[skip ci] Update docs/snode.rst 2

docs/snode.rst

@@ -25,6 +25,32 @@ See :ref:`layout` for more details about data layout.
     :parameter x: (tensor) tensor(s) to be placed
     :return: (SNode) the ``snode`` itself
 
+.. function:: snode.get_shape(index)
+
+    :parameter snode: (SNode)
+    :parameter index: alone which axis? (0 for ``i`` and 1 for ``j``)
+    :return: (scalar) the size of tensor alone that axis
+
+    Equivalent to snode.shape[i]
+
+    ::
+        
+        ti.root.dense(ti.ijk, (3, 5, 4)).place(x)
+        x.get_shape(0)  # 3
+        x.get_shape(1)  # 5
+        x.get_shape(2)  # 4
+
+.. function:: snode.dim()
+
+    :parameter snode: (SNode or tensor)
+    :return: (scalar) the dimension of node / tensor
+
+    Equivalent to `len(snode.shape)`.
+
+    ::
+        
+        ti.root.dense(ti.ijk, (8, 9, 10)).place(x)
+        x.dim()  # 3
 
 .. function:: ti.root