Fix building of docs

docs/conf.py

@@ -50,7 +50,7 @@
 
 # General information about the project.
 project = 'fairseq'
-copyright = '2018, Facebook AI Research (FAIR)'
+copyright = '2019, Facebook AI Research (FAIR)'
 author = 'Facebook AI Research (FAIR)'
 
 github_doc_root = 'https://github.com/pytorch/fairseq/tree/master/docs/'

examples/backtranslation/README.md

@@ -8,9 +8,14 @@ Model | Description | Dataset | Download
 ---|---|---|---
 `transformer.wmt18.en-de` | Transformer <br> ([Edunov et al., 2018](https://arxiv.org/abs/1808.09381)) <br> WMT'18 winner | [WMT'18 English-German](http://www.statmt.org/wmt18/translation-task.html) | [download (.tar.gz)](https://dl.fbaipublicfiles.com/fairseq/models/wmt18.en-de.ensemble.tar.gz) <br> See NOTE in the archive
 
-## Example usage
+## Example usage (torch.hub)
 
-Interactive generation from the full ensemble via PyTorch Hub:
+We require a few additional Python dependencies for preprocessing:
+```bash
+pip install subword_nmt sacremoses
+```
+
+Then to generate translations from the full model ensemble:
 ```python
 import torch
 

examples/language_model/README.md

@@ -12,6 +12,11 @@ Model | Description | Dataset | Download
 
 ## Example usage
 
+We require a few additional Python dependencies for preprocessing:
+```bash
+pip install fastBPE sacremoses
+```
+
 To sample from a language model using PyTorch Hub:
 ```python
 import torch

examples/translation/README.md

@@ -20,6 +20,11 @@ Model | Description | Dataset | Download
 
 ## Example usage (torch.hub)
 
+We require a few additional Python dependencies for preprocessing:
+```bash
+pip install sacremoses subword_nmt
+```
+
 Interactive translation via PyTorch Hub:
 ```python
 import torch

examples/wmt19/README.md

@@ -16,6 +16,15 @@ Model | Description | Download
 
 ## Example usage (torch.hub)
 
+#### Requirements
+
+We require a few additional Python dependencies for preprocessing:
+```bash
+pip install fastBPE sacremoses
+```
+
+#### Translation
+
 ```python
 import torch
 
@@ -38,7 +47,11 @@ en2ru.translate("Machine learning is great!")  # 'Машинное обучен
 ru2en = torch.hub.load('pytorch/fairseq', 'transformer.wmt19.ru-en', checkpoint_file='model1.pt:model2.pt:model3.pt:model4.pt',
                        tokenizer='moses', bpe='fastbpe')
 ru2en.translate("Машинное обучение - это здорово!")  # 'Machine learning is great!'
+```
+
+#### Language Modeling
 
+```python
 # Sample from the English LM
 en_lm = torch.hub.load('pytorch.fairseq', 'transformer_lm.wmt19.en', tokenizer='moses', bpe='fastbpe')
 en_lm.sample("Machine learning is")  # 'Machine learning is the future of computing, says Microsoft boss Satya Nadella ...'

setup.py

@@ -4,13 +4,13 @@
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
 
+import os
 from setuptools import setup, find_packages, Extension
-from torch.utils import cpp_extension
 import sys
 
 
-if sys.version_info < (3,):
-    sys.exit('Sorry, Python3 is required for fairseq.')
+if sys.version_info < (3, 5):
+    sys.exit('Sorry, Python >=3.5 is required for fairseq.')
 
 
 with open('README.md') as f:
@@ -61,15 +61,42 @@ def include_dirs(self, dirs):
         language='c++',
         extra_compile_args=extra_compile_args,
     ),
-    cpp_extension.CppExtension(
-        'fairseq.libnat',
-        sources=[
-            'fairseq/clib/libnat/edit_dist.cpp',
-        ],
-    )
 ]
 
 
+cmdclass = {}
+
+
+try:
+    # torch is not available when generating docs
+    from torch.utils import cpp_extension
+    extensions.extend([
+        cpp_extension.CppExtension(
+            'fairseq.libnat',
+            sources=[
+                'fairseq/clib/libnat/edit_dist.cpp',
+            ],
+        ),
+    ])
+    cmdclass['build_ext'] = cpp_extension.BuildExtension
+except ImportError:
+    pass
+
+
+if 'READTHEDOCS' in os.environ:
+    # don't build extensions when generating docs
+    extensions = []
+    if 'build_ext' in cmdclass:
+        del cmdclass['build_ext']
+
+    # use CPU build of PyTorch
+    dependency_links = [
+        'https://download.pytorch.org/whl/cpu/torch-1.3.0%2Bcpu-cp36-cp36m-linux_x86_64.whl'
+    ]
+else:
+    dependency_links = []
+
+
 setup(
     name='fairseq',
     version='0.8.0',
@@ -92,13 +119,13 @@ def include_dirs(self, dirs):
     install_requires=[
         'cffi',
         'cython',
-        'fastBPE',
         'numpy',
         'regex',
         'sacrebleu',
         'torch',
         'tqdm',
     ],
+    dependency_links=dependency_links,
     packages=find_packages(exclude=['scripts', 'tests']),
     ext_modules=extensions,
     test_suite='tests',
@@ -113,6 +140,6 @@ def include_dirs(self, dirs):
             'fairseq-validate = fairseq_cli.validate:cli_main',
         ],
     },
-    cmdclass={'build_ext': cpp_extension.BuildExtension},
+    cmdclass=cmdclass,
     zip_safe=False,
 )