#14967: Bug with DiGraph
-----------------------------+-------------------------------
Reporter: mercatp | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-5.11
Component: graph theory | Keywords: graph
Merged in: | Authors: Paul Mercat
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Dependencies: | Stopgaps:
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I've found the following bug with DiGraph :
{{{#!python
sage: G=DiGraph({0:{},1/2:{}});G
DiGraph on 1 vertex
}}}
I've found where is the error. It's in the file
$SAGE_ROOT/sage/graphs/base/c_graph.pyx, in function get_vertex :
{{{#!python
try:
u_int = u
except StandardError:
return -1
}}}
should be replaced by :
{{{#!python
from sage.rings.integer_ring import IntegerRing
if u in IntegerRing():
u_int = int(u)
else:
return -1
}}}
I've tried, and it corrects the problem.
But I'm not sure that it's the right way to correct the problem, because I
don't understand exactly how this code works. For me it's very weird (and
a source of bugs) to distinguish whether or not u is an integer : it
should be any hashable vertex and that's all. Why they wants to have the
integer corresponding to u (as an index in the hash table) be equal to u
when u is an integer ?
--
Ticket URL: <http://trac.sagemath.org/ticket/14967>
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