The XLM model was proposed in Cross-lingual Language Model Pretraining by Guillaume Lample, Alexis Conneau. It's a transformer pretrained using one of the following objectives:
- a causal language modeling (CLM) objective (next token prediction),
- a masked language modeling (MLM) objective (BERT-like), or
- a Translation Language Modeling (TLM) object (extension of BERT's MLM to multiple language inputs)
The abstract from the paper is the following:
Recent studies have demonstrated the efficiency of generative pretraining for English natural language understanding. In this work, we extend this approach to multiple languages and show the effectiveness of cross-lingual pretraining. We propose two methods to learn cross-lingual language models (XLMs): one unsupervised that only relies on monolingual data, and one supervised that leverages parallel data with a new cross-lingual language model objective. We obtain state-of-the-art results on cross-lingual classification, unsupervised and supervised machine translation. On XNLI, our approach pushes the state of the art by an absolute gain of 4.9% accuracy. On unsupervised machine translation, we obtain 34.3 BLEU on WMT'16 German-English, improving the previous state of the art by more than 9 BLEU. On supervised machine translation, we obtain a new state of the art of 38.5 BLEU on WMT'16 Romanian-English, outperforming the previous best approach by more than 4 BLEU. Our code and pretrained models will be made publicly available.
Tips:
- XLM has many different checkpoints, which were trained using different objectives: CLM, MLM or TLM. Make sure to select the correct objective for your task (e.g. MLM checkpoints are not suitable for generation).
- XLM has multilingual checkpoints which leverage a specific :obj:`lang` parameter. Check out the :doc:`multi-lingual <../multilingual>` page for more information.
The original code can be found here.
.. autoclass:: transformers.XLMConfig :members:
.. autoclass:: transformers.XLMTokenizer :members: build_inputs_with_special_tokens, get_special_tokens_mask, create_token_type_ids_from_sequences, save_vocabulary
.. autoclass:: transformers.modeling_xlm.XLMForQuestionAnsweringOutput :members:
.. autoclass:: transformers.XLMModel :members: forward
.. autoclass:: transformers.XLMWithLMHeadModel :members: forward
.. autoclass:: transformers.XLMForSequenceClassification :members: forward
.. autoclass:: transformers.XLMForMultipleChoice :members: forward
.. autoclass:: transformers.XLMForTokenClassification :members: forward
.. autoclass:: transformers.XLMForQuestionAnsweringSimple :members: forward
.. autoclass:: transformers.XLMForQuestionAnswering :members: forward
.. autoclass:: transformers.TFXLMModel :members: call
.. autoclass:: transformers.TFXLMWithLMHeadModel :members: call
.. autoclass:: transformers.TFXLMForSequenceClassification :members: call
.. autoclass:: transformers.TFXLMForMultipleChoice :members: call
.. autoclass:: transformers.TFXLMForTokenClassification :members: call
.. autoclass:: transformers.TFXLMForQuestionAnsweringSimple :members: call