[TTS] Scale sampler steps by number of devices

nemo/collections/tts/data/text_to_speech_dataset.py

@@ -139,12 +139,15 @@ def __init__(
             self.data_samples += samples
             self.sample_weights += weights
 
-    def get_sampler(self, batch_size: int) -> Optional[torch.utils.data.Sampler]:
+    def get_sampler(self, batch_size: int, world_size: int) -> Optional[torch.utils.data.Sampler]:
         if not self.weighted_sampling_steps_per_epoch:
             return None
 
         sampler = get_weighted_sampler(
-            sample_weights=self.sample_weights, batch_size=batch_size, num_steps=self.weighted_sampling_steps_per_epoch
+            sample_weights=self.sample_weights,
+            batch_size=batch_size,
+            world_size=world_size,
+            num_steps=self.weighted_sampling_steps_per_epoch,
         )
         return sampler
 

nemo/collections/tts/data/vocoder_dataset.py

@@ -166,12 +166,15 @@ def __init__(
             self.data_samples += samples
             self.sample_weights += weights
 
-    def get_sampler(self, batch_size: int) -> Optional[torch.utils.data.Sampler]:
+    def get_sampler(self, batch_size: int, world_size: int) -> Optional[torch.utils.data.Sampler]:
         if not self.weighted_sampling_steps_per_epoch:
             return None
 
         sampler = get_weighted_sampler(
-            sample_weights=self.sample_weights, batch_size=batch_size, num_steps=self.weighted_sampling_steps_per_epoch
+            sample_weights=self.sample_weights,
+            batch_size=batch_size,
+            world_size=world_size,
+            num_steps=self.weighted_sampling_steps_per_epoch,
         )
         return sampler
 
@@ -410,7 +413,7 @@ def _build_sample(self, tup):
 
         return example
 
-    def get_sampler(self, batch_size: int = 16):
+    def get_sampler(self, batch_size: int, world_size: int):
         """
         Currently sampler is not supported for tarred dataset.
         """

nemo/collections/tts/models/audio_codec.py

@@ -506,7 +506,7 @@ def get_dataset(self, cfg):
 
         dataset = instantiate(cfg.dataset)
 
-        sampler = dataset.get_sampler(cfg.dataloader_params.batch_size)
+        sampler = dataset.get_sampler(cfg.dataloader_params.batch_size, world_size=self.trainer.world_size)
         return dataset, sampler
 
     def _setup_train_dataloader(self, cfg):

nemo/collections/tts/models/fastpitch.py

@@ -600,7 +600,7 @@ def _setup_train_dataloader(self, cfg):
         with phon_mode:
             dataset = instantiate(cfg.dataset, text_tokenizer=self.vocab,)
 
-        sampler = dataset.get_sampler(cfg.dataloader_params.batch_size)
+        sampler = dataset.get_sampler(cfg.dataloader_params.batch_size, world_size=self.trainer.world_size)
         return torch.utils.data.DataLoader(
             dataset, collate_fn=dataset.collate_fn, sampler=sampler, **cfg.dataloader_params
         )

nemo/collections/tts/models/hifigan.py

@@ -337,7 +337,7 @@ def istft(mags, phase):
 
     def _setup_train_dataloader(self, cfg):
         dataset = instantiate(cfg.dataset)
-        sampler = dataset.get_sampler(cfg.dataloader_params.batch_size)
+        sampler = dataset.get_sampler(cfg.dataloader_params.batch_size, world_size=self.trainer.world_size)
         data_loader = torch.utils.data.DataLoader(
             dataset, collate_fn=dataset.collate_fn, sampler=sampler, **cfg.dataloader_params
         )

nemo/collections/tts/parts/utils/tts_dataset_utils.py

@@ -218,21 +218,22 @@ def filter_dataset_by_duration(entries: List[Dict[str, Any]], min_duration: floa
 
 
 def get_weighted_sampler(
-    sample_weights: List[float], batch_size: int, num_steps: int
+    sample_weights: List[float], batch_size: int, world_size: int, num_steps: int
 ) -> torch.utils.data.WeightedRandomSampler:
     """
     Create pytorch sampler for doing weighted random sampling.
 
     Args:
         sample_weights: List of sampling weights for all elements in the dataset.
         batch_size: Batch size to sample.
+        world_size: Number of devices being used.
         num_steps: Number of steps to be considered an epoch.
 
     Returns:
         Pytorch sampler
     """
     weights = torch.tensor(sample_weights, dtype=torch.float64)
-    num_samples = batch_size * num_steps
+    num_samples = batch_size * world_size * num_steps
     sampler = torch.utils.data.WeightedRandomSampler(weights=weights, num_samples=num_samples)
     return sampler