build_generator api changes for the scripted SequenceGenerator (#697)

Summary:
Pull Request resolved: pytorch/translate#697

Pull Request resolved: #1922

Pull Request resolved: fairinternal/fairseq-py#1117

We are planning to deprecate the original SequenceGenerator and use the ScriptSequenceGenerator in the Fairseq. Due to the change of scripted Sequence Generator constructor, I change `build_generator` interface in Fairseq, pyspeech and pytorch translate.

Reviewed By: myleott

Differential Revision: D20683836

fbshipit-source-id: d01d891ebd067fe44291d3a0a784935edaf66acd

Author: liuchen9494

examples/speech_recognition/infer.py

@@ -208,7 +208,7 @@ def main(args):
 
     # Initialize generator
     gen_timer = meters.StopwatchMeter()
-    generator = task.build_generator(args)
+    generator = task.build_generator(models, args)
 
     num_sentences = 0
 

examples/speech_recognition/tasks/speech_recognition.py

@@ -108,7 +108,7 @@ def load_dataset(self, split, combine=False, **kwargs):
         data_json_path = os.path.join(self.args.data, "{}.json".format(split))
         self.datasets[split] = get_asr_dataset_from_json(data_json_path, self.tgt_dict)
 
-    def build_generator(self, args):
+    def build_generator(self, models, args):
         w2l_decoder = getattr(args, "w2l_decoder", None)
         if w2l_decoder == "viterbi":
             from examples.speech_recognition.w2l_decoder import W2lViterbiDecoder
@@ -119,7 +119,7 @@ def build_generator(self, args):
 
             return W2lKenLMDecoder(args, self.target_dictionary)
         else:
-            return super().build_generator(args)
+            return super().build_generator(models, args)
 
     @property
     def target_dictionary(self):

fairseq/hub_utils.py

@@ -157,7 +157,7 @@ def generate(
         gen_args.beam = beam
         for k, v in kwargs.items():
             setattr(gen_args, k, v)
-        generator = self.task.build_generator(gen_args)
+        generator = self.task.build_generator(self.models, gen_args)
 
         results = []
         for batch in self._build_batches(tokenized_sentences, skip_invalid_size_inputs):

fairseq/models/bart/hub_interface.py

@@ -115,7 +115,7 @@ def generate(self, tokens: List[torch.LongTensor], beam: int = 5, verbose: bool
         gen_args.beam = beam
         for k, v in kwargs.items():
             setattr(gen_args, k, v)
-        generator = self.task.build_generator(gen_args)
+        generator = self.task.build_generator([self.model], gen_args)
         translations = self.task.inference_step(
             generator,
             [self.model],

fairseq/tasks/fairseq_task.py

@@ -225,7 +225,7 @@ def build_criterion(self, args):
 
         return criterions.build_criterion(args, self)
 
-    def build_generator(self, args):
+    def build_generator(self, models, args):
         if getattr(args, "score_reference", False):
             from fairseq.sequence_scorer import SequenceScorer
 

fairseq/tasks/translation.py

@@ -261,6 +261,7 @@ def build_dataset_for_inference(self, src_tokens, src_lengths):
         return LanguagePairDataset(src_tokens, src_lengths, self.source_dictionary)
 
     def build_model(self, args):
+        model = super().build_model(args)
         if getattr(args, 'eval_bleu', False):
             assert getattr(args, 'eval_bleu_detok', None) is not None, (
                 '--eval-bleu-detok is required if using --eval-bleu; '
@@ -274,8 +275,8 @@ def build_model(self, args):
             ))
 
             gen_args = json.loads(getattr(args, 'eval_bleu_args', '{}') or '{}')
-            self.sequence_generator = self.build_generator(Namespace(**gen_args))
-        return super().build_model(args)
+            self.sequence_generator = self.build_generator([model], Namespace(**gen_args))
+        return model
 
     def valid_step(self, sample, model, criterion):
         loss, sample_size, logging_output = super().valid_step(sample, model, criterion)

fairseq/tasks/translation_from_pretrained_bart.py

@@ -79,7 +79,7 @@ def load_dataset(self, split, epoch=1, combine=False, **kwargs):
             append_source_id=True
             )
 
-    def build_generator(self, args):
+    def build_generator(self, models, args):
         if getattr(args, 'score_reference', False):
             from fairseq.sequence_scorer import SequenceScorer
             return SequenceScorer(

fairseq/tasks/translation_lev.py

@@ -126,7 +126,8 @@ def _full_mask(target_tokens):
         else:
             raise NotImplementedError
 
-    def build_generator(self, args):
+    def build_generator(self, models, args):
+        # add models input to match the API for SequenceGenerator
         from fairseq.iterative_refinement_generator import IterativeRefinementGenerator
         return IterativeRefinementGenerator(
             self.target_dictionary,

fairseq_cli/generate.py

@@ -111,7 +111,7 @@ def _main(args, output_file):
 
     # Initialize generator
     gen_timer = StopwatchMeter()
-    generator = task.build_generator(args)
+    generator = task.build_generator(models, args)
 
     # Handle tokenization and BPE
     tokenizer = encoders.build_tokenizer(args)

fairseq_cli/interactive.py

@@ -112,7 +112,7 @@ def main(args):
             model.cuda()
 
     # Initialize generator
-    generator = task.build_generator(args)
+    generator = task.build_generator(models, args)
 
     # Handle tokenization and BPE
     tokenizer = encoders.build_tokenizer(args)