#13289: Determine if a vertex is a cut vertex
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Reporter: dcoudert | Owner: jason, ncohen, rlm
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-5.3
Component: graph theory | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: David Coudert | Merged in:
Dependencies: | Stopgaps:
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Changes (by sluther):
* status: positive_review => needs_work
Comment:
There is major problem with this patch. It modifies the given graph.
While it tries to revert the effect, this is still a bad idea. If an
exception occurs between the removal of the vertex and the addition of the
edges then the graph will end up modified (just think of CTRL+C or out of
memory).
Also the reversal doesn't work for directed graphs currently. Just check
the number of edges of D in your test case.
I'd argue that you shouldn't try to fix the reversal, but get rid of it. I
don't now much about the problem, so can't suggest a better algorithm that
what a quick google search would reveal. If you can't find a better
algorithm, make a copy of the graph and modify this copy.
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13289#comment:10>
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