Back off guide sections...

Until pymathics can handle this.

Author: rocky

pymathics/graph/__init__.py

@@ -50,8 +50,7 @@
     VertexList,
 )
 
-from pymathics.graph.measures_and_metrics.basic import EdgeCount, VertexCount
-from pymathics.graph.measures_and_metrics.degree import VertexDegree
+from pymathics.graph.measures_and_metrics import EdgeCount, VertexCount, VertexDegree
 
 from pymathics.graph.algorithms import *  # noqa
 from pymathics.graph.generators import *  # noqa

…hics/graph/measures_and_metrics/basic.py pymathics/graph/measures_and_metrics.pypymathics/graph/measures_and_metrics/basic.py renamed to pymathics/graph/measures_and_metrics.py pymathics/graph/measures_and_metrics/basic.py renamed to pymathics/graph/measures_and_metrics.py

@@ -1,21 +1,30 @@
 """
-Basic Graph Measures
+Graph Measures and Metrics
+
+Measures include basic measures, such as the number of vertices and edges, \
+connectivity, degree measures, centrality, and so on.
 """
 
+
 from typing import Optional
 
 from mathics.core.atoms import Integer
 from mathics.core.convert.expression import ListExpression
 from mathics.core.expression import Expression
 from mathics.core.symbols import Symbol
+from mathics.core.systemsymbols import SymbolLength
 
 from pymathics.graph.base import _NetworkXBuiltin
 
 # FIXME: add context
-SymbolLength = Symbol("Length")
 SymbolCases = Symbol("Cases")
 
 
+# FIXME put this in its own file/module basic
+# when pymathics doc can handle this.
+# """
+# Basic Graph Measures
+# """
 class _PatternCount(_NetworkXBuiltin):
     """
     Counts of vertices or edges, allowing rules to specify the graph.
@@ -62,6 +71,7 @@ class EdgeCount(_PatternCount):
      = 2
     """
 
+    no_doc = False
     summary_text = "count edges in graph"
 
     def _items(self, graph):
@@ -92,7 +102,52 @@ class VertexCount(_PatternCount):
      = 2
     """
 
+    no_doc = False
     summary_text = "count vertices in graph"
 
     def _items(self, graph):
         return graph.G.nodes
+
+
+# Put this in its own file/module "degree.py"
+# when pymathics doc can handle.
+# """
+# Graph Degree Measures
+# """
+
+
+class VertexDegree(_NetworkXBuiltin):
+    """
+    <url>
+    :WMA link:
+    https://reference.wolfram.com/language/ref/EdgeCount.html</url>
+
+    <dl>
+       <dt>'VertexDegree[$g$]'
+       <dd>returns a list of the degrees of each of the vertices in graph $g$.
+
+       <dt>'EdgeCount[$g$, $patt$]'
+       <dd>returns the number of edges that match the pattern $patt$.
+
+       <dt>'EdgeCount[{$v$->$w}, ...}, ...]'
+       <dd>uses rules $v$->$w$ to specify the graph $g$.
+    </dl>
+
+    >> VertexDegree[{1 <-> 2, 2 <-> 3, 2 <-> 4}]
+     = {1, 3, 1, 1}
+    """
+
+    no_doc = False
+    summary_text = "list graph vertex degrees"
+
+    def eval(self, graph, evaluation, options):
+        "%(name)s[graph_, OptionsPattern[%(name)s]]"
+
+        def degrees(graph):
+            degrees = dict(list(graph.G.degree(graph.vertices)))
+            return ListExpression(*[Integer(degrees.get(v, 0)) for v in graph.vertices])
+
+        return self._evaluate_atom(graph, options, degrees)
+
+
+# TODO: VertexInDegree, VertexOutDegree