#18910: Boost minimum spanning tree
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Reporter: borassi | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-6.8
Component: graph theory | Resolution:
Keywords: Boost, minimum | Merged in:
spanning tree | Reviewers:
Authors: Michele Borassi | Work issues:
Report Upstream: N/A | Commit:
Branch: | 8278b0bf8b3b4c86bdc5b543f5ca57c8b682f83a
u/borassi/boost_minimum_spanning_tree| Stopgaps:
Dependencies: #18876, #18906 |
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Comment (by dcoudert):
The weight function you use does not allow to access all possible stuff
that might be stored on an edge. For instance, I may have an edge like
`(u, v, {'weight':3, 'toto':4})` in which case a function like
`weight_function=lambda e:e[2]['weight']` is possible. With current
implementation, you assume that `weight_function((u,v))` returns the
weight. Better to have `weight_function(e)` or `weight_function((u,v,l))`.
Also, could you be a bit more specific with the description of the weight
function
{{{
- ``weight_function`` -- A function that takes an edge and returns a
numeric weight. If ``None`` (default), the algorithm uses the
edge
weights, if available, otherwise it assigns weight 1 to each
edge (in
the latter case, the output can be any spanning tree).
}}}
In particular, the default behavior assume that edge weights are numbers,
that is if `e=(u,v,l)` then `l` is a number.
David.
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Ticket URL: <http://trac.sagemath.org/ticket/18910#comment:5>
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