We have now drastically reduced the dependency to .vertices() and .edges() in the graph module (except in doctests, but we can specify sort=True/False).
We must now identify the tasks to do and schedule the work.
Some issues to take care of in the graph module:
- #22349 Deprecate sorting of methods
.vertices() and .edges().
- methods using matrices:
adjacency_matrix, distance_matrix, etc. For all these methods, we can now give as input an ordering of the vertices that will be used to order rows and columns. Currently, we use .vertices() by default. If we switch to list(G) by default, we have to check that it's not breaking algorithms using these matrices.
- methods using
.relabel(). We must check that changing the default ordering of vertices/edges is safe. Should be ok, but we never know...
- methods for isomorphisms were we also have issues with labels (see e.g. #27232 although the case is certainly beyond what we should reasonably do).
- Deprecate sorting of vertex labels in method
iterator_edges of base/sparse_graph.pyx (so of the vertices of an edge). Deprecating this behavior is certainly a hard task. A first step could be to order the vertices according internal integer value, thus ensuring that (u, v) will always be ordered the same way.
And of course, changes done here will certainly break many methods in other modules...
