!15571 Update MindSpore Doc Topk,Unique,UniqueWithPad

From: @dinglinhe123
Reviewed-by: @liangchenghui,@wuxuejian
Signed-off-by: @liangchenghui

mindspore/ops/operations/array_ops.py

@@ -748,11 +748,10 @@ class Unique(Primitive):
     Returns the unique elements of input tensor and also return a tensor containing the index of each value of input
     tensor corresponding to the output unique tensor.
 
-    This operation returns a tuple that contains the tensor `y` and the tensor `idx`;
-    where the tensor `y` contains unique elements along the `axis` of the tensor.
-    The sorting order of the unique elements is the same as the order that
-    they appear along the `axis` in `x`. Another tensor `idx` has the same size as the number of elements in `x`
-    along the `axis` dimension. It contains the index in the unique output `y`.
+    The shape of Tensor `y` and Tensor `idx` is different in most cases, because Tensor `y` will be deduplicated,
+    and the shape of Tensor `idx` is consistent with the input.
+
+    To get the same shape between `idx` and `y`, please ref to 'UniqueWithPad' operator
 
     Inputs:
         - **x** (Tensor) - The input tensor.
@@ -970,11 +969,11 @@ class UniqueWithPad(PrimitiveWithInfer):
     """
     Returns unique elements and relative indexes in 1-D tensor, filled with padding num.
 
-    The basic function is the same as the Unique operator, but the operator adds a Pad function.
-    The returned tuple(`y`,`idx`) after the input tensor x is processed by the unique operator,
+    The basic function is the same as the Unique operator, but the UniqueWithPad operator adds a Pad function.
+    The returned tuple(`y`,`idx`) after the input Tensor `x` is processed by the unique operator,
     in which the shapes of `y` and `idx` are mostly not equal. Therefore, in order to solve the above situation,
-    the UniqueWithPad operator will fill the `y` tensor with the number specified by the user
-    to make it have the same shape as the tensor `idx`.
+    the UniqueWithPad operator will fill the `y` Tensor with the `pad_num` specified by the user
+    to make it have the same shape as the Tensor `idx`.
 
     Inputs:
         - **x** (Tensor) - The tensor need to be unique. Must be 1-D vector with types: int32, int64.

mindspore/ops/operations/math_ops.py

@@ -1423,7 +1423,7 @@ class SquaredDifference(_MathBinaryOp):
 
      .. math::
 
-        out_{i} = (x_{i} + y_{i}) * (x_{i} - y_{i}) = x_{i}^2 - y_{i}^2
+        out_{i} = (x_{i} - y_{i}) * (x_{i} - y_{i}) = (x_{i} - y_{i})^2
 
     Inputs:
         - **input_x** (Union[Tensor, Number, bool]) - The first input is a number, or a bool,

mindspore/ops/operations/nn_ops.py

@@ -2079,12 +2079,15 @@ class TopK(PrimitiveWithInfer):
     """
     Finds values and indices of the `k` largest entries along the last dimension.
 
-    If the input is a one-dimensional Tensor, find the k largest entries in the Tensor,
-    and output its value and index as a Tensor. Therefore, "values [k]" is the "k" largest item in "input",
-    and its index is "indices [k]".
+    If the `input_x` is a one-dimensional Tensor, finds the `k` largest entries in the Tensor,
+    and outputs its value and index as a Tensor. Therefore, values[`k`] is the `k` largest item in `input_x`,
+    and its index is indices [`k`].
 
     For a multi-dimensional matrix,
-    calculate the first k entries in each row (corresponding vector along the last dimension), therefore:
+    calculates the first `k` entries in each row (corresponding vector along the last dimension), therefore:
+
+    .. math::
+
     values.shape = indices.shape = input.shape[:-1] + [k].
 
     If the two compared elements are the same, the one with the smaller index value is returned first.