Fix error importing torch.optim.lr_scheduler.LRScheduler in PyTorch…

… 1.13

utils/__init__.py

@@ -211,14 +211,6 @@ def load_ckpt(
     print(f'| load {shown_model_name} from \'{checkpoint_path}\'.')
 
 
-
-
-
-
-
-    # return load_pre_train_model()
-
-
 def remove_padding(x, padding_idx=0):
     if x is None:
         return None
@@ -273,6 +265,13 @@ def build_object_from_class_name(cls_str, parent_cls, *args, **kwargs):
 
 
 def build_lr_scheduler_from_config(optimizer, scheduler_args):
+    try:
+        # PyTorch 2.0+
+        from torch.optim.lr_scheduler import LRScheduler as LRScheduler
+    except ImportError:
+        # PyTorch 1.X
+        from torch.optim.lr_scheduler import _LRScheduler as LRScheduler
+
     def helper(params):
         if isinstance(params, list):
             return [helper(s) for s in params]
@@ -287,18 +286,19 @@ def helper(params):
                 resolved['optimizer'] = optimizer
                 obj = build_object_from_class_name(
                     resolved['cls'],
-                    torch.optim.lr_scheduler.LRScheduler,
+                    LRScheduler,
                     **resolved
                 )
                 return obj
             return resolved
         else:
             return params
+
     resolved = helper(scheduler_args)
     resolved['optimizer'] = optimizer
     return build_object_from_class_name(
         scheduler_args['scheduler_cls'],
-        torch.optim.lr_scheduler.LRScheduler,
+        LRScheduler,
         **resolved
     )