Overwrote methods concerning subdivision of edge(s) in a matching covered graph

[janmenjayap]

The objective of this issue is to overwrite the methods pertaining to subdivision of edges in a matching covered graph.

More specifically, this PR aims to overwrite the following methods:

• subdivide_edge() | Subdivide an edge k times.
• subdivide_edges() | Subdivide k times edges from an iterable container.

This PR shall address the methods related to subdivision of edge(s) in matching covered graphs.

Fixes #38216.
Note that this issue fixes a small part of the mentioned issue.

This issue is the fresh restart of the issue #39650.

📝 Checklist

• The title is concise and informative.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation and checked the documentation preview.

⌛ Dependencies

Nothing as of now.

cc: @dcoudert.

[janmenjayap]

By the way,
While running ./sage -t src/sage/graphs/matching_covered_graph.py in my local, I have been getting this error

  File "/home/janmenjaya/open-source/sage/src/bin/sage-runtests", line 9, in <module>
    sys.exit(main())
             ^^^^^^
  File "/home/janmenjaya/open-source/sage/src/sage/doctest/__main__.py", line 192, in main
    err = DC.run()
          ^^^^^^^^
  File "/home/janmenjaya/open-source/sage/src/sage/doctest/control.py", line 1613, in run
    self.run_doctests()
  File "/home/janmenjaya/open-source/sage/src/sage/doctest/control.py", line 1197, in run_doctests
    self.dispatcher = DocTestDispatcher(self)
                      ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/janmenjaya/open-source/sage/src/sage/doctest/forker.py", line 1745, in __init__
    init_sage(controller)
  File "/home/janmenjaya/open-source/sage/src/sage/doctest/forker.py", line 218, in init_sage
    controller.load_environment()
  File "/home/janmenjaya/open-source/sage/src/sage/doctest/control.py", line 699, in load_environment
    return import_module(self.options.environment)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/janmenjaya/open-source/sage/local/var/lib/sage/venv-python3.12.5/lib/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 995, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/home/janmenjaya/open-source/sage/src/sage/repl/ipython_kernel/all_jupyter.py", line 6, in <module>
    from sage.all_cmdline import *
  File "/home/janmenjaya/open-source/sage/src/sage/all_cmdline.py", line 17, in <module>
    from sage.all import *
  File "/home/janmenjaya/open-source/sage/src/sage/all.py", line 97, in <module>
    from sage.graphs.all import *
  File "/home/janmenjaya/open-source/sage/src/sage/graphs/all.py", line 9, in <module>
    from sage.graphs.graph import Graph
  File "/home/janmenjaya/open-source/sage/src/sage/graphs/graph.py", line 436, in <module>
    class Graph(GenericGraph):
  File "/home/janmenjaya/open-source/sage/src/sage/graphs/graph.py", line 9551, in Graph
    from sage.graphs.connectivity import minimal_separators
ImportError: cannot import name 'minimal_separators' from 'sage.graphs.connectivity' (/home/janmenjaya/open-source/sage/src/sage/graphs/connectivity.cpython-312-x86_64-linux-gnu.so)

So, I essentially, just comment the line,

from sage.graphs.connectivity import minimal_separators

and the line

"minimal_separators"        : "Connectivity, orientations, trees",

in graph.py and run the doctests (which passes the tests). Any comments on this?

[dcoudert]

The problem should be elsewhere in your configuration. I don't have this issue on my local installation (macOS and fedora).

[janmenjayap]

Hi @dcoudert,
Please do let me know, if anything else is required to be done.