Remove unused FairseqTask.grad_denom and FairseqCriterion.grad_denom

Summary: Pull Request resolved: fairinternal/fairseq-py#979

Differential Revision: D19347309

Pulled By: myleott

fbshipit-source-id: ee6fc6111994d35e95ca0ef4cd8f5932e621d84b

Author: Myle Ott

fairseq/criterions/fairseq_criterion.py

@@ -37,8 +37,3 @@ def forward(self, model, sample, reduce=True):
     def aggregate_logging_outputs(logging_outputs):
         """Aggregate logging outputs from data parallel training."""
         raise NotImplementedError
-
-    @staticmethod
-    def grad_denom(sample_sizes):
-        """Compute the gradient denominator for a set of sample sizes."""
-        return sum(sample_sizes)

fairseq/tasks/fairseq_task.py

@@ -308,9 +308,6 @@ def update_step(self, num_updates):
            learning rate update of each step"""
         pass
 
-    def grad_denom(self, sample_sizes, criterion):
-        return criterion.__class__.grad_denom(sample_sizes)
-
     def aggregate_logging_outputs(self, logging_outputs, criterion):
         return criterion.__class__.aggregate_logging_outputs(logging_outputs)
 

fairseq/trainer.py

@@ -417,7 +417,7 @@ def maybe_no_sync():
             logging_output = self.task.aggregate_logging_outputs(
                 logging_outputs, self.get_criterion()
             )
-            sample_size = self.task.grad_denom(sample_sizes, self.get_criterion())
+            sample_size = sum(sample_sizes)
 
         if not all(k in logging_output for k in ["ntokens", "nsentences"]):
             raise Exception(
@@ -559,7 +559,7 @@ def valid_step(self, sample, raise_oom=False):
         logging_output = self.task.aggregate_logging_outputs(
             logging_output, self.get_criterion()
         )
-        sample_size = self.task.grad_denom(sample_size, self.get_criterion())
+        sample_size = sum(sample_size)
 
         # update meters for validation
         ntokens = logging_output.get("ntokens", 0)