examples/legacy/seq2seq/train_distil_marian_enro.sh)
## Multilingual Models
- All model names use the following format: `Helsinki-NLP/opus-mt-{src}-{tgt}`:
- If a model can output multiple languages, and you should specify a language code by prepending the desired output
language to the `src_text`.
- You can see a models's supported language codes in its model card, under target constituents, like in [opus-mt-en-roa](https://huggingface.co/Helsinki-NLP/opus-mt-en-roa).
- Note that if a model is only multilingual on the source side, like `Helsinki-NLP/opus-mt-roa-en`, no language
codes are required.
New multi-lingual models from the [Tatoeba-Challenge repo](https://github.com/Helsinki-NLP/Tatoeba-Challenge)
require 3 character language codes:
```python
>>> from transformers import MarianMTModel, MarianTokenizer
>>> src_text = [
... ">>fra<< this is a sentence in english that we want to translate to french",
... ">>por<< This should go to portuguese",
... ">>esp<< And this to Spanish",
... ]
>>> model_name = "Helsinki-NLP/opus-mt-en-roa"
>>> tokenizer = MarianTokenizer.from_pretrained(model_name)
>>> print(tokenizer.supported_language_codes)
['>>zlm_Latn<<', '>>mfe<<', '>>hat<<', '>>pap<<', '>>ast<<', '>>cat<<', '>>ind<<', '>>glg<<', '>>wln<<', '>>spa<<', '>>fra<<', '>>ron<<', '>>por<<', '>>ita<<', '>>oci<<', '>>arg<<', '>>min<<']
>>> model = MarianMTModel.from_pretrained(model_name)
>>> translated = model.generate(**tokenizer(src_text, return_tensors="pt", padding=True))
>>> [tokenizer.decode(t, skip_special_tokens=True) for t in translated]
["c'est une phrase en anglais que nous voulons traduire en français",
'Isto deve ir para o português.',
'Y esto al español']
```
Here is the code to see all available pretrained models on the hub:
```python
from huggingface_hub import list_models
model_list = list_models()
org = "Helsinki-NLP"
model_ids = [x.modelId for x in model_list if x.modelId.startswith(org)]
suffix = [x.split("/")[1] for x in model_ids]
old_style_multi_models = [f"{org}/{s}" for s in suffix if s != s.lower()]
```
## Old Style Multi-Lingual Models
These are the old style multi-lingual models ported from the OPUS-MT-Train repo: and the members of each language
group:
```python no-style
['Helsinki-NLP/opus-mt-NORTH_EU-NORTH_EU',
'Helsinki-NLP/opus-mt-ROMANCE-en',
'Helsinki-NLP/opus-mt-SCANDINAVIA-SCANDINAVIA',
'Helsinki-NLP/opus-mt-de-ZH',
'Helsinki-NLP/opus-mt-en-CELTIC',
'Helsinki-NLP/opus-mt-en-ROMANCE',
'Helsinki-NLP/opus-mt-es-NORWAY',
'Helsinki-NLP/opus-mt-fi-NORWAY',
'Helsinki-NLP/opus-mt-fi-ZH',
'Helsinki-NLP/opus-mt-fi_nb_no_nn_ru_sv_en-SAMI',
'Helsinki-NLP/opus-mt-sv-NORWAY',
'Helsinki-NLP/opus-mt-sv-ZH']
GROUP_MEMBERS = {
'ZH': ['cmn', 'cn', 'yue', 'ze_zh', 'zh_cn', 'zh_CN', 'zh_HK', 'zh_tw', 'zh_TW', 'zh_yue', 'zhs', 'zht', 'zh'],
'ROMANCE': ['fr', 'fr_BE', 'fr_CA', 'fr_FR', 'wa', 'frp', 'oc', 'ca', 'rm', 'lld', 'fur', 'lij', 'lmo', 'es', 'es_AR', 'es_CL', 'es_CO', 'es_CR', 'es_DO', 'es_EC', 'es_ES', 'es_GT', 'es_HN', 'es_MX', 'es_NI', 'es_PA', 'es_PE', 'es_PR', 'es_SV', 'es_UY', 'es_VE', 'pt', 'pt_br', 'pt_BR', 'pt_PT', 'gl', 'lad', 'an', 'mwl', 'it', 'it_IT', 'co', 'nap', 'scn', 'vec', 'sc', 'ro', 'la'],
'NORTH_EU': ['de', 'nl', 'fy', 'af', 'da', 'fo', 'is', 'no', 'nb', 'nn', 'sv'],
'SCANDINAVIA': ['da', 'fo', 'is', 'no', 'nb', 'nn', 'sv'],
'SAMI': ['se', 'sma', 'smj', 'smn', 'sms'],
'NORWAY': ['nb_NO', 'nb', 'nn_NO', 'nn', 'nog', 'no_nb', 'no'],
'CELTIC': ['ga', 'cy', 'br', 'gd', 'kw', 'gv']
}
```
Example of translating english to many romance languages, using old-style 2 character language codes
```python
>>> from transformers import MarianMTModel, MarianTokenizer
>>> src_text = [
... ">>fr<< this is a sentence in english that we want to translate to french",
... ">>pt<< This should go to portuguese",
... ">>es<< And this to Spanish",
... ]
>>> model_name = "Helsinki-NLP/opus-mt-en-ROMANCE"
>>> tokenizer = MarianTokenizer.from_pretrained(model_name)
>>> model = MarianMTModel.from_pretrained(model_name)
>>> translated = model.generate(**tokenizer(src_text, return_tensors="pt", padding=True))
>>> tgt_text = [tokenizer.decode(t, skip_special_tokens=True) for t in translated]
["c'est une phrase en anglais que nous voulons traduire en français",
'Isto deve ir para o português.',
'Y esto al español']
```
## Documentation resources
- [Translation task guide](./tasks/translation)
- [Summarization task guide](./tasks/summarization)
- [Causal language modeling task guide](./tasks/language_modeling)
## MarianConfig
[[autodoc]] MarianConfig
## MarianTokenizer
[[autodoc]] MarianTokenizer
- build_inputs_with_special_tokens
## MarianModel
[[autodoc]] MarianModel
- forward
## MarianMTModel
[[autodoc]] MarianMTModel
- forward
## MarianForCausalLM
[[autodoc]] MarianForCausalLM
- forward
## TFMarianModel
[[autodoc]] TFMarianModel
- call
## TFMarianMTModel
[[autodoc]] TFMarianMTModel
- call
## FlaxMarianModel
[[autodoc]] FlaxMarianModel
- __call__
## FlaxMarianMTModel
[[autodoc]] FlaxMarianMTModel
- __call__