fix prelu float16 bug (#35584)

python/paddle/fluid/layers/nn.py

@@ -9818,7 +9818,7 @@ def prelu(x, mode, param_attr=None, name=None):
             # [-0.2, 2., 3.]
 
     """
-    check_variable_and_dtype(x, 'x', ['float32', 'float64'], 'prelu')
+    check_variable_and_dtype(x, 'x', ['float16', 'float32', 'float64'], 'prelu')
 
     helper = LayerHelper('prelu', **locals())
     if mode not in ['all', 'channel', 'element']:
@@ -9843,7 +9843,7 @@ def prelu(x, mode, param_attr=None, name=None):
     alpha = helper.create_parameter(
         attr=helper.param_attr,
         shape=alpha_shape,
-        dtype='float32',
+        dtype=dtype,
         is_bias=False,
         default_initializer=Constant(0.25))
     out = helper.create_variable_for_type_inference(dtype)