#17225: Degrees of looped *immutable* graphs are wrong
----------------------------+----------------------------
Reporter: kcrisman | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.4
Component: graph theory | Keywords:
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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See [http://stackoverflow.com/questions/26566823/sage-python-bug-in-
looped-graph-degree-computation this SO question].
{{{
q=graphs.CompleteGraph(2)
q.allow_loops(True)
q.allow_multiple_edges(True)
q.add_edge([1,1])
a=q.copy(immutable=True)
b=q.copy(immutable=False)
sage: a==b
True
sage: a.degree()
[1, 2]
sage: b.degree()
[1, 3]
}}}
Basically, the problem is that the usual backend has a case for this
{{{
if self._loops and self.has_edge(v, v, None):
if self._multiple_edges:
d += len(self.get_edge_label(v, v))
else:
d += 1
}}}
but the "static" one doesn't.
--
Ticket URL: <http://trac.sagemath.org/ticket/17225>
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