#14667: Matroid union
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Reporter: Stefan | Owner: Stefanf
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-6.2
Component: matroid theory | Resolution:
Keywords: matroid | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/Rajesh_Veeranki/ticket/14667 | 3f0e407ab7f9e145e029fa0a13423ab47c01e4d6
Dependencies: | Stopgaps:
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Changes (by Stefan):
* status: needs_review => needs_work
* commit: => 3f0e407ab7f9e145e029fa0a13423ab47c01e4d6
Comment:
1) I would not import this into the main namespace; rather I'd create a
"submenu" matroids.constructions, just like we have
matroids.named_matroids now.
2) Instead of computing the full list of bases, which is an expensive
operation, I'd return a RankMatroid with the appropriate rank function
(implemented efficiently using matroid intersection). Matroid Union is
likely to be applied to fairly large matroids, derived from graphs,
whereas BasisMatroid is optimized for small matroids.
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New commits:
||[http://git.sagemath.org/sage.git/commit/?id=3f0e407ab7f9e145e029fa0a13423ab47c01e4d6
3f0e407]||{{{Added MatroidUnion function in constructions.py}}}||
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Ticket URL: <http://trac.sagemath.org/ticket/14667#comment:8>
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