#14666: Test if a weight function is generic for a given matroid
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Reporter: Stefan | Owner: Stefanf
Type: enhancement | Status: needs_review
Priority: minor | Milestone: sage-7.2
Component: matroid theory | Resolution:
Keywords: matroid, weight | Merged in:
function | Reviewers:
Authors: | Work issues:
Report Upstream: N/A | Commit:
Branch: | 059b6d3816eae7412bc5e6570c17888fa2b75678
public/ticket/14666 | Stopgaps:
Dependencies: |
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Comment (by darij):
I've made some changes (NB: branch change!), particularly documenting one
of the undocumented codepaths (namely, passing a dictionary for
``weight``). However, it exposed a bug: The algorithm assumes ``weight``
to be a function.
My suggestion here would be to change the way dictionaries are handled.
Rather than doing the try/excepts, I'd check whether ``weight`` is a
dictionary, and then define a function ``weight_fun`` to send each ``e``
to ``weight[e]``. Otherwise, I'd just set ``weight_fun = weight``. All
other uses of ``weight`` in the code should then be replaced by
``weight_fun``. Does this sound reasonable to you? (I haven't done any
speed comparisons or other tests, so this might not actually be a good
idea.)
Also, the algorithm looks nice and clean. I haven't proven it yet. Is it
easy or should I know something it follows from?
Thanks for the good work!
--
Ticket URL: <http://trac.sagemath.org/ticket/14666#comment:14>
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