Deferring import of torch in config to allow faster import (Lightning-AI#2079)

Author: JackUrb

litgpt/config.py

@@ -5,7 +5,6 @@
 from pathlib import Path
 from typing import Any, List, Literal, Optional, Type, Union
 
-import torch
 import yaml
 from typing_extensions import Self
 
@@ -185,6 +184,8 @@ def norm_class(self) -> Type:
 
         from functools import partial
 
+        import torch  # Torch import is lazy to make config loading faster
+
         if self.norm_class_name == "RMSNorm":
             from litgpt.model import RMSNorm