Fairseq(-py) is a sequence modeling toolkit that allows researchers and developers to train custom models for translation, summarization, language modeling and other text generation tasks. We provide reference implementations of various sequence modeling papers:

• May 2020: Follow fairseq on Twitter
• April 2020: Monotonic Multihead Attention code released
• April 2020: Quant-Noise code released
• April 2020: Initial model parallel support and 11B parameters unidirectional LM released
• March 2020: Byte-level BPE code released

• multi-GPU training on one machine or across multiple machines (data and model parallel)
• fast generation on both CPU and GPU with multiple search algorithms implemented:
  • beam search
  • Diverse Beam Search (Vijayakumar et al., 2016)
  • sampling (unconstrained, top-k and top-p/nucleus)
• large mini-batch training even on a single GPU via delayed updates
• mixed precision training (trains faster with less GPU memory on NVIDIA tensor cores)
• extensible: easily register new models, criterions, tasks, optimizers and learning rate schedulers

We also provide pre-trained models for translation and language modeling with a convenient torch.hub interface:

en2de = torch.hub.load('pytorch/fairseq', 'transformer.wmt19.en-de.single_model')
en2de.translate('Hello world', beam=5)
# 'Hallo Welt'

See the PyTorch Hub tutorials for translation and RoBERTa for more examples.

• PyTorch version >= 1.4.0
• Python version >= 3.6
• For training new models, you'll also need an NVIDIA GPU and NCCL
• To install fairseq and develop locally:

git clone https://github.com/pytorch/fairseq
cd fairseq
pip install --editable ./

# on MacOS:
# CFLAGS="-stdlib=libc  " pip install --editable ./

• For faster training install NVIDIA's apex library:

git clone https://github.com/NVIDIA/apex
cd apex
pip install -v --no-cache-dir --global-option="--cpp_ext" --global-option="--cuda_ext" \
  --global-option="--deprecated_fused_adam" --global-option="--xentropy" \
  --global-option="--fast_multihead_attn" ./

• For large datasets install PyArrow: pip install pyarrow
• If you use Docker make sure to increase the shared memory size either with --ipc=host or --shm-size as command line options to nvidia-docker run.

The full documentation contains instructions for getting started, training new models and extending fairseq with new model types and tasks.

We provide pre-trained models and pre-processed, binarized test sets for several tasks listed below, as well as example training and evaluation commands.

• Translation: convolutional and transformer models are available
• Language Modeling: convolutional and transformer models are available

We also have more detailed READMEs to reproduce results from specific papers:

• Training with Quantization Noise for Extreme Model Compression
• Neural Machine Translation with Byte-Level Subwords (Wang et al., 2020)
• Multilingual Denoising Pre-training for Neural Machine Translation (Liu et at., 2020)
• Jointly Learning to Align and Translate with Transformer Models (Garg et al., 2019)
• Levenshtein Transformer (Gu et al., 2019)
• Facebook FAIR's WMT19 News Translation Task Submission (Ng et al., 2019)
• RoBERTa: A Robustly Optimized BERT Pretraining Approach (Liu et al., 2019)
• wav2vec: Unsupervised Pre-training for Speech Recognition (Schneider et al., 2019)
• Mixture Models for Diverse Machine Translation: Tricks of the Trade (Shen et al., 2019)
• Pay Less Attention with Lightweight and Dynamic Convolutions (Wu et al., 2019)
• Understanding Back-Translation at Scale (Edunov et al., 2018)
• Classical Structured Prediction Losses for Sequence to Sequence Learning (Edunov et al., 2018)
• Hierarchical Neural Story Generation (Fan et al., 2018)
• Scaling Neural Machine Translation (Ott et al., 2018)
• Convolutional Sequence to Sequence Learning (Gehring et al., 2017)
• Language Modeling with Gated Convolutional Networks (Dauphin et al., 2017)

• Twitter: https://twitter.com/fairseq
• Facebook page: https://www.facebook.com/groups/fairseq.users
• Google group: https://groups.google.com/forum/#!forum/fairseq-users

fairseq(-py) is MIT-licensed. The license applies to the pre-trained models as well.

Please cite as:

@inproceedings{ott2019fairseq,
  title = {fairseq: A Fast, Extensible Toolkit for Sequence Modeling},
  author = {Myle Ott and Sergey Edunov and Alexei Baevski and Angela Fan and Sam Gross and Nathan Ng and David Grangier and Michael Auli},
  booktitle = {Proceedings of NAACL-HLT 2019: Demonstrations},
  year = {2019},
}