#1314: graphs: calculate tutte polynomial
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Reporter: jason | Owner: rlm
Type: enhancement | Status: new
Priority: major | Milestone: sage-wishlist
Component: graph theory | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Comment (by mhansen):
Replying to [comment:24 azi]:
> Btw, there is a minor bug in tutte.sage. In the corner case
>
> {{{
> 257 if G.num_edges() == 0:
> 258 return 1
> }}}
Yep. One of the things that helps a lot is being able to avoid copying
the graph. For the Tutte polynomial code, we just make one copy of the
graph on the initial call, but never copy it afterward. I found context
managers useful to manage mutating the graph and restoring it.
Also, I think the edge selection strategy has a bit of an effect on the
speed of the chromatic polynomial computation as well.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/1314#comment:25>
Sage <http://www.sagemath.org>
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