Opened 3 years ago

Closed 3 years ago

Last modified 3 years ago

#26851 closed enhancement (fixed)

py3: avoid .vertices() and .edges() in union of graphs

Reported by: dcoudert Owned by:
Priority: major Milestone: sage-8.6
Component: graph theory Keywords: py3, graph
Cc: tscrim, chapoton Merged in:
Authors: David Coudert Reviewers: Frédéric Chapoton
Report Upstream: N/A Work issues:
Branch: 3e1ee4b (Commits, GitHub, GitLab) Commit: 3e1ee4b4232b37aecbac06b6c96340c72ada9c16
Dependencies: Stopgaps:

Status badges

Description (last modified by dcoudert)

This change is not without consequences. Indeed, when adding vertices to the graph G resulting from the union of self and other, the order in which vertices are added to G fixes the ordering list(G).

For instance, this change breaks the graph generator EllinghamHorton54Graph that uses several times disjoint_union which itself calls union and that uses the ordering of list(G) to relabel vertices. Also, we change the generator to something simpler and more robust.

Change History (4)

comment:1 Changed 3 years ago by dcoudert

  • Branch set to public/26851_union
  • Cc tscrim chapoton added
  • Commit set to 3e1ee4b4232b37aecbac06b6c96340c72ada9c16
  • Description modified (diff)
  • Status changed from new to needs_review

New commits:

942309btrac #26851: avoid .vertices and .edges in union
3e1ee4btrac #26851: fix EllinghamHorton54Graph

comment:2 Changed 3 years ago by chapoton

  • Reviewers set to Frédéric Chapoton
  • Status changed from needs_review to positive_review

ok, let it be

comment:3 Changed 3 years ago by vbraun

  • Branch changed from public/26851_union to 3e1ee4b4232b37aecbac06b6c96340c72ada9c16
  • Resolution set to fixed
  • Status changed from positive_review to closed

comment:4 Changed 3 years ago by embray

  • Milestone changed from sage-8.5 to sage-8.6

This tickets were closed as fixed after the Sage 8.5 release.

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