also add aliases in the backends

Author: mantepse

src/sage/graphs/base/c_graph.pyx

@@ -1418,7 +1418,7 @@ cdef class CGraphBackend(GenericGraphBackend):
         else:
             self._loops = False
 
-    def num_edges(self, directed):
+    def n_edges(self, directed):
         """
         Return the number of edges in ``self``.
 
@@ -1434,13 +1434,13 @@ cdef class CGraphBackend(GenericGraphBackend):
 
         .. SEEALSO::
 
-            - :meth:`num_verts`
+            - :meth:`n_vertices`
               -- return the order of this graph.
 
         EXAMPLES::
 
             sage: G = Graph(graphs.PetersenGraph())
-            sage: G._backend.num_edges(False)
+            sage: G._backend.n_edges(False)
             15
 
         TESTS:
@@ -1485,23 +1485,23 @@ cdef class CGraphBackend(GenericGraphBackend):
             2
             sage: from sage.graphs.base.sparse_graph import SparseGraphBackend
             sage: S = SparseGraphBackend(7)
-            sage: S.num_edges(False)
+            sage: S.n_edges(False)
             0
             sage: S.loops(True)
             sage: S.add_edge(1, 1, None, directed=False)
-            sage: S.num_edges(False)
+            sage: S.n_edges(False)
             1
             sage: S.multiple_edges(True)
             sage: S.add_edge(1, 1, None, directed=False)
-            sage: S.num_edges(False)
+            sage: S.n_edges(False)
             2
             sage: from sage.graphs.base.dense_graph import DenseGraphBackend
             sage: D = DenseGraphBackend(7)
-            sage: D.num_edges(False)
+            sage: D.n_edges(False)
             0
             sage: D.loops(True)
             sage: D.add_edge(1, 1, None, directed=False)
-            sage: D.num_edges(False)
+            sage: D.n_edges(False)
             1
         """
         if directed:
@@ -1521,25 +1521,29 @@ cdef class CGraphBackend(GenericGraphBackend):
             i = (i - k) // 2
             return i + k
 
-    def num_verts(self):
+    num_edges = n_edges
+
+    def n_vertices(self):
         """
         Return the number of vertices in ``self``.
 
         OUTPUT: the order of this graph
 
         .. SEEALSO::
 
-            - :meth:`num_edges`
+            - :meth:`n_edges`
               -- return the number of (directed) edges in this graph.
 
         EXAMPLES::
 
             sage: G = Graph(graphs.PetersenGraph())
-            sage: G._backend.num_verts()
+            sage: G._backend.n_vertices()
             10
         """
         return self.cg().num_verts
 
+    num_verts = n_vertices
+
     cdef bint _delete_edge_before_adding(self) noexcept:
         """
         Return whether we should delete edges before adding any.

src/sage/graphs/base/graph_backends.pyx

@@ -35,8 +35,8 @@ Any graph backend must redefine the following methods (for which
     :meth:`~GenericGraphBackend.loops` | Get/set whether or not ``self`` allows loops.
     :meth:`~GenericGraphBackend.multiple_edges` | Get/set whether or not ``self`` allows multiple edges.
     :meth:`~GenericGraphBackend.name` | Get/set name of ``self``.
-    :meth:`~GenericGraphBackend.num_edges` | The number of edges in ``self``
-    :meth:`~GenericGraphBackend.num_verts` | The number of vertices in ``self``
+    :meth:`~GenericGraphBackend.n_edges` | The number of edges in ``self``
+    :meth:`~GenericGraphBackend.n_vertices` | The number of vertices in ``self``
     :meth:`~GenericGraphBackend.relabel` | Relabel the vertices of ``self`` by a permutation.
     :meth:`~GenericGraphBackend.set_edge_label` | Label the edge `(u,v)` by `l`.
 
@@ -583,7 +583,7 @@ cdef class GenericGraphBackend(SageObject):
         """
         raise NotImplementedError()
 
-    def num_edges(self, directed):
+    def n_edges(self, directed):
         """
         Return the number of edges in ``self``.
 
@@ -594,31 +594,35 @@ cdef class GenericGraphBackend(SageObject):
         TESTS::
 
             sage: G = sage.graphs.base.graph_backends.GenericGraphBackend()
-            sage: G.num_edges(True)
+            sage: G.n_edges(True)
             Traceback (most recent call last):
             ...
             NotImplementedError
-            sage: G.num_edges(False)
+            sage: G.n_edges(False)
             Traceback (most recent call last):
             ...
             NotImplementedError
         """
         raise NotImplementedError()
 
-    def num_verts(self):
+    num_edges = n_edges
+
+    def n_vertices(self):
         """
         Return the number of vertices in ``self``.
 
         TESTS::
 
             sage: G = sage.graphs.base.graph_backends.GenericGraphBackend()
-            sage: G.num_verts()
+            sage: G.n_vertices()
             Traceback (most recent call last):
             ...
             NotImplementedError
         """
         raise NotImplementedError()
 
+    num_verts = n_vertices
+
     def relabel(self, perm, directed):
         """
         Relabel the vertices of ``self`` by a permutation.

src/sage/graphs/base/static_sparse_backend.pyx

@@ -980,19 +980,21 @@ cdef class StaticSparseBackend(CGraphBackend):
                 yield x
         return
 
-    def num_verts(self):
+    def n_vertices(self):
         r"""
         Return the number of vertices.
 
         TESTS::
 
             sage: from sage.graphs.base.static_sparse_backend import StaticSparseBackend
             sage: g = StaticSparseBackend(graphs.PetersenGraph())
-            sage: g.num_verts()
+            sage: g.n_vertices()
             10
         """
         return self._order
 
+    num_verts = n_vertices
+
     def allows_loops(self, value=None):
         r"""
         Return whether the graph allows loops.
@@ -1043,7 +1045,7 @@ cdef class StaticSparseBackend(CGraphBackend):
         else:
             raise ValueError("the graph is immutable and cannot be changed in any way")
 
-    def num_edges(self, directed):
+    def n_edges(self, directed):
         r"""
         Return the number of edges.
 
@@ -1056,13 +1058,13 @@ cdef class StaticSparseBackend(CGraphBackend):
 
             sage: from sage.graphs.base.static_sparse_backend import StaticSparseBackend
             sage: g = StaticSparseBackend(graphs.PetersenGraph())
-            sage: g.num_edges(False)
+            sage: g.n_edges(False)
             15
 
         Testing the exception::
 
             sage: g = StaticSparseBackend(digraphs.Circuit(4))
-            sage: g.num_edges(False)
+            sage: g.n_edges(False)
             Traceback (most recent call last):
             ...
             NotImplementedError: Sorry, I have no idea what is expected in this situation. I don't think that it is well-defined either, especially for multigraphs.
@@ -1095,6 +1097,8 @@ cdef class StaticSparseBackend(CGraphBackend):
                 # Returns the number of edges
                 return int(cg.g.m)
 
+    num_edges = n_edges
+
     def iterator_edges(self, vertices, bint labels):
         r"""
         Iterate over the graph's edges.

src/sage/graphs/digraph.py

@@ -1494,7 +1494,7 @@ def degree_polynomial(self):
 
         .. SEEALSO::
 
-            :meth:`num_verts` for the value at `(x, y) = (1, 1)`
+            :meth:`n_vertices` for the value at `(x, y) = (1, 1)`
 
         EXAMPLES::