#15836: BasisMatroid.circuits() returns a malformed SetSystem when called on the
empty matroid
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Reporter: Rudi | Owner: Rudi
Type: defect | Status: positive_review
Priority: minor | Milestone: sage-6.2
Component: matroid theory | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/Rudi/ticket/15836 | 329566023aaef2d2f534bfe7cf1753052055b335
Dependencies: | Stopgaps:
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Changes (by Jayant):
* status: needs_review => positive_review
Comment:
The error no longer occurs because of ground set size checks added.
On an unrelated note, I noticed that if one gives bad input e.g. asking
for size 9 independent sets of (ground set size 8) vamos matroid:
{{{
from sage.matroids.advanced import *
M = BasisMatroid(matroids.named_matroids.Vamos())
len(M.independent_r_sets(9))
}}}
creates a segfault. There is a check in code for negative numbers passed
but not for positive numbers strictly greater than ground set size. I
suppose making the code stupid-proof would be a different ticket by
itself.
--
Ticket URL: <http://trac.sagemath.org/ticket/15836#comment:4>
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