Implementation of cycle_basis_edges

docs/source/api/algorithm_functions/connectivity_and_cycles.rst

@@ -17,6 +17,7 @@ Connectivity and Cycles
    rustworkx.weakly_connected_components
    rustworkx.is_weakly_connected
    rustworkx.cycle_basis
+   rustworkx.cycle_basis_edges
    rustworkx.simple_cycles
    rustworkx.digraph_find_cycle
    rustworkx.articulation_points

releasenotes/notes/add-cycle-basis-edges-5cb31eac7e41096d.yaml

@@ -0,0 +1,61 @@
+---
+features:
+  - |
+    A function, ``cycle_basis_edges`` was added to the crate
+    ``rustworkx-core`` in the ``connectivity`` module. This function returns 
+    the edge indices that form the cycle basis of a graph.
+  - |
+    Added a new function :func:`~rustworkx.cycle_basis_edges`  which is similar
+    to the existing :func:`~.cycle_basis` function but instead of returning node
+    indices it returns a list of edge indices for the cycle.
+
+    .. jupyter-execute::
+
+      import rustworkx
+      from rustworkx.visualization import * # Needs matplotlib/
+
+      graph = rustworkx.PyGraph()
+
+      # Each time add node is called, it returns a new node index
+      a = graph.add_node("A")
+      b = graph.add_node("B")
+      c = graph.add_node("C")
+      d = graph.add_node("D")
+      e = graph.add_node("E")
+      f = graph.add_node("F")
+      g = graph.add_node("G")
+      h = graph.add_node("H")
+      i = graph.add_node("I")
+      j = graph.add_node("J")
+
+      # add_edges_from takes tuples of node indices and weights,
+      # and returns edge indices
+      graph.add_edges_from([
+          (a, b, 1.5), 
+          (a, a, 1.0), 
+          (a, c, 5.0), 
+          (b, c, 2.5), 
+          (c, d, 1.3), 
+          (d, e, 0.8), 
+          (e, f, 1.6), 
+          (f, d, 0.7), 
+          (e, g, 0.7), 
+          (g, h, 0.9), 
+          (g, i, 1.0), 
+          (i, j, 0.8),
+      ])
+
+      mpl_draw(graph, with_labels=True)
+      # Retrieve EdgeIDs by enabling the edges flag.
+      cycles_edges = rustworkx.cycle_basis_edges(graph, a)
+      edge_list = list(graph.edge_list())
+      cycle_info = [[edge_list[edge] for edge in cycle] for cycle in cycles_edges]
+      # Print the EdgeID's that form cycles in the graph
+      display(cycles_edges)
+      # Print the data retrieved from the graph.
+      display(cycle_info)
+upgrade:
+  - |
+    The trait bounds of :func:`rustworkx_core::connectivity::cycle_basis` now 
+    requires graphs to be compatible with the trait ``IntoEdges`` and that the 
+    attribute ``EdgeId`` conforms to `Eq` and `Hash`.