#18045: Wrong result returned by is_planar on a given embedding
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Reporter: ncohen | Owner:
Type: defect | Status: needs_review
Priority: major | Milestone: sage-6.6
Component: graph theory | Resolution:
Keywords: | Merged in:
Authors: Nathann Cohen | Reviewers:
Report Upstream: N/A | Work issues:
Branch: public/18045 | Commit:
Dependencies: | Stopgaps:
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Changes (by ncohen):
* status: new => needs_review
* branch: => public/18045
Old description:
> As reported on AskSage [1], the function `.is_planar` can return wrong
> results when given a specific embedding to run its computations on.
>
> This actually comes from a mistake in a `if/else` and variable types, as
> `bool(a_dictionary)` returns `True` when the dictionary is nonempty. The
> original authors did not seem to be aware of that, and once fixed the
> code does not mak the mistake again.
>
> Nathann
>
> [1] http://ask.sagemath.org/question/26301/testing-planarity-on-
> embedding-gives-wrong-result/
New description:
As reported on `AskSage` [1], the function `.is_planar` can return wrong
results when given a specific embedding to run its computations on.
This actually comes from a mistake in a `if/else` and variable types, as
`bool(a_dictionary)` returns `True` when the dictionary is nonempty. The
original authors did not seem to be aware of that, and once fixed the code
does not mak the mistake again.
Nathann
[1] http://ask.sagemath.org/question/26301/testing-planarity-on-embedding-
gives-wrong-result/
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Ticket URL: <http://trac.sagemath.org/ticket/18045#comment:1>
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