Opened 6 years ago

Last modified 16 months ago

#15060 new defect

The empty graph once again — at Version 1

Reported by: darij Owned by:
Priority: major Milestone: sage-8.4
Component: combinatorics Keywords: graphs, border cases, bitset, memleak
Cc: sage-combinat, pelegm Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description (last modified by darij)

sage: Graph({}).is_connected()
True

If my understanding of good terminology is correct, this should not be the case (see http://ncatlab.org/nlab/show/too+simple+to+be+simple ). Note that Graph({}).is_tree() correctly returns False.

Another issue is that

Graph({}).is_triangle_free()

seems to allocate lots of RAM and possibly die with a MemoryError? (it did so on the Sage cell server; on my machine I had to ctrl-alt-del the VM). The culprit seems to be Bitset(capacity=0). It looks like is_triangle_free is the only method ever using the Bitset(capacity=X) construction, so I'm not opening up a new ticket for this.

Change History (1)

comment:1 Changed 6 years ago by darij

  • Cc sage-combinat added; sagecombinat removed
  • Description modified (diff)
  • Keywords bitset added
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