Opened 6 years ago
Closed 6 years ago
#18045 closed defect (fixed)
Wrong result returned by is_planar on a given embedding
Reported by:  ncohen  Owned by:  

Priority:  major  Milestone:  sage6.6 
Component:  graph theory  Keywords:  
Cc:  Merged in:  
Authors:  Nathann Cohen  Reviewers:  Vincent Delecroix 
Report Upstream:  N/A  Work issues:  
Branch:  110c8fa (Commits, GitHub, GitLab)  Commit:  110c8fa7f74010a01187f1413e2e693868cf1a66 
Dependencies:  Stopgaps: 
Description (last modified by )
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 make the mistake again.
The problem was that the computations were run on the cached embedding (i.e _embedding
) instead of the one provided by the user.
Nathann
[1] http://ask.sagemath.org/question/26301/testingplanarityonembeddinggiveswrongresult/
Change History (11)
comment:1 Changed 6 years ago by
 Branch set to public/18045
 Description modified (diff)
 Status changed from new to needs_review
comment:2 Changed 6 years ago by
 Description modified (diff)
comment:3 Changed 6 years ago by
 Commit set to 38c4e50b38574c6b4be2bb9dbf3cd98b1d4f6eaf
comment:4 Changed 6 years ago by
 Commit changed from 38c4e50b38574c6b4be2bb9dbf3cd98b1d4f6eaf to 9ee0d6e19ed03501a03333dfa4815f947735c0bc
Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:
9ee0d6e  trac #18045: Wrong result returned by is_planar on a given embedding

comment:5 Changed 6 years ago by
 Reviewers set to Vincent Delecroix
One bug less in Sage! Cool!
Could you replace (see eg's)
by (see examples)
. It is very wrong as "e.g." is a latin abbreviation for "for example".
Vincent
comment:6 Changed 6 years ago by
 Status changed from needs_review to needs_work
comment:7 Changed 6 years ago by
 Commit changed from 9ee0d6e19ed03501a03333dfa4815f947735c0bc to 110c8fa7f74010a01187f1413e2e693868cf1a66
comment:8 Changed 6 years ago by
 Status changed from needs_work to needs_review
comment:9 Changed 6 years ago by
 Status changed from needs_review to positive_review
comment:10 Changed 6 years ago by
Thanks !
comment:11 Changed 6 years ago by
 Branch changed from public/18045 to 110c8fa7f74010a01187f1413e2e693868cf1a66
 Resolution set to fixed
 Status changed from positive_review to closed
Branch pushed to git repo; I updated commit sha1. New commits:
trac #18045: Wrong result returned by is_planar on a given embedding