Does anyone know if it is assumed that if the _pos dictionary in a graph is not None, then it contains each vertex as a key? It seems like it is assumed several places in the code (e.g., in the subgraph() function). However, _pos isn't updated properly (e.g., in the delete_vertex function, the add_vertex function, etc.). This is leading to bugs in several other functions.
If there isn't a policy, then I think we ought to allow _pos to carry partial information about the graph, i.e., not all vertices have to have positions specified, if possible. Also, the _boundary list isn't being updated when vertices are deleted or a subgraph is made. I can patch this easily, though. Thanks, Jason --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
