cherry-pick (#23925): tweak doc of dot and logsumexp, test=release/2.0 (#23999)

python/paddle/tensor/linalg.py

@@ -419,11 +419,13 @@ def dot(x, y, name=None):
        Only support 1-d Tensor(vector).
 
     Parameters:
-    
         x(Variable): 1-D ``Tensor`` or ``LoDTensor``. Its datatype should be ``float32``, ``float64``, ``int32``, ``int64``
         y(Variable): 1-D ``Tensor`` or ``LoDTensor``. Its datatype soulde be ``float32``, ``float64``, ``int32``, ``int64``
         name(str, optional): Name of the output. Default is None. It's used to print debug info for developers. Details: :ref:`api_guide_Name`
 
+    Returns:
+        Variable: the calculated result Tensor/LoDTensor.
+
     Examples:
 
     .. code-block:: python

python/paddle/tensor/math.py

@@ -1012,13 +1012,13 @@ def addmm(input, x, y, alpha=1.0, beta=1.0, name=None):
 
 def logsumexp(x, dim=None, keepdim=False, out=None, name=None):
     """
-This operator calculates the log of the sum of exponentials of the input Tensor.
+    This operator calculates the log of the sum of exponentials of the input Tensor.
 
-.. math::
+    .. math::
        logsumexp(x) = \log\sum exp(x)
 
 
-Parameters:
+    Parameters:
        x (Variable): Input LoDTensor or Tensor. Must be one of the following types: float32, float64.
        dim (list|int, optional): The dimensions along which the sum is performed. If :attr:`None`,
          sum all elements of :attr:`input` and return a Tensor variable with a single element,
@@ -1027,13 +1027,16 @@ Parameters:
        keep_dim (bool, optional): Whether to reserve the reduced dimension in the output Tensor.
          The result tensor will have one fewer dimension than the :attr:`input` unless :attr:`keep_dim`
          is true, default value is False.
+       out (Variable), optional):  Enable user to explicitly specify an output variable to save result.
        name (str, optional): The default value is None.  Normally there is no need for user to
          set this property.  For more information, please refer to :ref:`api_guide_Name`
 
+    Returns:
+       Variable: The calcuated result Tensor/LoDTensor.
 
-Examples:
+    Examples:
 
-.. code-block:: python
+    .. code-block:: python
 
         import paddle
         import paddle.fluid as fluid
@@ -1044,6 +1047,17 @@ Examples:
           x = fluid.dygraph.to_variable(np_x)
           print(paddle.logsumexp(x).numpy())
 
+    ..  code-block:: python
+
+        import paddle
+        import paddle.fluid as fluid
+        import numpy as np
+
+        with fluid.dygraph.guard():
+            np_x = np.random.uniform(0.1, 1, [2, 3, 4]).astype(np.float32)
+            x = fluid.dygraph.to_variable(np_x)
+            print(paddle.logsumexp(x, dim=1).numpy())
+            print(paddle.logsumexp(x, dim=[0, 2]).numpy())
 
     """
     op_type = 'logsumexp'