#18539: faster matroid 3 connectivity
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Reporter: chaoxu | Owner: chaoxu
Type: enhancement | Status: new
Priority: major | Milestone: sage-6.8
Component: matroid theory | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/chaoxu/faster_matroid_3_connectivity|
84a81fdefe60c488faf9e4610c170c985e0c5f2f
Dependencies: | Stopgaps:
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Comment (by chaoxu):
Replying to [comment:18 Rudi]:
> The real inefficiency turned out to be in the set union operations, and
calculating with bitsets rather than python sets works miracles for that.
Great. Thanks I will review that code soon.
What is the abstract way to find components from a set of fundamental
cocircuits?
This code didn't return the same output as the original components.
{{{
B = self.basis()
components = []
for e in self.groundset() - B:
C = set(self._fundamental_cocircuit(B,e))
components2 = []
for comp in components:
if (C & comp):
C.update(comp)
else:
components2.append(comp)
components2.append(frozenset(C))
components = components2
components.extend([frozenset([e]) for e in self.loops()])
return components
}}}
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Ticket URL: <http://trac.sagemath.org/ticket/18539#comment:19>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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