[Feat,BugFix] avoid shuffling train data by default; do not evaluate …

…rollout on very last epoch

rl4co/models/rl/common/base.py

@@ -36,7 +36,7 @@ class RL4COLitModule(LightningModule):
         lr_scheduler_interval: learning rate scheduler interval
         lr_scheduler_monitor: learning rate scheduler monitor
         generate_default_data: whether to generate default datasets, filling up the data directory
-        shuffle_train_dataloader: whether to shuffle training dataloader
+        shuffle_train_dataloader: whether to shuffle training dataloader. Default is False since we recreate dataset every epoch
         dataloader_num_workers: number of workers for dataloader
         data_dir: data directory
         metrics: metrics
@@ -50,7 +50,7 @@ def __init__(
         batch_size: int = 512,
         val_batch_size: int = None,
         test_batch_size: int = None,
-        train_data_size: int = 1_280_000,
+        train_data_size: int = 100_000,
         val_data_size: int = 10_000,
         test_data_size: int = 10_000,
         optimizer: Union[str, torch.optim.Optimizer, partial] = "Adam",
@@ -63,7 +63,7 @@ def __init__(
         lr_scheduler_interval: str = "epoch",
         lr_scheduler_monitor: str = "val/reward",
         generate_default_data: bool = False,
-        shuffle_train_dataloader: bool = True,
+        shuffle_train_dataloader: bool = False,
         dataloader_num_workers: int = 0,
         data_dir: str = "data/",
         log_on_step: bool = True,
@@ -278,8 +278,12 @@ def on_train_epoch_end(self):
         """Called at the end of the training epoch. This can be used for instance to update the train dataset
         with new data (which is the case in RL).
         """
-        train_dataset = self.env.dataset(self.data_cfg["train_data_size"], "train")
-        self.train_dataset = self.wrap_dataset(train_dataset)
+        # Only update if not in the first epoch
+        # If last epoch, we don't need to update since we will not use the dataset anymore
+        if self.current_epoch < self.trainer.max_epochs - 1:
+            log.info("Generating training dataset for next epoch...")
+            train_dataset = self.env.dataset(self.data_cfg["train_data_size"], "train")
+            self.train_dataset = self.wrap_dataset(train_dataset)
 
     def wrap_dataset(self, dataset):
         """Wrap dataset with policy-specific wrapper. This is useful i.e. in REINFORCE where we need to