[Precision] Change lm_head layer running in float32 (#3596)

* support lm_head fp32 bf16 fp16

* delete print

* code check

* check

* check

* code check

* check

* check

fastdeploy/model_executor/layers/utils.py

@@ -15,6 +15,7 @@
 """
 
 import functools
+from contextlib import contextmanager
 from typing import Tuple, Union
 
 import numpy as np
@@ -377,3 +378,15 @@ def create_empty_tensor(shape: Tuple[int, ...], dtype: Union[paddle.dtype, str])
         paddle.Tensor: An empty tensor with the specified shape and data type.
     """
     return paddle.empty(list(shape), dtype=dtype)
+
+
+@contextmanager
+def temporary_dtype(dtype: str):
+    """Temporarily set Paddle default dtype"""
+    orig_dtype = paddle.get_default_dtype()
+    try:
+        if dtype is not None and dtype == "float32":
+            paddle.set_default_dtype(dtype)
+        yield
+    finally:
+        paddle.set_default_dtype(orig_dtype)