#18516: Posets: canonical_label() returns a poset from lattice
-------------------------------------+-------------------------------------
Reporter: jmantysalo | Owner:
Type: defect | Status: needs_info
Priority: major | Milestone: sage-6.8
Component: combinatorics | Resolution:
Keywords: | Merged in:
Authors: Jori Mäntysalo | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/jmantysalo/posets__canonical_label___returns_a_poset_from_lattice|
c742ca4204a252d2ebebe4a2dd6d037469f019c4
Dependencies: | Stopgaps:
-------------------------------------+-------------------------------------
Comment (by ncohen):
Hello !
> Why those `# random` parts on doctests?
Because the doctests wrongly assume that the canonical label should never
change. We had this problem with bliss: the canonical labels it returns
are different from the ones returned by 'native' Sage.
A labelling is 'canonical' in the sense that two isomorphic object will be
relabelled to the same object. This being said, nothing says that a
canonical label never changes in time, and in particular the documentation
of Nauty says explicitly that it will.
> And isn't `sorted` unneeded, as the order of 'a' and 'b' is always the
same?
I am not sure. These letters will be stored on dictionaries, and you never
know what happens with dictionaires on different architectures. Anyway I
removed that, because of your next comment:
> Also you say that this issue is now corrected, but give an example with
`relabel` function, not with `canonical_relabel`?
My mistake. I added another commit at the same location.
Nathann
--
Ticket URL: <http://trac.sagemath.org/ticket/18516#comment:15>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
