#7640: shortest_path should not use NetworkX if the underlying graph is a
c_graph
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Reporter: rlm | Owner: rlm
Type: defect | Status: needs_review
Priority: major | Milestone: sage-4.3
Component: graph theory | Keywords:
Work_issues: | Author:
Upstream: N/A | Reviewer:
Merged: |
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Changes (by ncohen):
* status: needs_work => needs_review
Comment:
Well, in the end I corrected the first two errors, which were directly
errors in the algorithm ( I ignored the direction of arcs, which is now
fixed ).
The following ones are created by the enumeration of degree ( for example
the error in eulerian_orientation is not really one. The result given is
correct, but there is one inversion due to the fact that the order in the
listing of neighbors is not the same when you patch is applied :-)
This reminded me that your patch for c_graphs had not actually been tested
against the new Sage because of the slowness in the distance function.. As
eulerian_orientation does not care about distances ( I wrote this one :-)
), I do not think shortest_path is responsible for this one... Could you
take a look at the last bugs to see if it could come from the switching
process ( it it for sure in the case of eulerian_orientation ) ?
Actually, as it is not possible to test your switching patch without the
shortest)path functiom, perhaps we should merge the two in just one
patch....
We're almost there !!!!!!!!!! :-)
Nathann
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7640#comment:17>
Sage <http://www.sagemath.org>
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