Go over docs for graph measures and metrics...

Also add some examples which will also be used on the Danjo side in the gallery

Author: rocky

pymathics/graph/__init__.py

@@ -1,16 +1,40 @@
 """
 Graphs - Vertices and Edges
 
+
+A Graph is a tuple of a set of Nodes and Edges.
+
 Mathics3 Module that provides functions and variables for working with graphs.
 
-Example:
-   In[1]:= LoadModule["pymathics.graph"]
-   Out[1]= pymathics.graph
-   In[2]:= BinomialTree[3]
-   In[3]:= BinomialTree[6]
-   In[4]:= CompleteKaryTree[3, VertexLabels->True]
+Examples:
+
+   >> LoadModule["pymathics.graph"]
+    = pymathics.graph
+
+   >> BinomialTree[3, DirectedEdges->True]
+     = -Graph-
+
+   >> BalencedTree[3, 3]
+     = -Graph-
+
+   >> g = Graph[{1 -> 2, 2 -> 3, 3 <-> 4}, VertexLabels->True]
+    = -Graph-
+
+   >> ConnectedComponents[g]
+    = {{3, 4}, {2}, {1}}
+
+   >> WeaklyConnectedComponents[g]
+    = {{1, 2, 3, 4}}
+
+   >> GraphDistance[g, 1, 4]
+    = 3
+
+   >> GraphDistance[g, 3, 2]
+    = Infinity
 
-Networkx does the heavy lifting here.
+<url>
+:NetworkX:
+https://networkx.org</url> does the heavy lifting here.
 """
 
 from pymathics.graph.base import (

pymathics/graph/base.py

@@ -2,9 +2,6 @@
 
 """
 Core routines for working with Graphs.
-A Graph is a tuple of a set of Nodes and Edges.
-
-networkx does all the heavy lifting.
 """
 
 # uses networkx
@@ -1647,14 +1644,11 @@ def boxes_to_tex(self, elements, **options):
 class HITSCentrality(_Centrality):
     """
     <url>
-    :https://en.wikipedia.org/wiki/HITS_algorithm:
-    https://en.wikipedia.org/wiki/HITS_centrality</url> (<url>
-    :Networkx:
+    :NetworkX:
     https://networkx.org/documentation/networkx-2.8.8/reference/algorithms/\
-generated/networkx.algorithms.link_analysis.hits_alg.hits.html</url>,
-    <url>
+generated/networkx.algorithms.link_analysis.hits_alg.hits.html</url>, <url>
     :WMA:
-    https://reference.wolfram.com/language/ref/HITSCentrality.html</url>)
+    https://reference.wolfram.com/language/ref/HITSCentrality.html</url>
 
     <dl>
       <dt>'HITSCentrality'[$g$]

pymathics/graph/measures_and_metrics.py

@@ -55,7 +55,9 @@ def eval_patt(
 class EdgeCount(_PatternCount):
     """
     <url>
-    :WMA link:
+    :NetworkX:
+    https://networkx.org/documentation/latest/reference/generated/networkx.classes.function.edges.html#edges</url>, <url>
+    :WMA:
     https://reference.wolfram.com/language/ref/EdgeCount.html</url>
 
     <dl>
@@ -82,6 +84,12 @@ def _items(self, graph):
 
 class GraphDistance(_NetworkXBuiltin):
     """
+    <url>
+    :NetworkX:
+    https://networkx.org/documentation/latest/reference/algorithms/generated/networkx.algorithms.shortest_paths.generic.shortest_path_length.html</url>, <url>
+    :WMA:
+    https://reference.wolfram.com/language/ref/GraphDistance.html</url>
+
     <dl>
       <dt>'GraphDistance'[$g$, $s$, $t$]
       <dd>returns the distance from source vertex $s$ to target vertex $t$ in the graph $g$.
@@ -155,7 +163,9 @@ def eval_s_t(self, graph, s, t, expression, evaluation: Evaluation, options: dic
 class VertexCount(_PatternCount):
     """
     <url>
-    :WMA link:
+    :NetworkX:
+    https://networkx.org/documentation/latest/reference/generated/networkx.classes.function.nodes.html</url>, <url>
+    :WMA:
     https://reference.wolfram.com/language/ref/VertexCount.html</url>
 
     <dl>
@@ -193,8 +203,10 @@ def _items(self, graph):
 class VertexDegree(_NetworkXBuiltin):
     """
     <url>
-    :WMA link:
-    https://reference.wolfram.com/language/ref/EdgeCount.html</url>
+    :NetworkX:
+    https://networkx.org/documentation/latest/reference/classes/generated/networkx.Graph.degree.html</url>, <url>
+    :WMA:
+    https://reference.wolfram.com/language/ref/VertexDegree.html</url>
 
     <dl>
        <dt>'VertexDegree[$g$]'