Update topo_api.rst

docs/topo_api.rst

@@ -1,5 +1,30 @@
 Topology Related Utility Functions
 ==================================
 
+We provide several popular static and dynamic topologies.
+
+* Static Topology
+    * ExponentialGraph, ExponentialTwoGraph
+    * SymmetricExponentialGraph
+    * MeshGrid2DGraph
+    * StarGraph, RingGraph
+    * FullyConnectedGraph
+
+* Dynamic Topology
+    * GetDynamicSendRecvRanks
+    * GetExp2DynamicSendRecvMachineRanks
+    * GetInnerOuterRingDynamicSendRecvRanks
+    * GetInnerOuterExpo2DynamicSendRecvRanks
+
+* Utility Function
+    * IsRegularGraph
+    * IsTopologyEquivalent
+    * GetSendWeights, GetRecvWeights
+
+You can also write your own topology strategy as long as your static topology function returns
+a `networkx.DiGraph <https://networkx.org/documentation/stable/reference/classes/digraph.html>`_ 
+object and dynamic topology function (generator more accurately) yields
+a list of send neighbor and receive neighbor ranks in each call.
+
 .. automodule:: bluefog.common.topology_util
-    :members:
+    :exclude-members: List, Tuple, Dict, Iterator, isPowerOf