improve the doc

python/paddle/fluid/initializer.py

@@ -690,8 +690,9 @@ class MSRAInitializer(Initializer):
 
     Args:
         uniform (bool): whether to use uniform or normal distribution
-        fan_in (float32|None): fan_in for MSRAInitializer. If None, it is\
-        inferred from the variable. default is None.
+        fan_in (float32|None): fan_in (in_features) of trainable Tensor,\
+        If None, it will be infered automaticly. If you don't want to use in_features of the Tensor,\
+        you can set the value of 'fan_in' smartly by yourself. default is None.
         seed (int32): random seed
         negative_slope (float, optional): negative_slope (only used with leaky_relu). default is 0.0.
         nonlinearity(str, optional): the non-linear function. default is relu.

python/paddle/nn/initializer/kaiming.py

@@ -36,8 +36,9 @@ class KaimingNormal(MSRAInitializer):
         \frac{gain}{\sqrt{{fan\_in}}}
 
     Args:
-        fan_in (float32|None): fan_in for Kaiming normal Initializer. If None, it is\
-        inferred from the variable. default is None.
+        fan_in (float32|None): fan_in (in_features) of trainable Tensor,\
+        If None, it will be infered automaticly. If you don't want to use in_features of the Tensor,\
+        you can set the value of 'fan_in' smartly by yourself. default is None.
         negative_slope (float, optional): negative_slope (only used with leaky_relu). default is 0.0.
         nonlinearity(str, optional): the non-linear function. default is relu.
 
@@ -83,8 +84,9 @@ class KaimingUniform(MSRAInitializer):
         x = gain \times \sqrt{\frac{3}{fan\_in}}
 
     Args:
-        fan_in (float32|None): fan_in for Kaiming uniform Initializer. If None, it is\
-        inferred from the variable. default is None.
+        fan_in (float32|None): fan_in (in_features) of trainable Tensor,\
+        If None, it will be infered automaticly. If you don't want to use in_features of the Tensor,\
+        you can set the value of 'fan_in' smartly by yourself. default is None.
         negative_slope (float, optional): negative_slope (only used with leaky_relu). default is 0.0.
         nonlinearity(str, optional): the non-linear function. default is relu.