fix(mge/functional): fix scatter doctest failed for GPU platform issue

GitOrigin-RevId: b5f92c39dd46f13aee07e9cad441e017069aaa3a

python_module/megengine/functional/tensor.py

@@ -236,6 +236,14 @@ def scatter(inp: Tensor, axis: int, index: Tensor, source: Tensor) -> Tensor:
 
     Moreover, the values of :attr:`index` must be between ``0`` and ``inp.shape(axis) - 1`` inclusive.
 
+    .. note::
+        Please notice that, due to performance issues, the result is uncertain on the GPU device
+        if scatter difference positions from source to the same destination position
+        regard to index tensor.
+
+        Show the case using the following examples, the oup[0][2] is maybe
+        from source[0][2] which value is 0.2256 or source[1][2] which value is 0.5339
+        if set the index[1][2] from 1 to 0.
 
     :param inp: the inp tensor which to be scattered
     :param axis: the axis along which to index
@@ -252,17 +260,16 @@ def scatter(inp: Tensor, axis: int, index: Tensor, source: Tensor) -> Tensor:
 
         inp = tensor(np.zeros(shape=(3,5),dtype=np.float32))
         source = tensor([[0.9935,0.9465,0.2256,0.8926,0.4396],[0.7723,0.0718,0.5939,0.357,0.4576]])
-        index = tensor([[0,2,0,2,1],[2,0,0,1,2]])
+        index = tensor([[0,2,0,2,1],[2,0,1,1,2]])
         oup = F.scatter(inp, 0, index,source)
         print(oup.numpy())
 
     Outputs:
 
     .. testoutput::
-        :options: +SKIP
 
-        [[0.9935 0.0718 0.5939 0.     0.    ]
-         [0.     0.     0.     0.357  0.4396]
+        [[0.9935 0.0718 0.2256 0.     0.    ]
+         [0.     0.     0.5939 0.357  0.4396]
          [0.7723 0.9465 0.     0.8926 0.4576]]
 
     """