Backward reranking public (#667)

Summary:
Implementation of noisy channel model reranking for release with paper
Pull Request resolved: fairinternal/fairseq-py#667

Reviewed By: michaelauli

Differential Revision: D15901665

Pulled By: nng555

fbshipit-source-id: 2de2c518be8e5828ffad72db3e741b0940623373

Author: nng555

.gitignore

@@ -116,3 +116,6 @@ fairseq/modules/*_layer/*_backward.cu
 
 # data
 data-bin/
+
+# reranking
+examples/reranking/rerank_data

eval_lm.py

@@ -146,8 +146,9 @@ def main(parsed_args):
             hypos = scorer.generate(models, sample)
             gen_timer.stop(sample['ntokens'])
 
-            for hypos_i in hypos:
+            for i, hypos_i in enumerate(hypos):
                 hypo = hypos_i[0]
+                sample_id = sample['id'][i]
 
                 tokens = hypo['tokens']
                 tgt_len = tokens.numel()
@@ -199,7 +200,8 @@ def main(parsed_args):
                             is_bpe = False
                             w = ''
                     if args.output_word_probs:
-                        print('\t'.join('{} [{:2f}]'.format(x[0], x[1]) for x in word_prob))
+                        print(str(int(sample_id)) + " " +
+                                  ('\t'.join('{} [{:2f}]'.format(x[0], x[1]) for x in word_prob)))
 
             wps_meter.update(sample['ntokens'])
             t.log({'wps': round(wps_meter.avg)})

examples/__init__.py

@@ -0,0 +1,10 @@
+# Copyright (c) 2017-present, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the license found in the LICENSE file in
+# the root directory of this source tree. An additional grant of patent rights
+# can be found in the PATENTS file in the same directory.
+
+__version__ = '0.7.2'
+
+import examples.noisychannel # noqa

examples/noisychannel/README.md

@@ -0,0 +1,72 @@
+# Simple and Effective Noisy Channel Modeling for Neural Machine Translation (Yee et al., 2019)
+This page contains pointers to pre-trained models as well as instructions on how to run the reranking scripts.
+
+## Citation:
+```bibtex
+@inproceedings{yee2018simple,
+  title = {Simple and Effective Noisy Channel Modeling for Neural Machine Translation},
+  author = {Kyra Yee and Yann Dauphin and Michael Auli},
+  booktitle = {Conference on Empirical Methods in Natural Language Processing},
+  year = {2019},
+}
+```
+
+## Pre-trained Models:
+
+Model | Description |  Download
+---|---|---
+`transformer.noisychannel.de-en` | De->En Forward Model | [download (.tar.gz)](https://dl.fbaipublicfiles.com/fairseq/models/noisychannel/forward_de2en.tar.bz2)
+`transformer.noisychannel.en-de` | En->De Channel Model | [download (.tar.gz)](https://dl.fbaipublicfiles.com/fairseq/models/noisychannel/backward_en2de.tar.bz2)
+`transformer_lm.noisychannel.en` | En Language model | [download (.tar.gz)](https://dl.fbaipublicfiles.com/fairseq/models/noisychannel/reranking_en_lm.tar.bz2)
+
+Test Data: [newstest_wmt17](https://dl.fbaipublicfiles.com/fairseq/models/noisychannel/wmt17test.tar.bz2)
+
+## Example usage
+
+```
+mkdir rerank_example
+curl https://dl.fbaipublicfiles.com/fairseq/models/noisychannel/forward_de2en.tar.bz2 | tar xvjf - -C rerank_example
+curl https://dl.fbaipublicfiles.com/fairseq/models/noisychannel/backward_en2de.tar.bz2 | tar xvjf - -C rerank_example
+curl https://dl.fbaipublicfiles.com/fairseq/models/noisychannel/reranking_en_lm.tar.bz2 | tar xvjf - -C rerank_example
+curl https://dl.fbaipublicfiles.com/fairseq/models/noisychannel/wmt17test.tar.bz2 | tar xvjf - -C rerank_example
+
+beam=50
+num_trials=1000
+fw_name=fw_model_ex
+bw_name=bw_model_ex
+lm_name=lm_ex
+data_dir=rerank_example/hyphen-splitting-mixed-case-wmt17test-wmt14bpe
+data_dir_name=wmt17
+lm=rerank_example/lm/checkpoint_best.pt
+lm_bpe_code=rerank_example/lm/bpe32k.code
+lm_dict=rerank_example/lm/dict.txt
+batch_size=32
+bw=rerank_example/backward_en2de.pt
+fw=rerank_example/forward_de2en.pt
+
+# reranking with P(T|S) P(S|T) and P(T)
+python examples/noisychannel/rerank_tune.py $data_dir  --tune-param lenpen weight1 weight3  \
+    --lower-bound 0 0 0 --upper-bound 3 3 3 --data-dir-name $data_dir_name  \ 
+    --num-trials $num_trials  --source-lang de --target-lang en --gen-model $fw \
+    -n $beam --batch-size $batch_size --score-model2 $fw --score-model1 $bw \
+    --backwards1 --weight2 1 \
+    -lm $lm  --lm-dict $lm_dict  --lm-name en_newscrawl --lm-bpe-code $lm_bpe_code \
+    --model2-name $fw_name --model1-name $bw_name --gen-model-name $fw_name
+
+# reranking with P(T|S) and P(T)
+python examples/noisychannel/rerank_tune.py $data_dir  --tune-param lenpen weight3 \
+    --lower-bound 0 0 --upper-bound 3 3  --data-dir-name $data_dir_name  \
+    --num-trials $num_trials  --source-lang de --target-lang en --gen-model $fw \
+    -n $beam --batch-size $batch_size --score-model1 $fw \
+    -lm $lm  --lm-dict $lm_dict  --lm-name en_newscrawl --lm-bpe-code $lm_bpe_code \
+    --model1-name $fw_name --gen-model-name $fw_name
+
+# to run with a preconfigured set of hyperparameters for the lenpen and model weights, using rerank.py instead.
+python examples/noisychannel/rerank.py $data_dir \
+    --lenpen 0.269 --weight1 1 --weight2 0.929 --weight3 0.831  \
+    --data-dir-name $data_dir_name  --source-lang de --target-lang en --gen-model $fw \
+    -n $beam --batch-size $batch_size --score-model2 $fw --score-model1 $bw --backwards1  \
+    -lm $lm  --lm-dict $lm_dict  --lm-name en_newscrawl --lm-bpe-code $lm_bpe_code \
+    --model2-name $fw_name --model1-name $bw_name --gen-model-name $fw_name
+```
+

examples/noisychannel/__init__.py

@@ -0,0 +1,8 @@
+# Copyright (c) 2017-present, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the license found in the LICENSE file in
+# the root directory of this source tree. An additional grant of patent rights
+# can be found in the PATENTS file in the same directory.
+
+from .rerank_options import *